A taxonomic survey of oedogonium (oedogoniales, chlorophyta) in the South Island and Chatham Islands, New Zealand

Transcription

1 New Zealand Journal of Botany ISSN: X (Print) (Online) Journal homepage: A taxonomic survey of oedogonium (oedogoniales, chlorophyta) in the South Island and Chatham Islands, New Zealand Philip M. Novis To cite this article: Philip M. Novis (2003) A taxonomic survey of oedogonium (oedogoniales, chlorophyta) in the South Island and Chatham Islands, New Zealand, New Zealand Journal of Botany, 41:2, , DOI: / X To link to this article: Published online: 17 Mar Submit your article to this journal Article views: 1000 Citing articles: 4 View citing articles Full Terms & Conditions of access and use can be found at

2 New Zealand Journal of Botany, 2003, Vol. 41: X/03/ $7.00 The Royal Society of New Zealand A taxonomic survey of Oedogonium (Oedogoniales, Chlorophyta) in the South Island and Chatham Islands, New Zealand PHILIP M. NOVIS Landcare Research P.O. Box 69 Lincoln 8152, New Zealand NovisP@LandcareResearch.co.nz Abstract A survey of freshwater habitats, mainly streams and rivers, from Nelson, Canterbury, Westland, Southland, and the Chatham Islands revealed 20 taxa of Oedogonium that could be identified below genus level. Oedogonium was found in 46% of all samples examined. Fertile material appeared in 29% of samples containing the genus; however, it was much more common (54%) in samples from Canterbury than from other regions (12-20%). Two new species and three new varieties are proposed: O. braunii var. grande, O. cyathigerum var. laevis, O. subdissimile var. submasculum, O. southlandiae, and O. didymum. In identification, structure of male filaments was often found to be as important as the more commonly described female structures. Only five previously recorded species of Oedogonium in New Zealand have included any description of male material. Several species (including O. cyathigerum var. laevis and O. subdissimile var. submasculum) displayed subtle differences from Northern Hemisphere descriptions when structures of male material were compared. B02061; published 11 June 2003 Received 2 September 2002; accepted 19 March 2003 Keywords Oedogonium; filamentous green algae; taxonomy; distribution; New Zealand INTRODUCTION The filamentous green alga Oedogonium Link is extremely common and widespread in New Zealand streams and rivers (Biggs & Kilroy 2000). Although its characteristic cell caps make the genus easy to recognise, fertile specimens are required for specieslevel identifications to be made. Field material usually consists of masses of vegetative filaments, so identification to species level is rare. Biggs & Price (1987) found Oedogonium in 57 out of 153 rivers containing filamentous algal proliferations, but none could be identified below genus. Specimens were found across a wide range of conditions, suggesting that a large number of species could be involved. The sexual cycle may be complex: three types of motile cells and at least three types of filaments are involved in the life cycle of an idioandrosporous, nanandrous species (Graham & Wilcox 2000). Over 450 species have been described worldwide (Mrozinska 1985). Of the 26 species recorded previously from New Zealand, only 15 included any description or illustration. Male structures were observed in five taxa: the antheridia were described in four of these, and illustrated in one instance. These four records, O. crispum, O. pringsheimii (Nordstedt 1888), O. chapmanii (Tiffany 1948), and O. sexangulare (Hill 1970), are the only reliable species records of New Zealand Oedogonium prior to the present study. Here, 15 species, 10 varieties, and 3 forms (including autonyms) are described, of which 12,7, and 2, respectively, are new records for New Zealand. These include two species and three varieties proposed as new to science.

3 336 New Zealand Journal of Botany, 2003, Vol. 41 South Island North Island Fig. 1 Sampling localities and occurrence of Oedogonium. O, Oedogonium that formed fertile structures in crude culture; Ø, Oedogonium that did not form fertile structures; ı, no Oedogonium. Chatham Islands sample and three sites from Southland not shown (withheld by request of landowners). 43 S 200 Kilometres METHODS One hundred and twenty samples were received from collectors working for regional councils and other research institutes (Fig. 1; see Acknowledgments), and I made a further 79 collections in Canterbury and Southland. Simple environmental parameters were recorded during collection of material. Conductivity and ph were measured using a Hanna HI9812 combination meter, and water clarity using a NIWA clarity tube (Biggs et al. 1998). Some specimens sent by regional council workers were accompanied by measurements of ph, conductivity, and turbidity. The latter was converted to clarity tube readings (for consistency with Canterbury and Southland measurements) using Biggs & Kilroy (2002, equation 1). Between collection and processing, the samples were incubated in a growth chamber (M.S.I. Honeywell) at 16 C, 16:8 hours light:dark photoperiod, and irradiance of approximately 150 µmol m 2 s 1. Initial examination was carried out as soon as possible after collection. Samples containing the genus Oedogonium were incubated for further intervals, sometimes as long as 3 months, to generate fertile material from the vegetative filaments. Phototactic rings that formed at menisci within the tubes were scraped off with a small piece of cotton wool held by forceps, and the fertile filaments separated on a slide under the dissector microscope. Filaments remaining in the incubated water were also examined. Permanent mounts were made for each slide containing fertile material, using 40% Karo solution. These and subsamples of the original

4 Novis Oedogonium in South and Chathams Islands 337 Table 1 Classification of the taxa described in this study according to the system of Mrozinska (1991). Section Group Taxon Monospermatozoideae Dispermatozoideae C E F N O P Q s 12. O. pyrulum 19. O. platygynum var. novae-zelandiae 11. O. cymatosporum var. areoliferum 10. O. southlandiae 1.O. pringsheimii var. goczalkowicensis 2. O. pringsheimii var. nordstedtii 3. O. pringsheimii var. nordstedtii f. pachydermatosporum 4. O. pseudomitratum 5. O. subdissimile 6. O. subdissimile var. submasculum 13. O. crispum var. crispum f. obesum 14. O. crispum var. gracilescens 7. O. capillare 9. O. gracilius 15. O. didymum 20. O. cf. wissmanii 17. O. cyathigerum var. laevis 16. O. braunii var. grande 18. O. macrandrium var. hohenackerii Table 2 Frequency of occurrence of Oedogonium in each province, and percentages that could be made fertile. Province Samples examined Oedogonium present Fertile material obtained Canterbury Westland Nelson Southland Total (46%) 17 (59%) 20 (38%) 21 (49%) 84 (46%) 14 (54%) 2 (12%) 4 (20%) 4 (19%) 24 (29%) material (preserved in a solution of 70% ethanol and glycerine) were deposited in the Allan Herbarium (CHR). Descriptions, illustrations, and photomicrographs were taken using a Leica DMLB microscope with bright field and Nomarski Differential Interference Contrast (DIC) optics, drawing tube attachment, and a Wild MPS 51 S camera system. Identifications were made according to Mrozinska (1985), Gauthier-Lièvre (1963, 1964), and Skinner (1980). For convenience, the taxa are arranged in broad groups according to morphology, rather than the phylogenetic groups of Mrozinska (1991); however, placements into the latter groups are presented in Table 1. RESULTS Distribution of Oedogonium The genus was found in similar percentages of samples from different regions throughout the South Island (38-59%; Table 2; Fig. 1). However, a far greater proportion of taxa collected from Canterbury could be induced to fertility (54%, versus 12-20% in samples from other areas; Table 2; Fig. 1). The distributions of these fertile taxa are presented in Fig. 2 and included with their descriptions below. Locations are given using the New Zealand Metric Grid (NZMG). The "Tokano River" sampled by Nordstedt (1888) is assumed to be the Tokaanu Stream near Turangi.

5 338 New Zealand Journal of Botany, 2003, Vol S,4 Otago 172 E Nelson 5 /^ ) ) Marlbo/ough t 2«3,11,15 2,6 11 B * 2 \<\, 13,16,20 12 $9,10 Canterbury Fig. 2 Distributions of fertile strains of Oedogonium. 1, O. pringsheimii cf. var. goczalkowicensis; 2, O. pringsheimii cf. var. nordstedtii; 3, O. pringsheimii var. nordstedtii f. pachydermatosporum; 4, O. cf. pseudomitratum; 5, O. subdissimile; 6, O. subdissimile var. submasculum; 7, O. capillare; 8, O. cf. capillare; 9, O. gracilius; 10, O. sp. aff. pyrulum; 11, O. crispum var. crispum f. obesum; 12, O. crispum var. gracilescens; 13,O. didymum; 14, O. braunii var. grande; 15, O. cyathigerum var. laevis; 16, O. macrandrium var. hohenackerii; 17, O. cf. wissmanii; 18, indeterminate fertile Oedogonium. Not shown: O. southlandiae (location withheld at request of landowner); O. cymatosporum var. areoliferum and O. platygynum var. novaezelandiae (Chatham Islands). Distributions of some species are of lesser reliability (see descriptions)., Southland Kilometres Key to the New Zealand species of Oedogonium 1 Walls undulate 20. O. cf. wismannii Walls smooth 2 2 Macrandrous 3 Nanandrous 17 J Dioecious 4 Monoecious 13 4 Vegetative filaments < 20 µm wide 5 Vegetative filaments > 20 µm wide 10 5 Male and female filaments of equal width 6 Male filaments thinner than in females 7 6 Oospore µm long 5. O. subdissimile Oospore µmlong 4. O. cf. pseudomitratum 7 Oospores do not usually fill the oogonia 8 Oospores always fill the oogonia 6. O. subdissimile var. submasculum 8 Terminal hair present 1. O. pringsheimii cf. var. goczalkowicensis Terminal hair absent 9 9 Oogonia inverted pyriform 2. O. pringsheimii cf. var. nordstedtii Oogonia other shape 3. O. pringsheimii var. nordstedtii f. pachydermatosporum 10 Male and female filaments of equal width 11 Male filaments thinner than in females 12

