Muelleria 14:99 (2000) Spirogyra cardinia (Zygnemataceae, Zygnematophyceae, Chlorophyta): a new species offreshwater alga from Victoria,Australia. Simon H. Lewis1 and TimothyJ. Entwisle2 1 National Herbarium ofVictoria, Royal Botanic Gardens Melbourne, BirdwoodAvenue, South Yarra 3141, Australia. 2Royal Botanic Gardens Sydney, Mrs Macquaries Road, Sydney, 2000, Australia. Abstract Spirogyracardinia (Zygnemataceae,Chlorophyta), anew speciesoffreshwateralgafromVictoria, Australia, in Section Conjugata (Vaucher) Hansg., Punctata-Group (Kadlubowska 1984) fromthe CardiniaReservoirareain south-easternVictoria, is described and illustrated. Itis morphological- ly similartoS. bellis (Hassall) Cleve (whichis in theMaxima-Group (Kadlubowska 1984)) andS. occidentalis (Transeau) Czurda (which is in the Punctata-Group (Kadlubowska 1984)) but differs inchloroplastnumberandvegetativefilamentand zygospore dimensions. Introduction Our recent census from literature records (Lewis & Entwisle 1998) accepted 31 species of Spirogyra Link from Australia, while Kadlubowska (1984), in the latest worldwide monograph of the genus, recognized 386 species in total. Since Kadlubowska’s mono- graph, more than 30 new species have been described from around the world, yet none were fromAustralia. This paper describes a new species discovered as part ofAustralia- wide collecting for the preparation of an account of Zygnemataceae for the Algae of Australia project. Methods Preparation ofMaterial Specimens were preserved initially in 5% commercial formalin. After preparing dried specimens and permanent microscope mounts, the remaining material was transferred to 70% ethanol with 5% glycerol. For the microscope slides, specimens were stained with 1% aniline blue and placed in 10% Karo corn syrup with 0.25% phenol then mounted in 40% Karo corn syrup with 0.25% phenol. Taxonomy Spirogyra cardinia S.H. Lewis, sp. nov. Cellulae vegetativae 42-156 pm longae, 66-75 pm latae, parietes extremi plani; chloroplasti 1(—2) anfracti 2-6-plo in cellulis; pyrenoides 5-15, 6 pm latae. Conjugatio scalariformis,canalibus ab utrinquecellulis formatis, extremitatibus tumidis. Gametangia (et cellulae sterilis aliquot) in latera conjugationis inflata (75-90 pm latae) abbreviata plerumque. Zygosporae ellipsoidea uniformes, 63-76 pm longae, 36-48 pm latae, exospora laeve incolorata, mesosporapuncticulosa (punctula ad 1.5 pm lata), aurea. Type: Australia, Victoria, Narre Warren East, small pool near Kangaroo Flat Picnic Area, in Cardinia Reservoir Park. S.H.Lewis 403, 20.v.1998 (holotype MEL 2046440: isotype NSW). Vegetative cells 42-156 pm long, 66-75 pm in diameter, length to diameter ratio = 1.15, with plane end walls; chloroplasts l(-2), making 2-6 turns; pyrenoids 5-15, up to 6 pm in diameter. Conjugation scalariform,conjugationtubesformed equally byboth gametan- 100 S.H. Lewis andT.J. Entwisle giaand swollen where they meet; gametangia(and some sterilecells) inflatedon the con- jugation side to 75-90 pm and often shorter than the vegetative cells. Zygospores ellip- soid, uniform, 63-76 pm long, 36^48 pm in diameter, length to diameter ratio = 1.78, exospore smooth and colourless, mesospore finely punctate and golden brown to yellow, pits to 1.5 pm in diameter. Diagnostic Features-. Spirogyra cardinia belongs in the section Conjugata on the basis of its plane walls, and in the Punctata-Group on account of the mostly single chloroplast per cell and ornamented mesospore (Kadhibowska 1984). It differs from all other species in this group by having broader filaments (see Table 1 and Fig 1 ). In this group, S. cardinia is most similar to S. occidentalis (Transeau) Czurda in zygospore size (50-105 pm long, 36-61 pm in diameter in that species). However, S. occidentalis has much narrower vegetative cells (40-54 pm in diampter, although Czurda (1932 p.183, quoted in Kadhibowska 1984, p. 342) describes ‘swollen barrel-shaped’ cells) and gametangia that are cylindric or only inflated up to 66 pm. The orientation of the zygospores in S. occidentalis is parallel to the main axis, while that ofS. cardinia is at 45-90 degrees, with only some parallel. From the illustrations ofS. occidentalis, the new species also appears to have considerably shorter fertile and sterile cells. Spirogyra cardinia is also comparable to S. bellis (Hassall) Cleve, from the Maxima- Group, a group comprising species with two or more chloroplasts and sculptured zygospore walls. The new species occasionally has cells with two chloroplasts, and S. bellis has similar vegetative filament dimensions. Spirogyra bellis however, has 5-7 , chloroplastspercell and they are more spiralled (2-6 turns percell cf. I). It alsohas larg- erzygospores (64-105 pm long, 45-70 pm in diameter; Kadhibowska 1984) that are glo- bose or lenticularrather than ellipsoid, the conjugation tubes are not swollen