6 Novis Oedogonium in South and Chathams Islands Oogonium not conspicuously swollen; no terminal hair 8. O. cf. capillare Oogonium conspicuously swollen; short terminal hair 9. O. gracilius 12 Two sperm cells per antheridial cell; 3-5 antheridial cells in series 7. O. capillare One sperm cell per antheridial cell; up to 18 antheridial cells in series 10. O. southlandiae 13 Two sperm cells per antheridial cell 14 One sperm cell per antheridial cell Sperm cells derived by longitudinal division in parent cell 15. O. didymum Sperm cells derived by transverse division in parent cell Vegetative cells < 20 µm wide 14. O. crispum var. gracilescens Vegetative cells mostly > 20 µm wide 13. O. crispum var. crispum f. obesum 16 Oospore sculptured 11. O. cymatosporum var. areoliferum Oospore not sculptured 12. O. sp. aff.pyrulum 17 Filaments thick (support cells up to 60 µm wide) 17. O. cyathigerum var. laevis Filaments thinner Oogonium with star-shaped transverse section 19. O. platygynum var. novae-zelandiae Oogonium with circular transverse section Oogonium with median opening 16. O. braunii var. grande Oogonium with superior opening 18. O. macrandrium var. hohenackerii TAXONOMY Group 1: dioecious, macrandrous, vegetative cells < 20 µm wide 1. Oedogonium pringsheimii C.E.Cramer cf. var. goczalkowicensis Mrozinska Fig. 3AJ-AO, 4G-H REFERENCES: Mrozinska 1985, p. 199, fig FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, µm wide, µm long, length:width , smooth-walled, each containing 1 pyrenoid. Basal cell swollen, µm wide, µm long, with rhizoidal holdfast. Male filaments narrower (10 µm wide). Antheridia 9 µm wide, 5-8 µm long, terminal, 4 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia single, spherical to ellipsoidal, µm wide, µm long, opening with superior suture. Support cells appear similar to other vegetative cells. Oospore spherical to oblong, µm wide, µm long, smooth-walled. SPECIMENS: CHR B pro parte (microscope slide). REMARKS: Size of specimens agrees more closely with var. pringsheimii C.E.Cramer, but the variable shape of the oospores (especially the more ellipsoidal shapes) are like those of var. goczalkowicensis. DISTRIBUTION: Canterbury: Pudding Hill Stream (NZMG E, N). A new record for New Zealand. The type was described from Poland (Mrozinska 1985). WATER QUALITY: Conductivity 90 µs cm 1, ph 7.4, clarity 100%. 2. Oedogonium pringsheimii C.E.Cramer cf. var. nordstedtii Wittr. Fig. 3F-K, 4E-F SYNONYM: O. pringsheimii var. varians Nordst. REFERENCES: Nordstedt 1888, p. 11; Mrozinska 1985, p. 197, fig FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, µm wide, µm long, length:width , smooth-walled, containing 1-2 pyrenoids. Basal cell swollen, with rhizoidal holdfast. Male filaments narrower (10-11 µm wide). Antheridia 8-9 µm wide, 6-7 µm long, terminal, 3 in series. Spermatozoids not seen. Oogonia inverted pyriform, single, µm wide, µm long, opening with ring-like suture in superior position. Support cells appear similar to other vegetative cells. Oospore spherical, µm diameter, smoothwalled. SPECIMENS: CHR B pro parte (microscope slide). REMARKS: The specimens agree with the published description (Mrozinska 1985) except for the oospore (smaller than reported). However, oospore size agrees well with Nordstedt's (1888) description of O. pringsheimii var. varians, included in var. nordstedtii by Mrozinska (1985). Size of the female filaments agrees very well with O. abbreviatum (Hirn) L.H.Tiffany (Mrozinska 1985, p. 202, fig. 295), the male filaments of which are not reduced in size. DISTRIBUTION: Canterbury: Ribbonwood Stream (NZMG E, N); possibly (no males observed) Forest Creek (NZMG E,

7 340 New Zealand Journal of Botany, 2003, Vol N), Phantom River (NZMG E, N), and Selwyn River (NZMG E, N). Material from the latter three sites was tentatively identified based on the distinctive pyriform oogonia. Southland: possibly (no males observed) stream near Te Anau (NZMG E, N). Cosmopolitan. Reported from the Tokaanu Stream near Turangi (as O. pringsheimii var. varians by Nordstedt 1888, who did not observe male filaments). WATER QUALITY: Conductivity µs cm 1, ph , clarity %. 3. Oedogonium pringsheimii C.E.Cramer var. nordstedtii f. pachydermatosporum (Nordst.) Hirn Fig. 3AD-AI, 4C-D REFERENCES: Mrozinska 1985, p. 199, fig FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, µm wide, µm long, length:width , smooth-walled, each containing 1 pyrenoid. Basal cell swollen, 15 µm wide, 30 µm long, with rhizoidal holdfast. Male filaments narrower (9 µm wide). Antheridia 7-8 µm wide, 5 µm long, terminal or intercalary, 3-4 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia spherical, to slightly compressed longitudinally, to ellipsoidal, 1-3 in series, µm wide, µm long, opening with outer suture and inner pore in superior position. Support cells appear similar to other vegetative cells. Oospore spherical to ellipsoidal, µm wide, µm long, smooth-walled, almost filling oogonium. SPECIMENS: CHR B pro parte (microscope slide). REMARKS: Specimens agree well with the published description (Mrozinska 1985), except that short terminal hairs have not yet been observed in New Zealand material. The oogonia of this form are never inverted pyriform in shape, a clear distinction from f. norstedtii. DISTRIBUTION: Canterbury: unnamed stream at Kennedys Road (NZMG E, N). A new record for New Zealand. Found previously in standing water in Hawaii and Poland (Mrozinska 1985). WATER QUALITY: Conductivity 480 µs cm 1, ph 6.8, clarity 52%. 4. Oedogonium cf. pseudomitratum Prescott Fig. 3L-T, 4K REFERENCES: Scott & Prescott 1958, pp , fig. 27:1-2; Mrozinska 1985, p. 195, fig FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, µm wide, µm long, length:width , smooth-walled, each containing 1 pyrenoid. Basal cell swollen (18 µm wide, 30 µm long), with rhizoidal holdfast. Male filaments as wide as females. Antheridia 9-10 µm wide, 5-6 µm long, intercalary, 1-5 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia single, pyriform, µm wide, µm long, opening with outer suture and inner pore in superior position. Support cells appear similar to other vegetative cells. Oospore spherical, rarely pyriform, µm wide, µm long, smooth-walled. SPECIMENS: CHR C pro parte (microscope slide). REMARKS: Specimens differ from the O. pringsheimii group because the male filaments are not reduced in size. The published description of O. pseudomitratum (Scott & Prescott 1958; Mrozinska 1985) is based on little material possibly only one fertile female filament, with no males observed. This makes the identification tenuous because the size of the male filaments is an important discriminating Fig. 3 Oedogonium spp. A-E, O. subdissimile var. submasculum: A-C, female filaments containing oogonia; D, male filament containing antheridia with 2 spermatozoids; E, basal cell. F-K, O. pringsheimii cf. var. nordstedtii: F-I, female filaments containing oogonia; J, male filament with terminal antheridium; K, basal cell. L-T, O. cf. pseudomitratum: L, basal cell; M-R, female filaments containing oogonia; S, T, male filaments containing antheridia. U-AC, O. subdissimile: U-Z, female filaments containing oogonia; AA, basal cell; AB, AC, male filaments containing antheridia. AD-AI, O. pringsheimii var. nordstedtii f. pachydermatosporum: AD-AF, female filaments containing oogonia (note that AD and AF are different pieces of the same filament); AG, basal cell; AH, AI, male filaments containing antheridia with spermatozoids. AJ-AO, O. pringsheimii cf. var. goczalkowicensis: AJ-AL, female filaments containing oogonia; AM, basal cell; AN, variation in terminal structure; AO, male filament containing antheridia with spermatozoids. AP-AU, O. capillare: AP-AR, female filaments containing oogonia; AS, male filament containing antheridia; AT, antheridia with spermatozoids; AU, vegetative filament showing strongly capped cell ends. Scale bars = 10 µm. Use scale 2 for C, D, I, R, Y, Z, AB, AC, AI, AL, AT. Use scale 1 for remainder.

8 Novis Oedogonium in South and Chathams Islands 341

9 342 New Zealand Journal of Botany, 2003, Vol. 41 factor. There is no information on variation of the type (and no confirmation that the type is macrandrous). The illustrations of Scott & Prescott (1958) show capitellate vegetative cells, which contrasts with the New Zealand specimens. However, the dimensions of the female New Zealand material are close enough to support this identification, pending further information about the type material. DISTRIBUTION: South Canterbury: Waihao River North Branch (NZMG E, N). A new record for New Zealand. The type was described from Arnhem Land (Northern Territory, Australia; Scott & Prescott 1958). WATER QUALITY: Conductivity 50 µs cm- 1, ph 7.7, clarity 100%. 5. Oedogonium subdissimile C.C.Jao Fig. 3U-AC, 4I-J REFERENCES: Jao 1979, p. 325, fig. 27; Mrozinska 1985, p. 98, fig. 94. FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, µm wide, µm long, length:width , smooth-walled, containing 1 pyrenoid. Basal cell swollen, µm wide, µm long, with rhizoidal holdfast. Male filaments as wide as female. Antheridia 8-10 µm wide, 5-7 µm long, terminal, rarely intercalary, 2-5 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia single or in pairs, inverted pyriform, 25-32(-35) µm wide, µm long, opening with outer suture and inner pore in superior position. Support cells appear similar to other vegetative cells. Oospore spherical to slightly pyriform, 21-25(-28) µm wide, µm long, smooth-walled. SPECIMENS: CHR B pro parte (microscope slide). REMARKS: The specimens differ slightly from those described previously (Jao 1979; Mrozinska 1985) in two ways: the antheridial cells are about half as long (although the cross walls of these may be difficult to see), and the oospores do not always completely fill the oogonia. The illustrations of Jao (1979) suggest that intercalary antheridia were more common in the type material. DISTRIBUTION: Canterbury: Hinds River at SH1 (NZMG E, N); Southland: stream near Manapouri (NZMG E, N); Westland: Stillwater Creek (NZMG E, N); Nelson: Lee River (NZMG E, N). New record for New Zealand; previously reported from standing water in Hubei Province, China (Jao 1979, cited in Mrozinska 1985). WATER QUALITY: Conductivity µs cm 1, ph , clarity %. 6. Oedogonium subdissimile C.C.Jao var. submasculum Novis, var. nov. Fig. 3A-E, 4A-B Dioecium, macrandrum. Cellulae vegetativae cylindricae, 11 16( 18) µm latae, µm longae, ratione arithmetica longitudinis:latitudinis , tenuitunicatae, pyrenoidem unicam per cellulam continentes. Cellula basalis tumida, 20 µm lata, 33 µm longa, retinaculo rhizoidali praedita. Antheridia 9 µm lata, 7-8 µm longa, terminalia, 2 in serie disposita, 2 spermatozoidia ex partitione transversali in cellula parentis exorta per antheridium continentia. Filamentum masculum quoad statura deminutum. Oogonia unica, inverse pyriformia, µm lata, µm longa, ex sutura externa atque poro interno in positione superiore aperientia. Cellulae suffultoriae ut videtur cellulis aliis vegetativis similes. Oospora sphaerica vel subpyriformis, (21 )25 31 µm lata, µm longa, tenuitunicata, oogonium fere implens. Fig. 4 Photomicrographs of Oedogonium spp. A, B, O. subdissimile var. submasculum: A, female filament with opening to oogonium (arrowhead) (note that oospore fills oogonium); B, male filament with antheridial cells (arrowhead) containing spermatozoids. C, D, O.pringsheimii var. nordstedtii f. pachydermatosporum: C, female filament containing two oogonia, with the opening of one visible (arrowhead); D, male filament showing antheridial cells (arrowhead) containing spermatozoids. E, F, O.pringsheimii cf. var. nordstedtii: E, oogonium with suture (arrowhead); F, antheridia lacking spermatozoids (note highly developed "collar" (arrowhead)). G, H, O.pringsheimii cf. var. goczalkowicensis: G, oogonium with opening (arrowhead); H, antheridia (arrowhead) containing spermatozoids. I, J, O. subdissimile. I, oogonium with part of suture visible (arrowhead); J, antheridia (arrowhead) containing spermatozoids (note collar structure (arrow)). K, O. cf. pseudomitratum. Oogonium with opening (arrowhead). L, M, O. capillare: L, female filament containing oogonium; M, male filament containing intercalary antheridia (arrowheads). N-Q, O. southlandiae: N, female filament containing oogonium (note unusually thickened wall (arrowhead; this feature is not always present)); O, short chain of antheridia, containing spermatozoids (arrowheads); P, long chain (arrowhead indicates antheridia, arrow shows vegetative cell); Q, high magnification view of antheridia showing single spermatozoids. Scale bars = 10 µm. Use scale 1 for C, L-P. Use scale 2 for remainder.

10 Novis Oedogonium in South and Chathams Islands 343

11 344 New Zealand Journal of Botany, 2003, Vol. 41 HOLOTYPE: New Zealand, Westland, Burkes Creek, D. Cottam (WCRC), 1 February 2002, CHR B pro parte (microscope slide). FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, 11 16( 18) µm wide, µm long, length: width , smooth-walled, each containing 1 pyrenoid. Basal cell swollen, 20 µm wide, 33 µm long, with rhizoidal holdfast. Male filaments narrower (10 µm wide). Antheridia 9 µm wide, 7-8 µm long, terminal, 2 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia single, inverted pyriform, µm wide, µm long, opening with outer suture and inner pore in superior position. Support cells appear similar to other vegetative cells. Oospore spherical to slightly pyriform, (21 )25 31 µm wide, µm long, smooth-walled, almost filling oogonium. REMARKS: Reduced size of the male filaments justifies the new variety. Antheridia are also less abundant and consist of fewer cells. The variety name refers to the smaller size of the male filaments compared with the female (in the type variety, the male filaments are 9-14 µm wide). DISTRIBUTION: Westland: Burkes Creek at SH69 (NZMG E, N); possibly (no males observed) South Canterbury: Phantom River (NZMG E, N). WATER QUALITY: Conductivity 50 µs cm 1, ph 7.6, clarity 100%. Group 2: dioecious, macrandrous, vegetative cells > 20 µm wide 7. Oedogonium capillare (L.) Kütz. Fig. 3AP-AT, 4L,M REFERENCES: Kützing 1843, p , fig. 12(II): 1-3; Hirn (1900), p , fig. 11:58; Mrozinska 1985, p. 111, fig. 117A,B. FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, µm wide, µm long, length:width , smooth-walled, containing 5-12 pyrenoids. Basal cell not observed. Male filaments narrower (vegetative cells 30 µm wide). Antheridia µm wide, 4-6 µm long, intercalary, 3-5 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia single, only slightly swollen, µm wide, µm long, opening with outer suture and inner pore slightly supramedian. Support cells appear similar to other vegetative cells. Oospore spherical to longitudinally compressed to oblong, µm wide, µm long, smooth-walled. SPECIMENS: CHR B pro parte (microscope slide). REMARKS: Oogonia in these specimens protrude a little more than in the illustrations of Hirn (1900) and Mrozinska (1985), but they are still within the reported size range, and closely resemble the illustrations of Kützing (1843). The male filaments, however, are up to 5 µm narrower than reported. DISTRIBUTION: South Canterbury: Temuka River at SH1 (NZMG E, ); possibly (no males observed) Southland: stream near Te Anau (NZMG E, N). Cosmopolitan, though the previous record from New Zealand (Brand 1911) is very doubtful as there is no description or illustration and no specific locality. WATER QUALITY: Conductivity 70 µs cm 1, ph 7.3, clarity 30% (no data from Temuka River). 8. Oedogonium cf. capillare (L.) Kütz. Fig. 5Q-V, 6A-C REFERENCES: Kützing 1843, p , fig. 12(II): 1-3; Hirn (1900), p , fig. 11:58; Mrozinska 1985, p. 111, fig. 117A,B. FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, µm wide, µm long, length:width , smooth-walled. Pyrenoids not distinguished. Basal cell not observed. Male filaments as wide as females. Antheridia µm wide, 9-12 µm long, intercalary, 3-5 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia single, not swollen, cylindrical, µm wide, µm long, Fig. 5 Oedogonium spp. A-F, O. southlandiae: A-C, female filaments containing oogonia; D, base of filament; E, chain of antheridia; F, antheridia containing single spermatozoids. G-K, O. cymatosporum var. areoliferum: G-I, fertile material containing oogonia and antheridia; J, K, oogonia containing oospores with sculptured wall. L-P, O. gracilius: L-N, female filaments containing oogonia; O, male filament with antheridia containing spermatozoids; P, variation in basal cell. Q-V, O. cf. capillare: Q, R, female filaments with oospores; S-U, male filaments with antheridia and spermatozoids; V, vegetative filament showing strongly capped cells. W-Z, O. sp. aff. pyrulum. W, X, fertile filaments; Y, basal cell; Z, antheridia. AA-AE, O. crispum var. gracilescens: AA-AD, fertile filaments; AE, basal cell. AF-AL, O. crispum var. crispum f. obesum: AF, basal cell; AG-AL, fertile filaments. Scale bars = 10 µm. Use scale 1 for U. Use scale 3 for F, I, J, K, Z. Use scale 2 for remainder.