at the ends, and thegametangia are usually swollen on both sides orenlarged. No otherspecies in the Maxima-Group are likely to be confused with S. cardinia. Spirogyra rugulosa Iwanoff, in the Punctata-Group, is superficially very similar to the new species but the conjugation tubes are clearly formed by the male gametangiaand the zygospores are broader. A recent collection {S.H.Lewis 718 (MEL)) from the type locality ofSpirogyra cardinia has been referred to S. rugulosa. In this collection the wall was not as obviously punctate as that of the new species, although the vegetative fila- ments were similarly large. The conjugation tubes were, however, all definitely formed Table 1. Comparison ofSpirogyra cardinia with similar taxa and groups mentioned in the text. Datafrom Kadhibowska 1984 and current study. Taxon Veg. cells Zygospores Zygospores Chloroplast Tubes diam. pm diam. pm length pm No. formed by S. cardinia 66-75 35—48 63-76 1(—2) both gametangia /JM/ictata-Group 1 1-62 19-68 26-150 1(—3) varies S. rugulosa Iwanoff 45-62 45-55 27-90 1 male (Kadhibowska 1984) gametangia rugulosa 63-78 42-48 66-78 male .S', 1 (S.H.Lewis 718) gametangia S. occidentalis 40-54 36-6! 50-105 1-3 both (Transeau) Czurda gametangia S. bellis 65-80 45-70 64-105 5-6 both (Hassall) Cleve gametangia Spirogyra cardinia 101 Figure 1 a-c Spirogyra cardinia sp. nov.\ a. vegetative cells; b. zygospores showing mesospore ornamentation visible in transverse section (T) and surface view through exospore (S); c. conjugatingcells. Scale: 40pm. by the malegametangiaand therefore matched those ofS. rugulosa whereas the tubes of , the new species wereall obviously formed by both gametangia. Both ofthese populations warrantfurther study. TheDipsotorlibwuatsionabaonudt H3a0bictmatd:eSeppiraongdyr3a mcaridnindiiaamisetoenrlyankdnoawppnarfernotmlythpeertympaenecnotl.lecOttihoenr. collections from the same site, at the same time and at similartimes in the following year, yielded a number of other species of Spirogyra, none of which resembled S. cardinia. Spirogyra cardinia was loosely associated with Callitriche stagnalis Scop., Cyperus era- grostis Lam. and C. lucidus R.Br., and with Nitella leptostachys A.Br. var. leonhardii (R.D.Wood) R.D.Wood. Etymology. The epithet refers to the location from which it was collected. Conservation Status: Using the criteria of Briggs and Leigh (1996) the Risk Code is assessed at IK. Based on current collecting it is clearly rare, however, as with all the ephemeral Zygnemataceae, it may be widespread. Making decisions regarding the con- servation status ofalgae in Australia is especially difficult due to a lack ofdistributional data, paucity of fertile (needed for identification) collections, changes to the fragile aquatic environments (Entwisle 1997) and the transient nature ofSpirogyra. 1 102 S.H. Lewis and T.J. Entwisle Discussion Although this species is differentiated from the other species in the Punctata-Group (Kadfubowska 1984) by its vegetative cell dimensions, acharacter viewed as being influ- enced by polyploidy (Hoshaw et al. 1985, 1987; Hoshaw and McCourt 1988), this dif- ference appears to be of such magnitude that the entity deserves to be recognized taxo- nomically. Furthermore, it differs from the most similar species, such as Spirogyra bellis, S. rugulosa and S. occidentalis, by a number ofcharacters apparently less influenced by polyploidy, such as spore, gametangiaand tube shape, chloroplast numberand mesospore ornamentation. Acknowledgments We would like to thank ABRS for funding the project, staff at MEL, Neville Walsh for correcting the Latin diagnosis and Emma Lewis for extensive support and help with field work. References Briggs, J.D., and Leigh, J.H. (1996). ‘Rare or threatened Australian plants', 1995 revised edn. (CS1RO: Collingwood.) Czurda,V. (1932). Zygnemales. In ‘Die Siisswasserflora von Mitteleuropa’Vol. 9, (EdA. Pascher) (Gustow-Fischer: Jena). Entwisle, T.J., (1997). Algae. In ‘A conservation overview of Australian non-marine lichens, bryophytes, algae and fungi". (G.A.M. Scott.T.J. Entwisle, T.W. May and G.N. Stevens, eds.), pp. 34-48 (EnvironmentAustralia: Canberra). Hoshaw, R.W., Wang, J.C., McCourt, R.M., and Hull, H.M. (1985). Ploidal changes in clonal cul- tures of Spirogyra communis and implications for species definitions. American Journal of Botany72(7), 1005-11. Hoshaw, R.W., and McCourt, R.M. (1988). The Zygnemataceae (Chlorophyta) a twenty-year update ofresearch. Phycologia 27(4), 51 1-48. Kadlubowska, J.Z. (1984). ‘Siisswasserflora von Mitteleuropa. Conjugatophyceae Chlorophyta VIII, Zygnemales' Band 16. (Eds H. Ettl. J. Gerloff, H. Heynig, D. Mollenhauer) (Gustav FischerVerlag: Stuttgart, NewYork). Lewis, S.H.. and Entwisle,T.J. (1998).Zygnemataceae (Chlorophyta) inAustralia: a Reassessment ofRecords and a Key toAcceptedTaxa. Muelleria 1 , 51-93.