12 Novis Oedogonium in South and Chathams Islands 345 A O

13 346 New Zealand Journal of Botany, 2003, Vol. 41 opening with superior pore. Support cells appear similar to other vegetative cells. Oospore spherical to oblong, µm wide, µm long, smoothwalled. SPECIMENS: CHR B pro parte (microscope slide). REMARKS: The O. capillare complex consists of large forms in which the oogonia are not swollen to a width much greater than the vegetative cells. Differences between taxa are subtle. In this case, although the males were abundant (very unusual for Oedogonium), oospores were rarely seen. It is possible that the "oospores" observed were actually deformed or infected vegetative cells, because there was no swelling of the oogonia whatsoever. More female material is required to confirm the identification. DISTRIBUTION: Southland: Hillpoint Stream at WaikanaRoad (NZMG E, N). Also see comments for O. capillare. WATER QUALITY: Conductivity 83 µs cm 1, clarity 80%. 9. Oedogonium gracilius (Wittr.) Tiffany Fig. 5L-P, 6D-F REFERENCES: Wittrock 1878, p ; Mrozinska 1985, p. 103, fig FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, (18-)20-29 µm wide, µm long, length:width , smooth-walled, containing 1-5 pyrenoids. Basal cell slightly swollen, µm wide, µm long, with rhizoidal holdfast. Short terminal hair, about 10 µm long, on tip of growing filaments. Male filaments as wide as female. Antheridia µm wide, 3-5 µm long, intercalary, 2-5 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia single, spherical to oblong, µm wide, µm long, opening with superior pore. Support cells appear similar to other vegetative cells. Oospore spherical to slightly ellipsoidal, (28-)35-41 µm wide, µm long, smooth-walled. SPECIMENS: CHR C pro parte (microscope slide). REMARKS: The specimens agree well with the published description. There is very little to distinguish between O. gracilius and O. plagiostomum Wittr. (Mrozinska 1985, p. 102, fig. 102) and it is possible that these taxa are identical: Wittrock (1878) commented that these taxa are distinguished by only a few dimensions. However, the terminal hair described here has not been recorded for either species. DISTRIBUTION: South Canterbury: Temuka River at SH1 (NZMG E, ); possibly (no males observed) in a stream near Mossburn, Southland (exact location withheld at request of landowner). Cosmopolitan, but a new record for New Zealand. WATER QUALITY: Conductivity 70 µs cm 1, ph 8.1, clarity 76% (no data available for Temuka River). 10. Oedogonium southlandiae Novis, sp. nov. Fig. 4N-Q, 5A-F Dioecium, macrandrum. Cellulae vegetativae cylindricae, µm latae, µm longae, ratione arithmetica longitudinis:latitudinis , tenuitunicatae, non capitellatae, 5-9 pyrenoides continentes. Cellula basalis tumida, µm lata, µm longa, retinaculo simplici praedita. Antheridia µm lata, 4-6 µm longa, intercalaria, 18 in serie disposita, spermatozoidium unicum per antheridium continentia. Filamentum masculum quoad statura deminutum, usque µm latum. Oogonia spherica vel oblonga, unica, 44-50(-55) µm lata, 43-57(-60) µm longa. Porus superior, ellipticus, interdum constrictus. Cellulae suffultoriae ut videtur cellulis aliis vegetativis similes. Oospora sphaerica vel oblonga, 38 43(-52) µm lata, µm longa, tenuitunicata. HOLOTYPE: New Zealand, Southland, unnamed stream near Mossburn, P. Novis, 11 March 2002, CHR B pro parte (microscope slide, female), CHR C pro parte (microscope slide, male). FEATURES: Dioecious, macrandrous. Vegetative cells cylindrical, µm wide, µm long, length:width , smooth-walled, containing 5-9 pyrenoids. Basal cell swollen, µm wide, µm long, with simple holdfast. Male filaments narrower (23-30 µm wide). Antheridia µm wide, 4-6 µm long, intercalary, 18 in series, each containing 1 spermatozoid. Oogonia spherical to oblong, single, 44-50(-55) µm wide, 43-57(-60) µm long. Pore superior, elliptical, sometimes constricted. Support cells appear similar to other vegetative cells. Oospore spherical to oblong, 38-43(-52) µm wide, µm long, smooth-walled. REMARKS: The new species is justified by antheridia containing single spermatozoids. In size of cell and shape of oogonium, the specimens are close to O. capilliforme var. capilliforme f. lorentzii (Magnus & Wille) Hirn, and in O. grande Kützing owing to long chains of antheridia. However, both these taxa

14 Novis Oedogonium in South and Chathams Islands 347 contain two spermatozoids in their antheridia. The specific epithet refers to Southland, the district where the specimens were found. DISTRIBUTION: Southland stream near Mossburn (exact location withheld at request of landowner). WATER QUALITY: Conductivity 70 µs cm 1, ph 8.1, clarity 76%. Group 3: monoecious, single spermatozoid 11. Oedogonium cymatosporum Wittr. & Nordst. var. areoliferum C.C Jao Fig. 5G-K, 6G-J REFERENCES: Jao 1934, p , fig. 286: 4-5; Mrozinska 1985, p. 261, fig FEATURES: Monoecious. Vegetative cells cylindrical, 7-8 µm wide, µm long, length:width , smooth-walled. Pyrenoids not observed. Basal cell not seen. Antheridia 7-8 µm wide, 7-10 µm long, intercalary, 1-2 in series, each containing 1 spermatozoid. Oogonia ellipsoidal, compressed longitudinally, single, µm wide, µm long, opening with a median ring-like fissure. Support cells appear similar to other vegetative cells. Oospore ellipsoidal, compressed longitudinally, µm wide, µm long, outer wall smooth, median wall sculpted with polygonal areolae approximately 3-5 µm wide. SPECIMENS: CHR C pro parte (microscope slide), from a preserved sample, T. Worthy, 1978, held at CHR. REMARKS: Specimens agree very well with published descriptions (Jao 1934; Mrozinska 1985), especially regarding sculpture on the oospore wall. DISTRIBUTION: Pond draining peatland, Chatham Island. Previously described from Europe and North America, but a new record for New Zealand. WATER QUALITY: unknown. 12. Oedogonium sp. aff. pyrulum Wittr. Fig. 5W-Z, 6K REFERENCES: Wittrock 1872, p. 2; Mrozinska 1985, p. 152, fig FEATURES: Monoecious. Vegetative cells cylindrical, µm wide, µm long, length:width , smooth-walled, containing 1 pyrenoid. Basal cell slightly swollen, µm wide, µm long, with very attenuated simple holdfast. Only short filaments (up to 7 cells) observed. Antheridia µm wide, 5-8 µm long, intercalary, 1-2 in series, each containing 1 spermatozoid. Oogonia single, inverted pyriform, µm wide, µm long, opening with suture at top. Support cells appear similar to other vegetative cells. Oospores not seen. SPECIMENS: CHR B pro parte (microscope slide). REMARKS: Only a small amount of material was found, and did not include any mature oospores. The identification assumes that the oospores are spherical and smooth-walled, which would leave O. pyrulum as the sole alternative; if so, then a new variety would be justified because the specimens are larger than the published dimensions (Wittrock 1872; Mrozinska 1985) in all instances except the length of the antheridial cells. DISTRIBUTION: South Canterbury: Temuka River at SH1 (NZMG E, N). Found previously at Addisons Flat (Skuja 1976), but lack of information makes the record doubtful. Mainly reported from Asia and Scandinavia. WATER QUALITY: Unknown. Group 4: monoecious, 2 spermatozoids derived by transverse division in antheridium 13. Oedogonium crispum (Hassall) Wittr. var. crispum f. obesum (Wittr.) Mrozinska Fig. 5AF-AL, 6L REFERENCES: Mrozinska 1985, p. 156, fig FEATURES: Monoecious. Vegetative cells cylindrical, 19-21(-27) µm wide, µm long, length:width , smooth-walled, containing 1 pyrenoid. Basal cell slightly swollen, 20 µm wide, 45 µm long, with rhizoidal holdfast. Antheridia µm wide, 5-8 µm long, intercalary, 1-5 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia single, spherical to inverted pyriform, (35-)45-60 µm wide, (39-)44-55 µm long, opening with suture at top. Support cells appear similar to other vegetative cells. Oospores spherical, smooth-walled, µm diameter, not completely filling the oogonia. SPECIMENS: CHR B pro parte (microscope slide). REMARKS: The O. crispum complex consists of many forms, generally separated from each other by subtle differences. Identification of f. obesum is based on the oogonia, which are completely filled by the oospores in all other forms and varieties of O. crispum. However, the filament size is a little too large. This may be the most common taxon in the South Island, or at least the easiest to induce to fertility. O. crispum has been found at Ohaeawai (Northland) and the Tokaanu Stream, near Turangi

15 348 New Zealand Journal of Botany, 2003, Vol. 41 (Nordstedt 1888), but description of the oogonium is not detailed enough to identify that record beyond species. DISTRIBUTION: Canterbury: Opihi River at Fairlie- Tekapo Road (NZMG E, N); unnamed stream at Kennedys Road (NZMG E, N); Newton Stream at Esk confluence (NZMG E, N); possibly (very little material) Hinds River at SH1 (NZMG E, N). Southland: Hillpoint Stream at Waikana Road (NZMG E, N). Cosmopolitan, but a new record for New Zealand. WATER QUALITY: Conductivity µs cm 1, ph , clarity %. 14. Oedogonium crispum (Hassall) Wittr. var. gracilescens Wittr. Fig. 5AA-AE, 6M REFERENCES: Mrozinska 1985, p. 158, fig FEATURES: Monoecious. Vegetative cells cylindrical, 9-19 µm wide, µm long, length:width , smooth-walled, containing 1 4pyrenoids. Basal cell slightly swollen, 10 µm wide, 40 µm long, with rhizoidal holdfast. Antheridia 10-11( 15) µm wide, 5-8 µm long, intercalary or terminal, 1-3 in series, each containing 2 spermatozoids arising from transverse division in parent cell. Oogonia single or in pairs, inverted pyriform, µm wide, µm long, opening with inner pore and outer suture in superior position. Support cells appear similar to other vegetative cells. Oospores spherical to pyriform, smooth-walled, µm wide, µm long, usually filling oogonium. SPECIMENS: CHR A pro parte (microscope slide). REMARKS: Specimens agree well with published description (Mrozinska 1985), except that they are sometimes slightly larger. The oospores completely fill the oogonia, which is common in O. crispum. The small antheridia and thinner vegetative cells distinguish the specimens from f. obesum. DISTRIBUTION: South Canterbury: swamp on Monument Road (NZMG E, N). Cosmopolitan, but a new record for New Zealand. WATER QUALITY: Unknown. Group 5: monoecious, 2 spermatozoids derived by longitudinal division in parent cell 15. Oedogonium didymum Novis, sp. nov. Fig. 6N-O, 7S-W Monoecium. Cellulae vegetativae cylindricae vel subangustatae, µm latae, µm longae, ratione arithmetica longitudinis:latitudinis , tenuitunicatae, unicam pyrenoidem per cellulam continentes. Cellula basalis non visa. Antheridia µm lata, 6-7 µm longa, intercalaria, 2-5 in serie disposita, 2 spermatozoidia ex partitione longitudinali in cellula parentis exorta per antheridium continentia. Oogonia unica, sphericavel inverse pyriformia, tenuitunicata, µm lata, µm longa, ex sutura externa atque poro interno in positione superiore aperientia. Cellulae suffultoriae ut videtur cellulis aliis vegetativis similes. Oospora sphaerica, µm diametro, tenuitunicata. HOLOTYPE: New Zealand, Nelson, Brook River, A. Crowe, 8 January 2002, CHR B pro parte (microscope slide). FEATURES: Monoecious. Vegetative cells cylindrical to slightly tapered, µm wide, µm long, length: width , smooth-walled, each containing 1 pyrenoid. Basal cell not observed. Antheridia µm wide, 6-7 µm long, intercalary, 2-5 in series, each containing 2 spermatozoids arising from longitudinal division in parent cell. Oogonia single, spherical to inverted pyriform, smooth-walled, µm wide, µm long, opening with outer suture and inner pore in superior position. Support cells appear similar to other vegetative cells. Oospore spherical, µm diameter, smooth-walled. REMARKS: A new species is justified by the Fig. 6 Photomicrographs of Oedogonium spp. A-C, O. cf. capillare: A, female filament containing cylindrical oogonia; B, higher magnification view of oogonium with pore (arrowhead); C, chain of antheridia, one of which contains spermatozoids (arrowhead). D-F, O. gracilius: D, oogonium with opening (arrowhead); E, intercalary antheridia (arrowheads); F, detail of antheridium with paired spermatozoids (arrowhead). G-J, O. cymatosporum var. areoliferum: G, fertile filament showing oogonium and antheridia (arrowheads), each containing a single spermatozoid; H-J, ornamented oospores at differing optical sections (arrowhead in H indicates areolae). K, O. sp. aff. pyrulum. Arrowhead indicates antheridium containing a single spermatozoid. L, O. crispum var. crispum f. obesum. Antheridia (arrowhead) and oogonium with opening (arrow) are shown. M, O. crispum var. gracilescens with oogonium and antheridia (arrowhead). N, O, O. didymum: N, oogonium with opening (arrowhead); O, oogonium (arrowhead) and antheridia (arrow). Scale bars = 10 µm. Use scale 1 for A, C-E, K-N. Use scale 2 for remainder.

16 Novis Oedogonium in South and Chathams Islands 349

17 350 New Zealand Journal of Botany, 2003, Vol. 41 arrangement of spermatozoids (from a longitudinal division rather than a transverse one). Unfortunately this is the most difficult feature to observe, so this species could easily be confused with others, such as O. brevicingulatum C.C.Jao (Mrozinska 1985, p. 76, fig. 56), which have the alternative spermatozoid arrangement. The specific epithet refers to the paired spermatozoids, the orientation of which is critical in the identification. DISTRIBUTION: Nelson: Lower Brook River (NZMG E, N); Canterbury: Newton Stream at Esk confluence (NZMG E, N). WATER QUALITY: Conductivity 160 µs cm 1, ph 7.7, clarity 100% (no data available for Brook River). Group 6: dioecious, nanandrous, smoothwalled vegetative cells 16. Oedogonium braunii Kütz. var. grande Novis, var. nov. Fig. 7J-N, 8D Dioecium, nanandrum, gynandrosporum. Cellulae vegetativae cylindricae, µm latae, µm longae, ratione arithmetica longitudinis:latitudinis , tenuitunicatae, pyrenoidibus iam non distinctis. Cellula basalis tumida, 30 µm lata, 50 µm longa, retinaculo rhizoidali praedita. Antheridia 7-9 µm lata, 5-6 µm longa, 1-2 in serie disposita, externa, in filamentis nanandriorum insidentia. Oogonia unica, sphaerica vel subellipsoidea, tenuitunicata, µm lata, µm longa, ex sutura mediana curta aperientia. Cellulae suffultoriae subtumidae. Oospora sphaerica, µm diametro, tenuitunicata. Androsporangia µm lata, 9-12 µm longa. HOLOTYPE: New Zealand, Canterbury, Waihao River North Branch, P. Novis, 9 August 2001, CHR A pro parte (preserved specimen). FEATURES: Dioecious, nannandrous, gynandrosporous. Vegetative cells cylindrical, µm wide, µm long, length: width , smoothwalled, pyrenoids not distinguished. Basal cell swollen, 30 µm wide, 50 µm long, with rhizoidal holdfast. Antheridia 7-9 µm wide, 5-6 µm long, 1-2 in series, external, borne on dwarf male filaments. Spermatozoids not observed. Dwarf males 2-3 cells long, inverted pyriform, attaching to support cell of oogonium. Oogonia single, spherical to slightly ellipsoidal, smooth-walled, µm wide, µm long, opening with short median suture. Support cells slightly swollen. Oospore spherical, µm diameter, smooth-walled. Androsporangia µm wide, 9-12 µm long. REMARKS: The original Latin description of O. braunii (Kützing 1849) is difficult to interpret. However, shape of the specimens is in very close agreement with material ascribed to this species and illustrated by Hirn (1900, p , fig. XXXII: ) and Mrozinska (1985, p. 313, fig. 504), but the size of all features is larger than that described (O. braunii: vegetative cells µm wide, oogonia µm wide, oospore µm wide) except for some African specimens described by Hirn (1900, p. 197). These latter specimens should be placed in the new variety described here, the name of which refers to the size of the specimens. DISTRIBUTION: South Canterbury: Waihao River North Branch (NZMG E, N). WATER QUALITY: Conductivity 50 µs cm 1, ph 7.7, clarity 100%. 17. Oedogonium cyathigerum Wittr. var. laevis Novis, var. nov. Fig. 75A-F, 8A-C Dioecium, nanandrum, (?)idioandrosporum. Cellulae vegetativae cylindricae, µm latae, µm longae, ratione arithmetica longitudinis:latitudinis , tenuitunicatae, 3-8 pyrenoides continentes. Cellula basalis angustata, 26 µm lata, 140 µm longa, retinaculo simplici praedita. Antheridia interna, in filamentis nanandriorum insidentia. Oogonia unica vel didyma, sphaerica vel subellipsoidea, tenuitunicata, µm lata, µm longa, ex sutura externa atque poro interno in positione mediana aperientia. Cellulae suffultoriae tumidis, usque 60 µm latae. Oospora ellipsoidea vel oblonga, µm lata, µm longa, tenuitunicata. Androsporangia non visa. HOLOTYPE: New Zealand, Canterbury, unnamed Fig. 7 Oedogonium spp. A-F, O. cyathigerum var. laevis: A-E, fertile female (large) and male (small) filaments; F, basal cell. G-I, O. macrandrium var. hohenackerii. Fertile filaments (note one oogonium in G is collapsed). J-N, O. braunii var. grande: J, L-N, female (large) and male (small) filaments (note that J and L are the same filament); K, basal cell. O-R, O. platygynum var. novae-zelandiae. Fertile filaments (note blunt processes on oogonia). S-W, O. didymum. Fertile filaments (note vertical partitioning of spermatozoids in S, T). X-AC, O. wissmanii: X-AB, fertile material (note androsporangium (short cell) in AB); AC, basal cell. Scale bars = 10 µm. Use scale 2 for I, N, R. Use scale 1 for remainder.

18 Novis Oedogonium in South and Chathams Islands 351

19 352 New Zealand Journal of Botany, 2003, Vol. 41 stream on Kennedys Road, P. Novis, 29 August 2001, CHR B pro parte (microscope slide). FEATURES: Dioecious, nanandrous, (?)idioandrosporous. Vegetative cells cylindrical, µm wide, µm long, length: width , smoothwalled, containing 3-8 pyrenoids. Basal cell tapered, 26 µm wide, 140 µm long, with simple holdfast. Antheridia internal, borne on dwarf male filaments. Spermatozoids not observed. Dwarf males 1-2 cells long, cylindrical, attaching to oogonium or support cell. Oogonia single or in pairs, spherical to slightly ellipsoidal, smooth-walled, µm wide, µm long, opening with inner pore and outer suture in median position. Support cells swollen (up to 60 µm wide). Oospore ellipsoidal to oblong, µm wide, µm long, smooth-walled. Androsporangia not observed. REMARKS: Closely resembles O. cyathigerum (Mrozinska 1985, p. 459, fig. 770) in size and shape of both female filaments and dwarf males, with the important difference that the mature oospores are not ornamented. Based on these oospores alone, the taxon would have been assigned to O. borisianum. However, examination of dwarf males revealed internal antheridia, an important distinction with O. borisianum, in which the antheridia are external. The variety name refers to the smooth oospore wall. DISTRIBUTION: Canterbury: unnamed stream on Kennedys Road (NZMG E, N). A taxon identified as Oedogonium borisianum from Rotomahana, Bay of Plenty (Nordstedt 1888) appeared similar but lacked dwarf males and was slightly smaller. WATER QUALITY: Conductivity 480 µs cm 1, ph 6.8, clarity 52%. 18. Oedogonium macrandrium Wittr. var. hohenackerii (Wittr.) L.H.Tiffany Fig. 7G-I, 8E-G REFERENCES: Tiffany 1929, p. 75; Mrozinska 1985, p. 332, fig FEATURES: Dioecious, nanandrous, (?)idioandrosporous. Vegetative cells cylindrical, µm wide, µm long, length:width , smoothwalled, pyrenoids not distinguished. Antheridia 6-8 µm wide, 6-8 µm long, 1-2 in series, external, borne on dwarf male filaments. Spermatozoids not observed. Dwarf males 2-3 cells long, inverted pyriform, attaching to oogonium or one cell either side. Oogonia single, slightly to distinctly inverted pyriform, smooth-walled, µm wide, µm long, opening with inner pore and outer suture in superior position. Support cells appear similar to other vegetative cells. Oospore spherical, µm diameter, smooth-walled. Androsporangia not observed. SPECIMENS: CHR B pro parte (microscope slide). REMARKS: The specimens agree well with the published description (Tiffany 1929; Mrozinskal985), except for the location of androsporangia. The length of the vegetative cells agrees with the description of Tiffany (1929), who viewed this characteristic as the chief distinguishing feature of the variety. DISTRIBUTION: Canterbury: Hinds River at SH1 (NZMG E, N). Cosmopolitan, but a new record for New Zealand. WATER QUALITY: Unknown. 19. Oedogonium platygynum Wittr. var. novaezelandiae Hirn Fig. 75O-R, 8H-J REFERENCES: Nordstedt 1888, p. 12, fig. 1:14-15; Hirn 1900, p. 278, fig. XLVII:304; Mrozinska 1985, p. 381, fig FEATURES: Dioecious, (?)nanandrous, gynandrosporous. Vegetative cells capitellate, 5-7 µm wide, µm long, length:width Pyrenoids not visible. Basal cell not seen. Dwarf males not seen. (?)Androsporangia 5-7 µm wide, 4-6 µm long, 2-3 in series. Oogonia single, longitudinally compressed, µm wide, µm long, surrounded by a median ring of 7 blunt projections, opening with suture in sub-median position. Support cells appear similar to other vegetative cells. Oospores not seen. Fig. 8 Photomicrographs of Oedogonium spp. A-C, O. cyathigerum var. laevis: A, oogonium (arrow) and dwarf males (arrowhead indicates empty internal antheridium); B, oogonia in series; C, oogonium with pore visible (arrowhead). D, O. braunii var. grande. Dwarf male filament (arrow) and oogonium (arrowhead indicates opening). E-G, O. macrandrium var. hohenackerii: E, dwarf male filament (arrow) and oogonium (arrowhead); F, detail of oogonium showing opening (arrowhead); G, detail of dwarf male. H-J, O. platygynum var. novae-zelandiae: H, oogonium with external projections (arrowheads), obliquely oriented; I, projections in optical section; J, androsporangia. K, L, O. cf. wissmanii: K, filament showing andro sporangium (arrow) and submedian opening in oogonium (arrowhead); L, paired oogonia. Scale bars = 10 µm. Use scale 1 for A-E, K, L. Use scale 2 for F-J.

20 Novis Oedogonium in South and Chathams Islands I 353

21 354 New Zealand Journal of Botany, 2003, Vol. 41 SPECIMENS: CHR B pro parte (microscope slide), from a preserved sample, T. Worthy, 1978, held at CHR. REMARKS: This variety has been found only in New Zealand, and Nordstedt (1888), who collected the type material, also did not find dwarf males. The "androsporangia" described above could alternatively be antheridia containing single spermatozoids. Given that dwarf males are unknown in O. pulchrum Nordst. & Hirn, which has a similarly structured oogonium and was listed as "incomplete" by Mrozinska (1985), O. platygynum var. novaezelandiae should also be regarded as incomplete until more detailed study is possible. DISTRIBUTION: Pond draining peatland, Chatham Island. Found previously at Ohaeawai, Northland (Nordstedt 1888). WATER QUALITY: Unknown. Group 7: dioecious, nanandrous, undulatewalled vegetative cells 20. Oedogonium sp. aff. O. wissmanii Skinner Fig. 7X-AC, 8K, L REFERENCES: Skinner 1980, p. 261, fig. 3:3a-c. FEATURES: Dioecious, nanandrous, gynandrosporous. Vegetative cells undulate, 9-23 µm wide, µm long, length:width , 6-8 undulations per cell. Pyrenoids not visible (cell contents mostly absent). Basal cell smooth-walled, swollen, 14 µm wide, 44 µm long, with simple holdfast. Dwarf males not seen. Androsporangium 20 µm wide, 28 µm long, with undulate walls, 5 undulations per cell. Oogonia spherical to inverted pyriform, 1 4 in series, µm wide, µm long, opening with inframedian suture. Support cells swollen (up to 30 µm wide). Oospore spherical, µm diameter, smooth-walled. SPECIMENS: CHR B pro parte (microscope slide), from a preserved sample, T. Worthy, 1978, held at CHR. REMARKS: Identification to species depends on observation of androsporangia, which are smoothwalled in the very similar O. undulatum (Bréb.) A.Braun ex De Bary. Only one androsporangium was found, slightly different to that described by Skinner (1980) which has only two undulations per cell and is up to seven-celled. Dimensions of the New Zealand material are also slightly smaller than the type, which has, in addition, only four undulations per cell. The filaments probably break easily at the androsporangia during slide preparation. DISTRIBUTION: Chatham Island: pond draining peatland. Non-fertile undulate-walled Oedogonium (indeterminate without finding androsporangia): South Canterbury: Waihao River North Branch (NZMG E, N); Southland: stream near Te Anau (NZMG E, N). O. undulatum has been reported from Otago: Queenstown Hill Pond (Flint 1966), Lake Hayes (Burns & Mitchell 1974); Canterbury: Lake Sarah (Flint 1977); and Bay of Plenty: Lakes Rotokawau, Okataina, Rotoma (Thomasson 1974), Rotorua, and Okareka (Baars-Kloos 1976). However, it is impossible to distinguish these records from O. wissmanii. WATER QUALITY: Unknown for Chathams sample; other samples conductivity µs cm 1, ph , clarity %. Group 8: indeterminate species Fertile filaments were found, which could not be identified to species level, from the following Nelson sites: Kaituna River at Sollys Road (NZMG E, N); Lee River at Meads Bridge (NZMG E, N); Anatoki River at road bridge (NZMG E, N). DISCUSSION Only 29% of samples containing Oedogonium could be identified below genus, owing to the absence of fertile material (Table 2). Usually female material was easier to find than male material, partly because oogonia are much larger and therefore more readily visible than antheridia. Fertile female material can sometimes be identified with confidence without male filaments (e.g., O. pringsheimii cf. var. nordstedtii, the oogonia of which are distinctively pyriform); however, no identifications could be made on the few occasions when male material only was present. The difficulty of finding fertile specimens is not restricted to New Zealand; undoubtedly there are many Oedogonium species worldwide that have never been recognised. A much higher proportion of specimens from Canterbury became fertile than from other areas (Table 2), but why this should be so is unclear. Perhaps conditions in the incubator more closely resembled the environmental conditions that trigger sexual reproduction in this part of the country, or

22 Novis Oedogonium in South and Chathams Islands 355 perhaps the drier climate of eastern Canterbury selects for taxa with greater propensity to form zygospores. The conditions determining when the sexual cycle will occur may be different for each species, since different species may have different requirements in culture (Rawitscher-Kunkel & Machlis 1962). Not all species in a sample will become fertile simultaneously. Some Oedogonium species require the presence of bacteria in cultures in order to reproduce sexually (Machlis et al. 1974). Generally, the finer filamentous taxa more readily became fertile than the larger ones, and fewer nanandrous than macrandrous species were found. The latter point reflects worldwide findings: Mroziriska (1985) described 283 macrandrous species and 161 nanandrous species (not counting those listed as "incomplete"). A greater diversity of Oedogonium probably occurs in swamps, lakes, and tarns. The present study of streams was stimulated by current interest in using periphyton for monitoring of water quality (Biggs & Kilroy 2000). Oedogonium clearly has low potential as a bioindicator at the species level, because the fertile structures needed for identification are seldom present in field material. Also, the diversity of the genus is so great that factors determining the distributions of different species could be extremely complex, beyond physical or chemical characteristics of the habitat. Most species were so seldom detected that sensible comment relating their distributions to water quality is not possible. Some collecting sites were visited twice, but the majority only once. Given that different species appear to undergo sexual reproduction under different conditions, the full complement of Oedogonium species at most sites is probably still undescribed. Twelve of the 20 taxa were found only once during the survey. It is most unlikely that this represents their true geographical range in New Zealand, particularly when some species were found in two sites very distant from each other (e.g., Oedogonium didymum, found in the Brook River, Nelson, and Newton Stream in the Canterbury foothills). More samples from a greater geographic range would further our understanding of distribution patterns, and would undoubtedly reveal more species. Many species have been described and named in the absence of male material (e.g., O. pseudomitratum, O. plurisporum Arnoldi & Y.V.Roll, O. uleanum Hirn). However, I found that some taxa differ most markedly in features of the male filaments, such as internal antheridia or width of the male filaments, when features of the female filaments were not conclusive enough to separate them. An example was Oedogonium cyathigerum var. laevis, where in the absence of dwarf males (which contained internal antheridia) the taxon would have been assigned to O. borisianum. It follows that new species descriptions that do not contain information on male filaments may be of limited use to subsequent workers. A complex series of chemical signals controls the development of androsporangia, oogonia, and dwarf males in nanandrous species. Consequently, mature oogonia will not develop in the absence of dwarf males (Graham & Wilcox 2000). However, this does not necessarily justify an assumption that fertile material lacking males is macrandrous. A sample from the Chatham Islands, collected and preserved in 1978, contained O. cf. wissmanii with mature oospores. This undulate-walled species is known to be nanandrous (Skinner 1980), but dwarf males were not visible. However, after considerable searching, a single androsporangium was found (Fig. 8K). Some dwarf males are extremely delicate and can be lost in preparation or over time. Many species of Oedogonium are distinguished by size of filaments and oogonia (Mrozinska 1985). As in Spirogyra Link, this has resulted in large tallies of species. However, polyploid strains have now caused some traditional species concepts in Spirogyra to be questioned. Clonal cultures of Spirogyra filaments of initially uniform width produced filaments of four significantly different widths following a series of crosses (Hoshaw et al. 1985). This suggests that the number of species of Spirogyra is actually much lower than the number recognised at present. Polyploidy is known in Oedogonium: haploid and diploid strains occur and polyspermy (fusion of more than one haploid spermatozoid with a haploid egg cell) has been observed (Hoffman 1973a; Mrozinska 1985). Experimental work would be required to determine whether polyploidy could have influenced identifications in the present study. The O. pringsheimii and O. crispum species complexes would be prime candidates for investigation. Work on Oedogonium shows how keys and descriptions of algae from the Northern Hemisphere must be used very carefully in studies of Australasian material. For example, O. cyathigerum var. laevis would have been identified as O. borisianum in the absence of antheridia. It is possible that parts of the algal flora of Australasia have evolved in parallel with floras elsewhere: Oedogonium species found in

23 356 New Zealand Journal of Botany, 2003, Vol. 41 this survey are a mixture of cosmopolitan species and apparent endemics. This is true of other New Zealand algae, for example, the desmid flora (Croasdale & Flint 1986, 1988; Croasdale et al. 1994). Future taxonomic study in Australasia, hopefully involving molecular comparisons with Northern Hemisphere species, is likely to provide new insights into algal evolution, dispersal, and distribution. Phylogenetic placement of the Oedogoniales within the Chlorophyta is still unclear. Stephanokont zoospores are also produced by members of the class Bryopsidophyceae (as defined by Van den Hoek et al. (1995)), but the structure of their flagellar basal apparatus clearly differs from Oedogonium. The distinct transverse striation in the basal structure of Oedogonium flagella is regarded as analogous to those found in chlorophycean basal body connectives (Van den Hoek et al. 1995). In addition, Oedogonium displays other chlorophycean features such as production of a phycoplast during cell division (Pickett-Heaps 1975). Molecular phylogenetic approaches have confirmed the monophyly of the Oedogoniales, but have failed to elucidate the evolutionary position of the order within the Chlorophyceae (Booton et al. 1998; Buchheim et al. 2001). The development of paired spermatozoids in a single antheridial cell is thought to be the first major evolutionary divergence within Oedogonium (Mrozinska 1991). This implies that some features, such as dwarf males, have arisen more than once during evolution of the genus. Since dwarf male filaments are also found in Oedocladium and Bulbochaete, the advent of double spermatozoids could also predate the development of branching in these genera, but confirmation of this would require detailed molecular investigation. In the diatoms, evolutionary diversification has taken place predominantly in sexual lineages (Mann 1999). Reliance on sexual reproduction to avoid unfavourable conditions could have led to the great richness of Oedogonium species. The onset of drying in crude cultures seems to induce fertility in many species, and other authors have found depletion of nutrients (Rawitscher-Kunkel & Machlis 1962), especially nitrate (Hill & Machlis 1970; Machlis et al. 1974), to be necessary to stimulate gametogenesis in cultured strains. Raising the free CO 2 level in the induction medium may also be successful for this purpose, though reduction of nutrients may still be necessary (Hoffman 1973b). Presence of bacteria in culture media may increase the fertility rate of Oedogonium dramatically (Machlis 1973); these could trigger gametogenesis in the algae by depleting nutrients and increasing CO 2, since experiments with the addition of filtrates from the bacterial cultures gave a negative result. All these methods could mimic the onset of unfavourable conditions in the field. Zygospores may be the only cell type that survives such conditions. Thus, sexual reproduction may be frequently enforced in these algae, as in those diatom groups that reproduce sexually. Zygnematalean filaments such as Spirogyra and Zygnema Agardh, also with vast numbers of species (e.g., Transeau 1951; Randhawa 1959) and producing resistant stages sexually, could have diversified in a similar way. However, there seems to be an important difference in distribution patterns of Oedogonium and Spirogyra: the former was not found in streams near the Main Divide (Fig. 1) where Spirogyra frequently dominated. Hut Creek (Ryton Station) was the closest Canterbury stream to the Main Divide (approximately 35 km away) in which Oedogonium was found. Oedogonium commonly occurs in wetlands on Bealey Spur, a short distance from the Main Divide (C. Kilroy pers. comm. 2002), so its absence in streams in this area may result from high water speed and disturbance frequency. Flooding has a serious effect on stream benthos (Biggs et al. 1997; Jowett & Biggs 1997; Francoeur et al. 1998). Water flow and disturbance have profound implications for Oedogonium, because its life cycle relies on flagellated cells (zoospores, androspores, and spermatozoids). By contrast, flagellated cells are absent from the Zygnematales and sexual reproduction occurs by conjugation. ACKNOWLEDGMENTS P. Broady (University of Canterbury), E. A. Flint, C. Bezar, and I. Breitweiser (Landcare Research), S. Skinner (Royal Botanic Gardens, Sydney), and an anonymous reviewer provided valuable comments on the manuscript. I sincerely thank R. Smith (Tasman District Council), A. Crowe (Cawthron Institute), T. James, D. Cottam, and M. Kennedy (West Coast Regional Council), C. Kilroy (National Institute of Water and Atmospheric Research), S. Hayward (Environment Canterbury), K. Hamill (Environment Southland), and G. Stephenson (Wellington Regional Council), who posted samples to me from different areas of New Zealand. R. Buxton, M. Dawson, and H. Rhodes provided excellent field and technical assistance, and I am grateful to landowners (too many to name) for granting access to collecting sites. I thank P. M. Eckel, Buffalo Museum of Science, New York, for the Latin translations. This work was supported by a Landcare Research Investment Postdoctoral Fellowship.

24 Novis Oedogonium in South and Chathams Islands 357 REFERENCES Baars-Kloos, J. 1976: Phytoplankton in Lake Rotorua and Lake Okareka and its interaction with macrophytes. Unpublished PhD thesis, University of Waikato, Hamilton, New Zealand. 152 p. Biggs, B. J. F.; Kilroy, C. 2000: Stream periphyton monitoring manual. Christchurch, NIWA. 226 p. Biggs, B. J. F.; Kilroy, C. 2002: Use of the SHMAK clarity tube for measuring water clarity: comparison with the black disk method. New Zealand Journal of Marine and Freshwater Research 36: Biggs, B. J. F.; Price, G. M. 1987: A survey of filamentous algal proliferations in New Zealand rivers. New Zealand Journal of Marine and Freshwater Research 21: Biggs, B. J. F.; Duncan, M. J.; Francoeur, S. N.; Meyer, W. D. 1997: Physical characterisation of microform bed cluster refugia in 12 headwater streams, New Zealand. New Zealand Journal of Marine and Freshwater Research 31: Biggs, B. J. F.; Kilroy, C.; Mulcock, C. M. 1998: New Zealand stream health monitoring and assessment kit. Stream Monitoring Manual. Version 1. NIWA Technical Report p. Booton, G. C.; Floyd, G. L.; Fuerst, P. A. 1998: Origins and affinities of the filamentous green algal orders Chaetophorales and Oedogoniales based on 18S rrna gene sequences. Journal of Phycology 34: Brand, F. 1911: Über einige neue Grünalgen aus Neuseeland und Tahiti. Deutsche Botanische Gesellschaft Berichte 29: Buchheim, M. A.; Michalopulos, E. A.; Buchheim, J. A. 2001: Phylogeny of the Chlorophyceae with special reference to the Sphaeropleales: a study of 18S and 26S rdna data. Journal of Phycology 37: Burns, C. W.; Mitchell, S. F. 1974: Seasonal succession and vertical distribution of phytoplankton in Lake Hayes and Lake Johnson, South Island, New Zealand. New Zealand Journal of Marine and Freshwater Research 8: Croasdale, H.; Flint, E. A. 1986: Flora of New Zealand: Desmids. Vol. I. Wellington, Government Printer. 133 p. Croasdale, H.; Flint, E. A. 1988: Flora of New Zealand: Desmids. Vol. II. Christchurch, Botany Division, DSIR. 147 p. Croasdale, H.; Flint, E. A.; Racine, M. M. 1994: Flora of New Zealand: Desmids. Vol. III. Lincoln, Manaaki Whenua Press. 218 p. Flint, E. A. 1966: Additions to the checklist of freshwater algae in New Zealand. Transactions of the Royal Society of New Zealand, Botany 3: Flint, E. A. 1977: Checklist of the flora of Cass. In: Burrows, C. J. ed. Cass. History and science in the Cass district, Canterbury, New Zealand. Christchurch, University of Canterbury. Pp Francoeur, S. N.; Biggs, B. J. F.; Lowe, R. L. 1998: Microform bed clusters as refugia for periphyton in a flood-prone headwater stream. New Zealand Journal of Marine and Freshwater Research 32: Gauthier-Lièvre, L. 1963: Oedogoniacées Africaines. Planches. Nova Hedwigia 6(3-4): Gauthier-Lièvre, L. 1964: Oedogoniacées Africaines. Nova Hedwigia 7(1-2): Graham, L. E.; Wilcox, L. W. 2000: Algae. Upper Saddle River, NJ, Prentice Hall. 640 p. Hill, C. F. 1970: New algal records from New Zealand freshwater habitats. (1) Phytoplankton (2) Filamentous algae. Unpublished New Zealand Electricity Department report. Available from Energy Library and Information Services Limited, Wellington, New Zealand. 9 p. Hill, G. J. C.; Machlis, L. 1970: Defined media for growth and gamete production of the green alga Oedogonium cardiacum. Plant Physiology 46: Hirn, K. E. 1900: Monographie und Iconographie der Oedogoniaceen. Acta Societatis Scientiarum Fennicae 27: Hoffman, L. R. 1973a: Fertilisation in Oedogonium. II. Polyspermy. Journal of Phycology 9: Hoffman, L. R. 1973b: Fertilisation in Oedogonium. I. Plasmogamy. Journal of Phycology 9: Hoshaw, R. W.; Wang, J.-C.; McCourt, R. M.; Hull, H. M. 1985: Ploidal changes in clonal cultures of Spirogyra communis and implications for species definitions. American Journal of Botany 72: Jao, C. C. 1934: Oedogonium in the vicinity of Woods Hole, Massachusetts. Rhodora 36: Jao, C. C. 1979: Monographia Oedogoniales Sinicae. Beijing, Sci. Press. Jowett, I. G.; Biggs, B. J. F. 1997: Flood and velocity effects on periphyton and silt accumulation in two New Zealand rivers. New Zealand Journal of Marine and Freshwater Research 31: Kützing, F. T. 1843: Phycologia generalis oder anatomie, physiologie, und systemkunde der tange. Leipzig, F. A. Brockhaus.

25 358 New Zealand Journal of Botany, 2003, Vol. 41 Machlis, L. 1973: The effects of bacteria on growth and reproduction of Oedogonium cardiacum. Journal of Phycology 9: Machlis, L.; Hill, G. C.; Steinback, K. E.; Reed, W. 1974: Some characteristics of the sperm attractant in Oedogonium cardiacum. Journal of Phycology 10: Mann, D. G. 1999: The species concept in diatoms. Phycologia 38: Mrozińska, T. 1985: Oedogoniophyceae: Oedogoniales. In: Pascher, A.; Ettl, H.; Gerloff, J.; Heynig, H.; Mollenauer, D. ed. Süsswasserflora von Mitteleuropa 14. Jena, Gustav Fischer Verlag. 624 p. Mrozińska, T. 1991: A preliminary investigation of the taxonomic classification of the genus Oedogonium Link (Oedogoniales) based on the phylogenetic relationship. Archiv für Protistenkunde 139: Nordstedt, O. 1888: Freshwater algae collected by Dr S. Berggren in New Zealand and Australia. Kongl. Sveshka vetenskaps-akademiens handlingar 22(8). 98 p. Pickett-Heaps, J. D. 1975: Green algae: structure, reproduction and evolution in selected genera. Sunderland, Massachusetts, Sinauer. 606 p. Randhawa, M. S. 1959: Zygnemaceae. New Delhi, Indian Council of Agricultural Research. 478 p. Rawitscher-Kunkel, E.; Machlis, L. 1962: The hormonal integration of sexual reproduction in Oedogonium. American Journal of Botany 49: Scott, A. M.; Prescott, G. W. 1958: Some freshwater algae from Arnhem Land in the Northern Territory of Australia. In: Specht, R. L.; Mountford, C. P. ed. Records of the American-Australian scientific expedition to Arnhem Land 3: botany and plant ecology. Melbourne, Melbourne University Press. Pp Skinner, S. 1980: New records of Zygnemaphyceae and Oedogoniophyceae (Chlorophyta) from northern New South Wales. Proceedings of the Linnean Society of New South Wales 104: Skuja, H. 1976: Zur Kenntnis der Algen neuseeländischer Torfmoore. Nova Acta Regiae Societatis scientiarum Upsaliensis, Series V.C. 2: Thomasson, K. 1974: Rotoruaphytoplankton reconsidered (North Island of New Zealand). Internationale Revue der gesamten Hydrobiologie 59: Tiffany, L. H. 1929: A key to the species, varieties, and forms of the algal genus Oedogonium. The Ohio Journal of Science 29: Tiffany, L. H. 1948: Oedogonium chapmanii sp. nov. from New Zealand. Natural History Miscellanea of the Chicago Academy of Sciences 16: 1-4. Transeau, E. N. 1951: The Zygnemataceae. Columbus, The Ohio State University Press. 325 p. Van den Hoek, C.; Mann, D. G.; Jahns, H. M. 1995: Algae: an introduction to phycology. Cambridge, Cambridge University Press. 623 p. Wittrock, V. B. 1872: Oedogoniaceae novae, in Suecia lectae. Botaniska Notiser 1: 1-8. Wittrock, V. B. 1878: Oedogoniaceae Americanae, huiusque cognitae. Botaniska Notiser 5: