Fottea 12(1): 95–110, 2012 95

Desmids from () and adjacent peat bogs

Alfred van Ge e s t 1 & Peter Co e s e l 2

1 De Wittenkade 156, NL–1051 AN Amsterdam, The Netherlands 2 Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, Postbus 94248, NL–1090 GE Amsterdam, The Netherlands

Abstract: In 2006 the desmid flora of Lake Nabugabo and some adjacent peat bogs was studied. All in total some 108 taxa were identified. Fourteen taxa, most of them being only known from the African continent, are discussed in detail. Six taxa are newly described: Euastrum gemmatum var. quadrituberosum, Micrasterias stuhlmannii var. nabugabonum, Cosmarium nabugabonum, Xanthidium thomassonii, Staurodesmus eckertii var. africanus and Staurastrum capitulum var. foersteri. The morphological variation found in Staurastrum longicolle is discussed in the light of possible speciation of desmids in a limnetic environment.

Key words: new desmid taxa, Uganda, diversity, ecology, plankton

Introduction were designated as a RAMSAR–site (protected area). At this moment the lake is still used for In July 2006 the first author visited Lake Nabugabo fishery and the area around it for grazing cattle in Uganda (East Africa) to collect samples for a and crop cultivation (Ramsar 2003). taxonomic and biogeographical study of desmids. For two reasons this lake is interesting for This shallow lake lies almost exactly on the collecting desmids. The first reason is that the equator, about 100 km south–east of Kampala, lake is surrounded by a boggy area with a vast the capital of Uganda. It is a satellite lake of Lake vegetation of peat moss (Sphagnum). In Europe and Victoria and separated from this lake by a sand North–America Sphagnum–dominated habitats bar of only 2 km wide. The size is approx. 5 by 8 are widespread and thoroughly investigated. km. Situated at an altitude of approx. 1140 m it is Co e s e l & Me e s t e r s (2007) who distinguish five more or less between lowland and the mountain different desmid communities for the Netherlands region but the climate is still tropical. The average recognize even a separate community for this minimum temperature for this part of Uganda does type of habitat. In tropical lowlands, however, not drop below 15 ºC and the average maximum these areas are very rare (Va n Br e e m e n 1995). temperature fluctuates year round very little This can be the reason of the low number of between 25 and 30 ºC (Ch e n g 2006). publications dealing with tropical Sphagnum– The lake has been isolated from Lake inhabitating algae, but it can also have to do with Victoria for several thousands of years and hosts the preferences of hydrobiologists to sample a few fish species that are not found in Lake large water bodies instead of shallow pools. It Victoria. The lake as well as the surrounding is not ruled out that desmid species described in swamps are poor in nutrients and support a high taxonomic publications can originate from these diversity of species. Lake Nabugabo is one habitats but that this is not explicitly mentioned of the few places in Uganda where swimming is in the text. popular as the lake has a reputation of being free of The special status of Lake Nabugabo is also Schistosomiasis (Bilharzia). This is often related to emphasized by its phytoplankton composition. An the scarcity of molluscs that act as an intermediate analysis that was carried out in 2004 revealed that host of this parasite. It could be connected to the the plankton was dominated primarily by desmids, low level of ions, especially calcium, which is while the plankton of 10 other satellite lakes of needed by molluscs for the development of their was dominated by cyanobacteria calcareous shells (Ef i t r e et al. 2001; Ch a p m a n et (Kl i n g et al. 2006). Actually, most desmid al. 2001). In 2004 the lake and its surroundings species are benthic organisms and prefer densely 96 van Ge e s t & Co e s e l : Desmids from Lake Nabugabo vegetated water bodies. Some species, however, et al. (2001) give values between pH 6.0 and pH 7.1 can lead a more or less free–floating existence due for the lake water and Li n d (1971) a pH 5.8 for the to the movement of water (tychoplankton) but will swampy soil beside the road from to , settle down as soon as water turbulence decreases. north of Lake Nabugabo. Ef i t r e et al (2001) give an Euplanktonic species are a rarity among desmids average depth of the lake bottom of 4.5 m. and a water transparency of 0.5–0.8 m. On the (windy) visit of (Br o o k 1981) and lake plankton quantitatively Lake Nabugabo by the first author, the bottom was not dominated by desmids is but incidentally met visible. with. Due to manmade eutrophication of lakes throughout the world, phytoplankton that consists Specification of the samples: mainly of desmids is becoming even rarer; 2007–015, Lat. 0° 20’ 38.5” S, Long. 31° 53’ 11.6” E, therefore collecting plankton samples from Lake net sample Nabugabo was a second good reason to visit this 2007–016, Lat. 0° 20’ 38.5” S, Long. 31° 53’ 11.6” E, site. net sample There are hardly any published references 2007–017, Lat. 0° 20’ 38.5” S, Long. 31° 53’ 11.6” E, submerged roots of reed to the desmid flora of this lake. Li n d (1971) 2007–018, Lat. 0° 20’ 37.4” S, Long. 31° 53’ 05.2” E, sampled swampy sites beside the road from Sphagnum Masaka to Bukakata near Lake Nabugabo, but 2007–019, Lat. 0° 20’ 37.4” S, Long. 31° 53’ 05.2” E, does not mention plankton samples from the Sphagnum lake itself or samples taken from Sphagnum– 2007–020, Lat. 0° 20’ 37.4” S, Long. 31° 53’ 05.2” E, dominated habitats. Other papers on Lake Sphagnum Nabugabo are mainly focussed on fish species in 2007–021, Lat. 0° 20’ 22.5” S, Long. 31° 53’ 26.1” E, relation to fishery and a small minority refer to Sphagnum macrophytes. One publication (Ef i t r e et al. 2001) 2007–022, Lat. 0° 20’ 23.1” S, Long. 31° 53’ 26.5” E, deals with macroinvertebrates and does provide Sphagnum some ecological information that can be relevant The scanning electron microscopy (SEM) images for further desmid research. The present paper have been made with the use of a Phenom desktop describes the desmid flora of both the proper lake microscope. Sample material was placed on glass and the adjacent Sphagnum bogs. A number of coverslips that were coated three times with a 10% species is taxonomically and biogeographically solution of poly–L–lysine. After dehydration in aceton discussed in more detail. series (30%, 50%, 70%, 2×90%, 2× 95%, 2× 100%)

the material was dried with liquid CO2 and sputter– coated with gold. Material and Methods

Sampling sites were located at the northern shore of Lake Nabugabo (Fig. 1). Plankton samples were collected with a plankton net (mesh size 50 µm) from a small boat, about 50 meters from the shore. Benthos samples where gathered by squeezing submerged Sphagnum by hand and catching the residue in a small bottle. This moss was taken from a small boggy zone of Sphagnum just behind a zone of high grasses that fringed the lake shore. One sample was taken by squeezing out the roots of reed–like grasses that contacted the lake water. Samples were fixed with formaldehyde to a final concentration of about 4% on the day of collection, but some fresh samples were brought back to the Netherlands for studying the live content. Geographic co–ordinates were recorded with a GPS (which also measured a height of 1137–1142 m). Conductivity of the water sampled was measured with a simple portable meter and a conductivity of 10– 30 μS.cm–1 was measured for all samples (10 μS.cm–1 being the lowest measurable value of the meter). In the Fig. 1. Map of Africa, Lake Victoria and the sampling site present investigation acidity was not measured. Ef i t r e location. Fottea 12(1): 95–110, 2012 97

Results but the fact that all specimens stayed neatly on a certain distance from each other is probably due Analysis of the two samples taken with a net from to this envelope. Benthic species, for that matter, the main body of Lake Nabugabo shows that can also have gelatinous envelopes. desmids are indeed the most dominant organisms Analysis of the four Sphagnum samples of the plankton (at least for that particular produced some 81 different desmid taxa among moment!). Cyanobacteria follow at some distance which Actinotaenium cucurbita (Ra l f s ) Te i l i n g , in second place (Fig. 2). It is maybe of interest Actinotaenium wollei (W. et G.S.We s t ) Rů ž i č k a to mention that no protozoans or multicellular et Po u z a r , Tetmemorus laevis Ra l f s and animals (crustaceans, etc.) were encountered Haplotaenium minutum (Ra l f s ) Ba n d o were in the (fresh) plankton samples, although the the predominant ones. Somewhat less abundant presence of obscure unicellular plant or animal were Euastrum praemorsum (No r d s t .) Sc h m i d l e , species that belong to other groups than desmids Xanthidium mucronulatum (No r d s t .) Co u t é et or blue–green algae may be overlooked. It seems Te l l , Netrium digitus It z i g s . et Ro t h e , Cosmarium safe to say that at least 95% of the specimens pyramidatum W.Ar c h e r , Bambusina borreri gathered by the plankton net do belong to desmids (Ra l f s ) Cl e v e , Desmidium graciliceps (No r d s t .) and blue–greens. La g e r h e i m and Staurastrum wildemanii Gu t w . A closer look at the composition of the For a number of rather incidentally encountered, desmid fraction learns that it consists of just a but taxonomically and biogeographically more few species, approx. 10, and that they all have a interesting taxa, see taxonomic account below. relatively small cell size (< 50 µm). It is interesting to compare this species number with the one found in the only sample that was taken from the Taxonomic account lake shore. This sample (2007–017) was collected by squeezing out the roots of reed–like grasses Because of huge difficulties to trace and examine that were exposed directly to the lake water. It type specimens of desmid taxa in the original contained approx. 25 species, among which larger sample material, in the taxonomic account below, ones. This difference in desmid diversity between for all synonyms provided, illustrations making the two sampling places shows once more the part of the original description are considered preference of desmids to a more benthic way of the type material (holotype). As, moreover, it is life. almost unfeasonable to preserve a single cell as a The predominant desmid species in the type specimen, according to art. 37.5 of the Vienna net samples was Staurastrum longicolle (see the Code (McNe i l l et al. 2006) in the present paper taxonomic account of the present paper). Other names of new taxa are connected to illustrations abundant species were Staurastrum arcuatum as well. No r d s t ., Staurodesmus omearae (W.Ar c h e r ) Te i l i n g and Staurodesmus dejectus (Ra l f s ) Actinotaenium angulatum (W. et G.S.We s t ) Te i l i n g ; all specimens had cell dimensions close Rů ž i č k a et Po u z a r to the smallest sizes mentioned in literature. St. Folia Geobot. Phytotax. 13: 41 (1978). longicolle was also abundant in the reed sample Basionym: Cylindrocystis angulata W. et G.S.We s t but totally absent in the Sphagnum samples. The Trans. Linn. Soc. London, Bot. 5: 237, pl. 13: 25, 26 other, less abundant, species were very small. A (1896). number of them, mainly representatives of the genera Cosmarium (maybe even Cosmocladium) var. brasiliense (Gr ö n b l a d ) Rů ž i č k a et Po u z a r and Staurastrum were but little characteristic and (Figs 3–4, 13–14) could not be identified. All planktonic species Folia Geobot. Phytotax. 13: 42 (1978). showed thready extrusions radiating from the Basionym: Cosmarium floridanum Lü t k e m . var. cell body. These extrusions are probably part brasiliense Gr ö n b l a d of a gelatinous envelope that surrounds the Acta Soc. Sci. Fenn., Ser. B, Opera Biol. 2 (6): 18, pl. whole body of the cell and helps the cells to stay 6: 108, 109 (1945). suspended in the water column or hinder predation Synonym: Actinotaenium tumidum var. brasiliense by zooplankton (Co e s e l 1994). These envelopes (Gr ö n b l a d ) Te i l i n g were difficult to see under the (light) microscope Bot, Not. 107: 402, fig. 52 (1954). 98 van Ge e s t & Co e s e l : Desmids from Lake Nabugabo

Actinotaenium angulatum is marked by fairly view by the occurrence of four instead of three large cells. Semicells are conical in shape with protuberances in the semicell centre, in lateral about straight sides, a truncate apex and rounded view by a doubled median lobe. Cell length 52–58 apical angles (Fö r s t e r 1982). A. angulatum was μm, cell breadth 34–36 μm, cell thickness 21–24 originally described from North America (We s t μm, breadth of isthmus 8–11 μm. – Type: our & We s t 1896), var. brasiliense from Brazil Fig. 15. Type locality: shore of Lake Nabugabo, (Gr ö n b l a d 1945). According to Fö r s t e r (l.c.) the Uganda (sample 2007–021), A. van Geest, July main difference between the nominate variety and 28, 2007. var. brasiliense would lie in the slenderness of the Euastrum gemmatum as depicted by Ra l f s cells (i.e., L/B ca. 2.3 in var. angulatum versus ca. (1848) and in the European floras byW e s t & We s t 3 in var. brasiliense). However, when considering (1905) and Rů ž i č k a (1981) is characterized by a the original diagnoses, there could also be a transversal series of three protuberances at the base difference in cell wall sculpture. Whereas We s t & of the semicell. Our newly described variety is We s t (l.c.) characterize the cell wall in the nominate marked by an additional, equally sized tumour just variety as scrobiculate–punctate, Gr ö n b l a d (l.c.) above the supraisthmial one. In addition to that, the makes mention, in var. brasiliense, of a subtilely median lateral lobe is doubled so that, all in total, porose wall. If that difference would appear to be each semicell is marked by 18 protuberances (lobes reliable and consistent, we might have to do with and tumours) versus 14 in the nominate variety separate species. (compare our Figs 15 and 16. In respect of that Anyhow, our Nabugabo material is feature it resembles Eu. gemmatum var. ornatum characterized by relatively slender cells (L/B as described by Bo u r r e l l y & Co u t é (1991) from 2.7–3.5) with very fine cell wall pores, so fully in Madagascar which, however, is marked by five accordance with the diagnosis of var. brasiliense. instead of four facial protuberances. It should also Cell wall pores in most part of the cell are more or be compared with Eu. gauthierii (including forma less scattered, but those at the base of the semicell bifidum) as described by Bo u r r e l l y (1957) from are arranged in a supraisthmial whorl (Fig. 3) Mali (formerly French Sudan). This latter species whereas a big, deepened apical pore field may be differs from Eu. gemmatum by its much more observed (Fig. 14). Fö r s t e r (l.c.) does mention pronounced facial protuberances, particularly the supraisthmial ring but not the big apical pore. to be seen in apical view. No doubt, all above– Gr ö n b l a d (1945) does not mention or depict such mentioned taxa are closely affiliated, they just an apical pore either, contrary to Kr i e g e r (1950) differ in the number and markedness of their facial and Bo u r r e l l y & Co u t é (1991). As the central, protuberances. apical pore in question (connected to a pit in the Whereas from Europe only the nominate cell wall) depending on the position of the cell variety of Eu. gemmatum is known, the other, is not always quite obvious, it might have been more exuberantly shaped taxa mentioned above overlooked in a number of cases. have only been recorded from tropical Africa. Up to then, A. angulatum var. brasiliense On the Nabugabo site, Eu. gemmatum var. has only been recorded from South America and quadrituberosum was frequently encountered, Africa. On the Nabugabo site, it was frequently next to the nominate variety, in samples 2007–021 encountered in all the Sphagnum samples. and 2007–022 (both Sphagnum).

Euastrum gemmatum Br é b i s s o n ex Ra l f s Euastrum pseudopectinatum Sc h m i d l e (Fig. British Desmidieae: 214, pl. 35: 25 (1848). 17) var. quadrituberosum Co e s e l et Va n Ge e s t var. Bot. Jahrb. Syst. 26: 46, pl. 2: 39 (1898). nov. (Fig. 15) Euastrum pseudopectinatum differs from Eu. Diagnosis: A varietate typica protuberationibus 4, pectinatum Ra l f s in that its apical lobe is more contra 3 ad centrum semicellularem lateraliter lobo strongly dilate with distinctly recurved apical mediano duplicato differt. Cellularum longitudo 52–58 angles, whereas the outline of the basal part is µm, latitudo 34–36 µm, crassitudo 21–24 µm, isthmi trapeziform rather than rectangular (Kr i e g e r 1937). latitudo 8–11 µm. – Typus: Figura nostra 15. Eu. pseudopectinatum was described by Sc h m i d l e (1898) from the island of Zanzibar. Later on, that Differs from the nominate variety in frontal same author described Eu. pseudopectinatum Fottea 12(1): 95–110, 2012 99 var. evolutum, marked by indented basal and Whereas M. doveri var. africanum is particularly lateral lobes and wanting tubercles at the apical recorded from African countries (Bo u r r e l l y angles, from Lake Nyasa (Sc h m i d l e 1902). We s t 1961; Li n d 1971; Bo u r r e l l y & Co u t é 1991; (1907) represented, under the name of just Eu. Op u t e 1992), M. doveri var. curvata, as well as pseudopectinatum, an algal form comparable with some other closely affiliated varieties are known our one from a swamp in present–day Tanzania. In from tropical Asia, Australia and South America the present investigation Eu. pseudopectinatum, as well. On the Nabugabo site, M. doveri var. apart from Lake Nabugabo, was also found some africanum was frequently encountered in all the 70 km NE from the Nabugabo site ( i.e. Mamamba Sphagnum samples. swamp). When considering the morphological variability as shown by specimens from both sites Micrasterias stuhlmannii Hi e r o n . (Fig. 17 from the Nabugabo site and Fig. 18 from Engler, Pflanz. Ost–Afr. C: 21 (1895). the Mabamba site) there seems to be insufficient var. nabugabonum Co e s e l et Va n Ge e s t var. ground to distinguish a separate var. evolutum nov. (Figs 20–21) indeed. Diagnosis: A varietate typica lobulis lateralibus minus Eu. pseudopectinatum is only known gracilibus et dissimilibus differt. Cellularum longitudo from eastern Africa. On the Nabugabo site, it 172–192 µm, latitudo 132–152 µm, isthmi latitudo 26 was frequently encountered in all the Sphagnum µm. – Typus: Figura nostra 20. samples. Differs from the nominate variety by less slender Micrasterias doveri Bi s w a s and less differentiated lateral lobules. Cell length J. Fed. Malay States Mus. 14 (3/4) : 421, pl. 12: 36 172–192 μm, cell breadth 132–152 μm, breadth of (1929). isthmus 26 μm. – Type: our Fig. 20. Type locality: var. africanum Bo u rr . (Fig. 19) shore of Lake Nabugabo, Uganda (sample 2007– Bull. Inst. Franç. Afr. Noire, Sér. A. 23 (2): 337, 358, 018), A. van Geest, July 28, 2007. pl. 16: 1–3 (1961). Typus: Tabula 16: 3. The most striking feature in the Micrasterias form depicted in our figures, is the outline of the We herewith validate the name of the above– upper part of the apical lobe, i.e., dilated, the mentioned variety because in the above paper dorsal side showing a median depression and indication of a nomenclatural type is wanting recurved, dentate extremities. In respect of that, (Art. 37.1 ICBN). there is some resemblance with given forms of M. Actually, the algal form under discussion is conferta P.Lu n d e l l , M. tetraptera W. et G.S.We s t intermediate between Micrasterias doveri Bi s w a s and M. cunningtonii G.S.We s t which, however, are and M. torreyi var. curvata Wi l l i Kr i e g .. Therefore characterized by a much stronger dilatation of the it is not surprising that it may be encountered in apical lobe. A better fit is found inM. stuhlmannii literature under both names (e.g., Va n Oy e 1953; Hi e r o n . as depicted by Sc h m i d l e (1898). Sc h m i d l e Op u t e 1992). Kr i e g e r (1939) placed M. doveri (l.c.) based his illustrations on material that he as var. doveri under M. torreyi Ba i l e y ex Ra l f s . got from Ad o l f En g l e r and Ge o r g Hi e r o n y m u s . When comparing, however, the original figures of The material in question was collected by Fr a n z M. torreyi (var. torreyi), M. torreyi var. curvata St u h l m a n n and Ge o r g Vo l k e n s from Tanzania. and M. doveri as reproduced in Kr i e g e r (1939), Hi e r o n y m u s (1895) described M. stuhlmannii the similarity between M. torreyi var. curvata and without providing any illustrations but as Sc h m i d l e M. doveri is much more obvious than between M. studied the same material as Hi e r o n y m u s did, it is torreyi var. curvata and M. torreyi var. torreyi. almost certain that Sc h m i d l e ’s pictures refer to the This was also noticed by Th o m a s s o n (1960) and same species. Bo u r r e l l y (1961). Consequently, Th o m a s s o n Our newly described var. nabugabonum (1986) formally transferred var. curvata from M. differs from the nominate variety in that the torreyi to M. doveri. It is questionable however, lateral lobules are less slender. Moreover, whereas taking M. doveri as a separate species, whether differentiation of the lateral lobules in var. M. doveri var. curvata deserves the status of a nabugabonum is not further than to the third order, separate variety next to M. doveri var. africanum. the picture of the nominate variety in Sc h m i d l e Mutual differences are so small that it is often (1898, pl. 3: 15) shows also some lobules of hard to make a choice. the fourth order. Bo u r r e l l y (1961) classed M. 100 van Ge e s t & Co e s e l : Desmids from Lake Nabugabo

Figs 2–6. (2) Net plankton of Lake Nabugabo predominated by the desmid Staurastrum longicolle and some blue–greens (presumably Microcystis sp. and Planktolyngbia sp.); (3–6) SEM photographs: (3–4) Actinotaenium angulatum var. brasiliense; (5) Staurastrum trihedrale in apical view; (6) Staurastrum longicolle with reduced terminal spines and instead of that many terminal mucilage extrusions. Scale bar 100 μm (for 2), 10 μm (for 3–6). Fottea 12(1): 95–110, 2012 101

Figs 7–12. Light photographs of Staurastrum longicolle from benthic (left hand series) and limnetic (right hand series) environment. Scale bar 10 μm. 102 van Ge e s t & Co e s e l : Desmids from Lake Nabugabo

Figs 13–27. (13–14) Actinotaenium angulatum var. brasiliense; (15) Euastrum gemmatum var. quadrituberosum; (16) E. gemmatum var. gemmatum; (17–18) E. pseudopectinatum; (19) Micrasterias doveri var. africanum; (20–21) M. stuhlmannii var. nabugabonum; (22–24) Cosmarium maximum var. latum; (25–27) C. nabugabonum. Scale bar 30 μm (for 13–18, 25–27), 60 μm (for 19–24).

stuhlmannii as a variety of M. apiculata Ra l f s (both Sphagnum). but in our opinion M. stuhlmannii does represent a species of its own. As far as could be traced, M Cosmarium maximum (Bö r g e s e n ) W. et stuhlmannii is only known from Africa (Sc h m i d l e G.S.We s t 1898; Bo u r r e l l y 1961; Li n d 1971, Bo u r r e l l y J. Bot. 35: 114 (1897). & Co u t é 1991). On the Nabugabo site, M. var. latum A.M.Sc o t t (Figs 22–24) stuhlmannii var. nabugabonum was infrequently Acta Bot. Fenn. 66: 20, pl.10: 224–226 (1964). Typus: encountered in samples 2007–018 and 2007–020 Tabula 10: 225. Fottea 12(1): 95–110, 2012 103

We herewith validate the name of the above– smooth. Semicells in apical view rhomboid with mentioned variety because in the above paper broadly rounded angles. Cell wall thickened at the indication of a nomenclatural type is wanting angles. Cell length 17–18 μm, cell breadth 11–12 (Art. 37.1 ICBN). μm, cell thickness 9–10 μm, breadth of isthmus 5 Cosmarium maximum was originally μm. – Type: our Fig. 27. Type locality: shore of described by Bø r g e s e n (1890) from Brazil as a Lake Nabugabo, Uganda (sample 2007–022), A. variety of C. obsoletum (Ha n t z s c h ) Re i n s c h . To van Geest, July 28, 2007. our mind, We s t & We s t (1897) justly raised it At first glance, the above newly described to species level, not only owing to larger cell species resembles Cosmarium helcangulare var. dimensions, but mainly because of a much brasiliense Wi l l i Kr i e g ., exclusively known deeper constriction of the cell (as compared from a site in southeastern Brazil (Kr i e g e r with C. obsoletum). Sc o t t , in Gr ö n b l a d et al. 1950). Semicells in both taxa are in frontal view (1964) described C. maximum var. latum from cuneate in outline with a slightly concave apex. Uganda, differing from the nominate variety However, whereas semicells in C. helcangulare by a somewhat higher cell breadth/length ratio var. brasiliense in apical view are about elliptic resulting into an almost circular cell outline. As is in outline, those in C. nabugabonum are thick– shown in our Fig. 24, the characteristic papillate set rhomboid. Anyhow, in our opinion, C. projections on the basal angles sometimes are nabugabonum is not affiliated to C. helcangulare wanting. In that case, C. maximum var. latum may as originally described by No r d s t e d t (1888b) be confused not only with C. obsoletum, but also from the Danish island of Bornholm. Interestingly, with C. lundellii De l p o n t e , C. dorsitruncatum both C. nabugabonum and C. helcangulare var. (No r d s t .) G.S.We s t , C. dorsitruncatiforme brasiliense were collected from Sphagnum pools. Gu t w ., C. circulare Re i n s c h , C. baileyi Wo l l e On the Nabugabo site, C. nabugabonum was and, presumably, even more species. frequently encountered in samples 2007–020 and C. maximum var. latum has only been 2007–022 (both Sphagnum). recorded from Africa, i.e., Madagascar (Bo u r r e l l y & Le b o i m e 1946, as C. maximum) Xanthidium thomassonii Co e s e l et Va n Ge e s t and Uganda (Gr ö n b l a d et al. 1964; Li n d sp. nov. (Fig. 28–29) 1971, as Staurodesmus croasdaleae var. latus (A.M.Sc o t t ) Te i l i n g ) but in view of the high Diagnosis: Cellulae spinis exclusis frontaliter longiores chance of confusion with other species a wider quam latae profunde constrictae sinu aperto angulo geographical distribution is not to be precluded. acuto. Semicellulae circa hexagonae spinis duabus On the Nabugabo site, C. maximum var. latum in quoque angulo apicali plerumque spina una in was encountered frequently in all the Sphagnum quoque angulo laterali et protuberatione papilliformi samples. in quoque angulo basali. Cellulae paries aliter laevis. Semicellulae apicaliter visae late ellipticae polis Cosmarium nabugabonum Co e s e l et Va n Ge e s t acuminatis in spinas longas terminantes, corpus sp. nov. (Figs 25–27) spinis quatuor intramarginalibus crucialiter ordinatis ornatus. Cellulae praeter spinos 43–47 μm longae, 40– Diagnosis: Cellulae circa duplo longiores quam latae 43 μm latae. Isthmi latitudo 10–12 µm. Spinae usque aliquantum profunde constrictae. Sinus V–formis. ad 19 μm longae. – Typus: Figura nostra 28. Semicellulae ambitu plusminusve cuneatae, apicibus et lateribus lateribus leviter concavis, angulis late Cells exclusive of spines in frontal view longer rotundatis. Cellulae paries laevis. Semicellulae than broad, deeply constricted with an open, apicaliter visae rhomboideae, angulis late rotundatis acute–angled sinus. Semicells about hexagonal incrassatis. Cellularum longitudo 17–18 µm, latitudo with two spines at each apical angle, generally 11–12 µm, crassitudo 9–10 µm, isthmi latitudo 5 µm. – one spine at each lateral angle and a papilla–like Typus: Figura nostra 27. protrusion at each basal angle. Cell wall otherwise smooth. Semicells in apical view broadly elliptic, Cells about twice as long as broad, rather deeply the acuminate poles ending in a long spine; the constricted. Sinus V–shaped. Semicells in rough body with four, cruciately arranged intramarginal outline cuneate with broadly rounded angles and spines. Cell length without spines 43–47 μm, slightly concave apices and lateral sides. Cell wall cell breadth without spines 40–43 μm, breadth of 104 van Ge e s t & Co e s e l : Desmids from Lake Nabugabo

Figs 28–38. (28–29) Xanthidium thomassonii; (30–31) Staurodesmus eckertii var. africanus; (32) Staurastrum capitulum var. foersteri; (33–34) S. corbula var. pulchrum; (35–36) Staurastrum longicolle; (37) S. trihedrale; (38) Spondylosium rectangulare. Scale bar 30 μm (for 28–37), 60 μm (for 38).

isthmus 10–12 μm. Maximum length of spines 19 by Th o m a s s o n (1960, pl. 10: 18) under the name μm – Type: our Fig. 28. Type locality: shore of of Xanthidium antilopaeum var. pseudotropicum Lake Nabugabo, Uganda (sample 2007–018), A. Gr ö n b l a d . However, that variety, described by van Geest, July 28, 2007. Gr ö n b l a d (1945) from Brazil, in the outline of The above newly described species was depicted its semicells is essentially different from our alga Fottea 12(1): 95–110, 2012 105 under consideration. Although of Xanthidium parallel (versus divergent) spines. However, since antilopaeum tens of different varieties and formae then, of both species a number of varieties have have been described, none of those meets the been described that are more or less intermediate illustration in Th o m a s s o n (l.c.). In our opinion, in morphology. Compare, e.g., Std. eckertii var. many of those X. antilopaeum varieties and formae convexus forma divergens described by Th é r é z i e n represent species of their own. Also in case of our (1985) from French Guyana and Std. calyxoides taxon under discussion we prefer to render it the forma major described by Bo u r r e l l y & Co u t é status of species rather than that of a variety. Like (1991) from Madagascar. Considering the original in many Xanthidium species the number of spines diagnoses, the algal form represented in our Figs is not very fixed, the single spine at the lateral 30–31 better fitsStd. eckertii than Std. calyxoides, angles occasionally may be doubled (Fig. 29). so is described as a variety of the former species. So far, X. thomassonii could only be traced Std. eckertii was not recorded from Africa from Zambia (Th o m a s s o n l.c.). On the Nabugabo before whereas the somewhat resembling Std. site, it was infrequently encountered in all the calyxoides var. major described by Bo u r r e l l y Sphagnum samples. & Co u t é (l.c) is the only African record of Std. calyxoides. So, obviously, the main point of Staurodesmus eckertii (Ku r t Fö r s t .) Te i l i n g distribution of both species is on the American Ark. Bot. 6 (11): 493 (1967). continents. On the Nabugabo site, Std. eckertii Basionym: Staurastrum eckertii Ku r t Fö r s t . var. africanus was only incidentally encountered Hydrobiologia 23: 419, pl. 34: 3, 4, pl. 49: 1 (1964). in sample 2007–021 (Sphagnum). Typus: Tabula 34: 1. Staurastrum capitulum Br é b i s s o n ex Ra l f s We herewith validate the name of Staurastrum British Desmidieae: 214, pl. 35: 25 (1848). eckertii Ku r t Fö r s t . as in the above paper var. foersteri Co e s e l et Va n Ge e s t var. nov. indication of a nomenclatural type is wanting (Fig. 32) (Art. 37.1 ICBN). The name of Staurodesmus eckertii (Ku r t Fö r s t .) Te i l i n g is validated by Diagnosis: Differt a varietate typica cellulis 4–radiatis providing a full and direct reference to Fö r s t e r ’s angulis apicalibus in processus brevissimos plusminusve original publication (Art. 33.2 ICBN). truncatos productis. Cellularum longitudo 32–41 µm, latitudo 20–29 µm, isthmi latitudo 12–13 µm. – Typus: var. africanus Co e s e l et Va n Ge e s t var. nov. Figura nostra 32. (Figs 30–31) Differs from the nominate variety by 4–radiate Diagnosis: A varietate typica semicellulis ellipsoideis cells whose apical angles are produced into very spinis (plusminusve) convergentibus differt. Cellulae short, more or less truncate processes. Cell length praeter spinos 37–42 μm longae, 30–38 μm latae. 32–41 µm, cell breadth 20–29 µm, breadth of Cellularum crassitudo 27–28 µm. Spinae usque ad 18 isthmus 12–13 μm. – Type: our Fig. 32. Type μm longae. – Typus: Figura nostra 30. locality: shore of Lake Nabugabo (sample 2007– 022), A. van Geest, July 28, 2007. Differs from the nominate variety by ellipsoid The algal form represented in our Fig. 32 semicells and (slightly) convergent spines. Cell agrees with those depicted by Fö r s t e r (1963, length without spines 37–42 μm, cell breadth 1964) from Brazil under the name of Staurastrum without spines 30–38 μm, cell thickness 27–28 capitulum var. tumidiusculum (No r d s t .) W. μm. Maximum length of spines 18 μm. – Type: our et G.S.We s t . However, var. tumidiusculum as Fig. 30. Type locality: shore of Lake Nabugabo, originally described by No r d s t e d t (1888a) from Uganda (sample 2007–021), A. van Geest, July New Zealand is characterized by acuminate apical 28, 2007. angles, whereas the apical angles in var. foersteri The pluriradiate species Staurodesmus are produced into (very) short, more or less eckertii, as originally described by Fö r s t e r (1964) truncate processes. In respect of that latter feature from Brazil differs from the roughly similar there is much resemblance with given forms of Std. calyxoides (Wo l l e ) Cr o a s d a l e , primarily Staurastrum donnellii Wo l l e , in particular S. known from North America, by a higher degree donnellii var. ornatum described by Bo u r r e l l y & of radiation, a wider opened sinus and about Le b o i m e (1946) from Madagascar. 106 van Ge e s t & Co e s e l : Desmids from Lake Nabugabo

S. capitulum var. foersteri is especially known from both taxa, but the shape of the semicell body South America but, maybe, is also in Africa more is distinctly different. Moreover, whereas S. widely distributed. The picture of S. capitulum var. unicorne is known from several countries in the acanthophorum No r d s t . recorded by Bo u r r e l l y Indomalaysian/Northern Australian region (e.g., & Co u t é (1991) from Madagascar obviously Tu r n e r 1892; We s t & We s t 1902; Sc o t t & does not refer to var. acanthophorum but to our Pr e s c o t t 1958), S. longicolle is exclusively known newly described taxon. On the Nabugabo site, S. from tropical Africa. Remarkably, Te i l i n g (1967) capitulum var. foersteri was only occasionally in his monography on the genus Staurodesmus encountered in sample 2007–22 (Sphagnum). listed S. unicorne var. longicolle as Staurodesmus unicornis var. gracilis forma longicollis but it is Staurastrum corbula W. et G.S.We s t quite obvious that our taxon under discussion with J. Bot. 35: 179, pl. 369: 2 (1897). its long, arm–like processes has to be considered var. pulchrum W. et G.S.We s t (Figs 33–34) a Staurastrum, not a Staurodesmus species. As is J. Bot. 35: 179, pl. 369: 3 (1897). shown in our Figs 6–12, the marked spine at the end of the arm–like processes may be reduced to such The algal form represented in our figures very well a degree that it is almost wanting. Whereas those agrees with Staurastrum corbula var. pulchrum as spines were found to be well developed in cells described by We s t & We s t (1897) from Angola. collected from perifyton on the roots of reed (Figs The variety in question differs from the nominate 7, 9, 11), they were highly reduced in the majority variety by a concave apex and lateral sides that are of cells collected from plankton. Strikingly, those indented in the mediane part. No doubt, S. corbula latter cells at the end of the processes produced is closely affiliated if not identic to S. welwitschii gelatinous, bar–like extrusions which, at first described by We s t & We s t (l.c.) in that same paper. glance, are easily to be interpreted as spines (Figs Both S. corbula and S. welwitschii are only known 8, 10, 12). from Africa and obviously pretty rare. Apart from Up to then, S. longicolle was only known S. welwitschii recorded by Bo u r r e l l y & Le b o i m e from Sudan (Gr ö n b l a d et al. 1958), Zambia (1946) from Madagascar and S. corbula var. (Th o m a s s o n 1960) and Madagascar (Bo u r r e l l y & simplex described by Bo u r r e l y & Co u t é (1991), Co u t é 1991). On the Nabugabo site, S. longicolle also from Madagascar, no other finds could be was the dominant desmid species in the plankton traced. On the Nabugabo site, S. corbula var. samples but was also frequently encountered in pulchrum was frequently encountered in the sample 2007–017 (submerged roots of reed). Sphagnum samples. Staurastrum trihedrale Wo l l e (Figs 5, 37) Staurastrum longicolle (Gr ö n b l a d et Bull. Torr. Bot. Club 10: 20, pl. 27: 20 (1883). A.M.Sc o t t ) Co e s e l et Va n Ge e s t stat. nov. (Figs 6–12, 35–36) Although simple in shape and lacking a distinct Basionym: Staurastrum unicorne var. longicolle cell wall ornamentation, Staurastrum trihedrale Gr ö n b l a d et A.M.Sc o t t is readily to be identified. Wo l l e (1883), when Acta Bot. Fennica 58: 43, pl. 20: 295–298, pl. 29: 404 describing this species from Massachusetts, (1958). characterized the cells as being ‘punctate, Typus: Tabula 20: 298. granulate’. This circumscription suggests a scrobiculate cell wall, rather than a truly granulate We herewith validate the name of the above– one. As a matter of fact, Wo l l e (l.c.) did not picture mentioned variety because in the above paper any cell wall granules, neither is this the case in indication of a nomenclatural type is wanting any later publication dealing with this species. On (Art. 37.1 ICBN). the other hand, as is shown in a SEM picture of Staurastrum longicolle is a characteristic our material (Fig. 5) the cell wall is most coarsely species, hardly to be confused with any other scrobiculate. In addition to that, our pictures show desmid species. Originally, it was described as a characteristic apical depression, a feature that a variety of S. unicorne W.B.Tu r n e r (Gr ö n b l a d may also be noticed in pictures by Fö r s t e r (1963) et al. 1958). It is true, the shape of the swollen and Wi l l i a m s o n (1994). Of S. trihedrale various ends of the processes furnished with a prominent, varieties have been described which seem to single, obliquely disposed spine is similar in represent but taxonomically insignificant forms. Fottea 12(1): 95–110, 2012 107

S. trihedrale is particularly known from the Consequently, in limnetic habitats only desmid American continents (e.g., Pr e s c o t t et al. 1982) species with a high cell surface area/volume ratio, but it has also been recorded from Asia (Hi r a n o so a high form resistance, are to be expected. 1953; Hi n o d e 1960), New Zealand (Sk u j a 1976) Generally speaking, those will have relatively and Africa. As for the latter continent most finds small cell dimensions and/or relatively long are from South Africa (Fr i t s c h 1914; Cl a a s s e n processes. 1961; Wi l l i a m s o n 1994) but there is also a Despite the ability of a number of desmid record from Madagascar (Bo u r r e l l y & Le b o i m e species to flourish in a limnetic habitat, in 1946). On the Nabugabo site, S. trihedrale was temperate climatic regions these algae but seldom infrequently encountered in samples 2007–018, quantitatively dominate the phytoplankton 2007–020 and 2007–021 (all Sphagnum). assembly, even when oligotrophic softwater lakes are considered (Br o o k 1981). It has been Spondylosium rectangulare (Wo l l e ) W. et recognized, however, that the quantitative G.S.We s t (Fig. 38) importance of planktonic desmids in tropical lakes Trans. Linn. Soc. London, Bot. 5: 231, pl. 12: 13, 14 is higher than in temperate ones (e.g., Bi s w a s 1929; (1896). Hu z a r & Re y n o l d s 1997). A possible explanation for this may be found in the phenomenon of Spondylosium rectangulare is a large–sized, atelomixis: diurnal mixing of the water column characteristically shaped taxon that can hardly be resulting from high differences in air temperature confused with any other Spondylosium species. It between day and night. By these turbulences the is widely distributed on the American continents risk of sinking of desmid cells is substantially (e.g., Cr o a s d a l e et al. 1983) but, as far as could diminished (Ba r b o s a & Pa d i s a k 2002). be traced, from Africa but a single record was The quantitative predominance of known, i.e. from Lake Shiwa Ngandu in Zambia desmids as encountered in the plankton of Lake (Th o m a s s o n 1966). On the Nabugabo site, only Nabugabo fits this experience. Interestingly, the one filament of Spondylosium rectangulare was most dominant desmid species in the plankton, encountered in sample 2007–20 (Sphagnum). i.e. Staurastrum longicolle, showed a consistent reduction of the large spine at the end of the cell processes characteristic of this species, Discussion whereas that spine was well developed in the benthic specimens of S. longicolle collected in As compared with the number of species found the nearby reed zone. This might be viewed in in the reed and the bog samples (some 81 in the the light of speciation of originally benthic life Sphagnum samples and 25 in the reed sample) forms in a limnetic environment. We s t & We s t the number of species encountered in the open (1909) suggest that the process of morphological water of Lake Nabugabo (about 10) is low. As adaptation to pelagic conditions is a gradual mentioned earlier, exclusively planktonic desmid one, occupying a long period of evolution, species are relatively rare. We s t & We s t (1909) Br o o k (1959), on the contrary, is of opinion that on a total of 236 desmid species encountered in the plasticity of the desmid cell allows a rapid British softwater lakes classify only 14 of them as adaptation to the planktonic habitat taking place being exclusively confined to the plankton. annually. These two theories need not be per se Co e s e l & Me e s t e r s (2007) provide a list contrary but could be complementary. What starts of 831 desmid taxa found in the Netherlands, as a phenotypic variation may get a genetical 511 of which are classified for a given life form. base in the course of a longer time period. To get Only 20 of these 511 taxa (4%) are marked as more insight in the nature of the morphological euplanktonic, most of them being characteristic differences within S. longicolle as noticed above, of eutrophic waters. Also in the list of desmid a much more extensive investigation covering species recently provided for the Czech Republic the large marshes on the southern border of Lake (Šť a s t n ý 2010) only 18 out of 526 taxa are Nabugabo and some of the adjacent smaller lakes marked as exclusively planktonic. The low per- is needed. centage of planktonic desmid species may be When considering the desmid species explained from the overall large cell dimensions composition of the Sphagnum samples one of in this group of algae causing high sinking rates. the most striking findings is that the predominant 108 van Ge e s t & Co e s e l : Desmids from Lake Nabugabo

species, viz. Actinotaenium cucurbita, In: Cr a m e r , J. (ed.): Bibliotheca Phycologica Haplotaenium minutum and Tetmemorus laevis, 86. – 349 pp., Gebrüder Borntraeger belong to the most common species in Sphagnum Verlagsbuchhandlung, Berlin/Stuttgart. Bo u r r e l l y , P. & Le b o i m e , R. (1946): Notes sur peatland in temperate regions too (e.g., Co e s e l 1975). Possibly this may be related to the quelques algues d’eau douce de Madagascar. – Biol. Jaarb. 13: 75–111. low trophic state and low pH characteristic of Br o o k , A.J. (1959): The status of desmids in the Sphagnum vegetation creating rather extreme plankton and the determination of phytoplankton environmental conditions which are optimal to but quotients. – J. Ecol. 47: 429–445. a relative low number of species. A more extreme Br o o k , A.J. (1981): The Biology of Desmids. – In: example of this phenomenon is the occurrence Bu r n e t t , J.H. (ed.): Botanical Monographs of a characteristic alpine desmid flora which is 16. – 276 pp., University of California Press, not confined to the European mountains but also Berkeley/Los Angeles.. known from high mountains in tropical Africa, Ch a p m a n , L.J.; Ba l i r w a , J.; Bu g e n y i , F.W.B.; Ch a p m a n , C. & Cr i s m a n , T.L. (2001): Wetlands of East South America and Asia (Co e s e l 1996). Africa: Biodiversity, exploitations, and policy Next to the above–mentioned, predominant perspectives. – In: Go p a l , B.; Ju n k , W.J. & species we did find (in lower quantities) a series Da v i s , J.A. (eds): Biodiversity in Wetlands: of other desmid taxa in the Sphagnum samples, Assessment, Function, and Conservation, Vol. among which quite a number that may be 2. – pp. 101–132, Backhuys Publisher, Leiden. considered African endemics. Yet, with a total of Ch e n g , D.N.K. (2006): Weather information for about 80 taxa our output is distinctly lower than . – World Meteorological Organization that mentioned by Li n d (1971) who recorded 180 (http://www.worldweather.org). Cited March taxa. According to the description of her sampling 12, 2011. sites, those were former sand pits vegetated by Cl a a s s e n , M.I. (1961): A contribution to our knowledge plant species such as Nymphaea, Phragmites, of the freshwater algae of the Transvaal Province. – Bothalia 7: 559–666. Cyperus, Typha and Utricularia indicating more Co e s e l , P.F.M. (1975): The relevance of desmids in mesotrophic conditions which form the optimal the biological typology and evaluation of fresh habitat to desmids (Co e s e l & Me e s t e r s 2007). waters. – Hydrobiol. Bull. 9: 93–101. Co e s e l , P.F.M. (1994): On the ecological significance of a cellular mucilaginous envelope in planktic Acknowledgements desmids. – Algological Studies 73: 65–74. We are much obliged to Dr A. Veen and Dr F.A.C. Co e s e l , P.F.M. (1996): Biogeography of desmids. – Kouwets (Waterdienst, Lelystad) for offering SEM Hydrobiologia 336: 41–53. facilities and to Dr J.F. Veldkamp (Nationaal Herbarium Co e s e l , P.F.M. & Me e s t e r s , J. (2007): Desmids of the Nederland, Leiden branch) for Latin translation of the Lowlands. Mesotaeniaceae and diagnoses. A.M.T. Joosten is acknowledged for help of the European Lowlands. – 351 pp., KNNV with the identification of some cyanophyte genera. Publishing, Zeist, The Netherlands. Cr o a s d a l e , H.; Bi c u d o , C.E.M. & Pr e s c o t t , G.W. (1983): A Synopsis of North American desmids, References Part 2, Section 5. – 117 pp., University of Nebraska Press, Lincoln/London. Ba r b o s a , F.A.R. & Pa d i s a k , J. (2002): The forgotten Ef i t r e , J.; Ch a p m a n , L.J. & Ma k a n g a , B. (2001): lake stratification pattern: atelomixis, and its The inshore benthic macroinvertebrates of ecological importance. – Int.Vereinigung Theor. Lake Nabugabo, Uganda: seasonal and spatial Limnol. Verh. 28: 1385–1395. patterns. – African Zoology 36: 205–216. Bi s w a s , K.P. (1929): Papers on Malayan aquatic Fö r s t e r , K. (1963): Desmidiaceen aus Brasilien. 1. – biology IV. Freshwater algae. – J. Fed. Malay Rev. Algol. 7: 38–92. States Mus. 14: 404–435, 479–481. Fö r s t e r , K. (1964): Desmidiaceen aus Brasilien. 2. – Bo u r r e l l y , P. (1957): Algues d’eau douce du Soudan Hydrobiologia 23: 321–505. Français, région du Macina (A. O. F.). – Bull. Fö r s t e r , K. (1982): Conjugatophyceae: Zygnematales Inst. Franç. Afr. Noire, Sér. A, 19: 1047–1102. und (excl. Zygnemataceae). – In: Bo u r r e l l y , P. (1961): Algues d’eau douce de la Hu b e r –Pe s t a l o z z i , G. (ed.): Das Phytoplankton République de Cote d’Ivoire. – Bull. Inst. Franç. des Süsswassers, 8. Teil, 1. Hälfte. – 543 pp., Afr. Noire, Sér. A, 23: 283–398. E. Schweizerbart’sche Verlagsbuchhandlung, Bo u r r e l l y , P. & Co u t é , A. (1991): Desmidiées de Stuttgart. Madagascar (Chlorophyta, Zygophyceae). – Fr i t s c h , F.E. (1914): Contributions to our knowledge Fottea 12(1): 95–110, 2012 109

of the freshwater algae of Africa. I. – Ann. Biol. Dr S. Berggren in New Zealand and Australia. Lacustre 7: 40–59. – Kongl. Svenska Vetenskapsakad. Handl. 22: Gr ö n b l a d , R. (1945): De algis Brasiliensibus, praecipue 1–98. Desmidiaceis, in regione inferiore fluminis No r d s t e d t , O. (1888b): Desmidieer från Bornholm. – Amazonas a Professore August Ginzberger Vidensk. Meddel. Naturh. Forening Kjøbenhavn (Wien) anno 1927 collectis. – Acta Soc. Sci. 1888: 188–213. Fenn., Ser. B, Opera Biol. 2: 1–43. Op u t e , F.I. (1992): Contribution to the knowledge of Gr ö n b l a d , R.; Pr o w s e , G.A. & Sc o t t , A.M. (1958): algae of Nigeria. I. Desmids from the Warri/ Sudanese desmids. – Acta Bot. Fennica 58: Forcados Estuaries. II. The genera Euastrum 1–82. and Micrasterias. – Algological Studies 65: Gr ö n b l a d , R.; Sc o t t , A.M. & Cr o a s d a l e , H. (1964): 73–92. Desmids from Uganda and Lake Victoria. – Pr e s c o t t , G.W.; Bi c u d o , C.E.M. & Vi n y a r d , W.C. Acta Bot. Fenn. 66: 1–57. (1982): A Synopsis of North American desmids, Hi e r o n y m u s , G. (1895): Klasse Conjugatae. – In: Part 2, Section 4. – 700 pp., University of En g l e r , A. (ed.): Die Pflanzenwelt Ost–Afrikas Nebraska Press, Lincoln/London. und der Nachbargebiete. – pp. 19–21, D. Ra m s a r (2003): Lake Nabugabo wetland system. – Reimer, Berlin. Information sheet on Ramsar Wetlands (RIS). Hi n o d e , T., (1960): On some Japanese desmids 2. – The Ramsar Convention on Wetlands (http:// Hikobia 2: 61–64. www.ramsar.org). Cited March 12, 2011. Hi r a n o , M. (1953): The alpine desmids from the Rů ž i č k a , J. (1981): Die Desmidiaceen Mitteleuropas, Japanese Alps. 2. – Bot. Mag. (Tokyo) 66: 205– Band 1, 2. Lieferung. – pp. 293–736, E. 210. Schweizerbart‘sche Verlagsbuchhandlung, Hu s z a r , V.L.M. & Re y n o l d s , C.S. (1997): Stuttgart. Phytoplankton periodicity and sequences Rů ž i č k a , J. & Po u z a r , Z. (1978): Erwägungen über of dominance in an Amazonian flood–plain die Taxonomie und Nomenklatur der Gattung lake (Lago Batata, Pará, Brazil): responses to Actinotaenium Teil. – Folia Geobot. Phytotax. gradual environmental change. – Hydrobiologia 13: 33–66. 346: 169–181. Sc h m i d l e , W. (1898): Die von Professor Dr. Volkens Kl i n g , H.J.; Al m o n d , J.; Mu g i d d e , R. & He ck y , R.E.. und Dr. Stuhlmann in Ost–Afrika gesammelten (2006): Phytoplankton of satellite lakes of Desmidiaceen. – Bot. Jahrb. Syst. 26: 1–59. Lake Victoria Basin Uganda, Africa. Poster Sc h m i d l e , W. (1902): Algen, insbesondere solche Presentation. – Great Lakes of the World des Plankton, aus dem Nyassa–See und seiner Symposium (GLOW IV), Dar Es Salam, Umgebung, gesammelt von Dr. Fülleborn. – Tanzania. Bot. Jahrb. Syst. 32: 55–88. Kr i e g e r , W. (1937): Die Desmidiaceen Europas mit Sc o t t , A.M. & Pr e s c o t t , G.W. (1958): Some freshwater Berücksichtigung der aussereuropäischen algae from Arnhem Land in the Northern Arten. – In: Ra b e n h o r s t ’s Kryptogamenflora Territory of Australia. – Rec. American– von Deutschland, Österreich und der Schweiz Australian Sci. Exped. Arnhem Land 3: 8–136. 13, Abt. 1, Teil 1. – 712 pp., Akademische Sk u j a , H. (1976) Zur Kenntnis der Algen Verlagsgesellschaft, Leipzig. Neuseeländischer Torfmoore. – Nova Acta Kr i e g e r , W. (1939): Die Desmidiaceen Europas mit Regiae Soc. Sci. Upsal., Ser. V: C, 2: 1–159. Berücksichtigung der aussereuropäischen Šť a s t n ý , J. (2010) Desmids (Conjugatophyceae, Arten. – In: Ra b e n h o r s t ’s Kryptogamenflora Viridiplantae) from the Czech Republic; new von Deutschland, Österreich und der Schweiz and rare taxa, distribution, ecology. – Fottea 10: 13, Abt. 1, Teil 2. – 117 pp., Akademische 1–74. Verlagsgesellschaft, Leipzig. Te i l i n g , E. (1967): The desmid genus Staurodesmus. – Kr i e g e r , W. (1950): Desmidiaceen aus der montanen Ark. Bot. 6: 467–629. Region Südost–Brasiliens. – Ber. Deutsch. Bot. Th é r é z i e n , Y. (1985): Contribution à l’étude des Ges. 72: 35–42. algues d’eau douce de la Guyane Française, Li n d , E. (1971): Some desmids from Uganda. – Nova å l’exclusion des diatomées. – In: Cr a m e r , J. Hedwigia 22: 535–585. (ed.): Bibliotheca Phycologica 72. – 275 pp., McNe i l l , J. et al. (2006): International Code of Gebrüder Borntraeger Verlagsbuchhandlung, Botanical Nomenclature (Vienna Code) adopted Berlin/Stuttgart. by the Seventeenth International Congress Th o m a s s o n , K. (1960): Notes on the plankton of Lake Vienna, Austria, July 2005. Regnum veg. 146, Bangweulu. 2. – Nova Acta Regiae Soc. Sci. – 568 pp., A.R.G. Gantner Verlag, Ruggel/ Upsal., Ser. 4, 17: 1–43. Liechtenstein. Th o m a s s o n , K. (1966): Phytoplankton of Lake Shiwa No r d s t e d t , O. (1888a): Freshwater algae collected by Ngandu. – Expl. hydrobiol. Bangweolo– 110 van Ge e s t & Co e s e l : Desmids from Lake Nabugabo

Luapula 4: 1–91. We s t , W. & We s t , G.S. (1902): A contribution to the Th o m a s s o n , K. (1986): Algal vegetation in North freshwater algae of Ceylon. – Trans. Linn. Soc. Australian billabongs. – Nova Hedwigia 42: London, Bot. 6: 123–215. 301–378. We s t , W. & We s t , G.S. (1905): A Monograph of the Tu r n e r , W.B. (1892): Algae aquae dulcis Indiae British Desmidiaceae. Vol. 2. – 206 pp., The orientalis. – Kongl. Svensk. Vetensk. –Akad. Ray Society, London. Handl. 25: 1–187. We s t , W. & We s t , G.S. (1909): The British freshwater Va n Br e e m e n , N. (1995): How Sphagnum bogs down phytoplankton with special reference to the other . – Tree 10: 270–275. desmid plankton and the distribution of British Va n Oy e , P. (1953): Contribution à la connaissance des desmids. – Proc. Roy. Soc. London, Ser. B, Desmidiées du Congo belge. – Hydrobiologia Biol. Sci. 81: 165–206. 5: 239–308. Wi l l i a m s o n , D.B. (1994): A contribution to the We s t , G.S. (1907): Report of the freshwater algae, knowledge of the desmid flora of South Africa including phytoplankton, of the Third and the adjoining states of Ciskei and Swaziland. Tanganyika Expdition conducted by Dr. W.A. – Arch. Hydrobiol./Suppl. 99: 415–487. Cunnington, 1904–1905. – J. Linn. Soc. Bot. Wo l l e , F. (1883): Freshwater algae. VII. – Bull. Torr. 38: 81–197. Bot. Club 10: 13–21. We s t , W. & We s t , G.S. (1896): On some North American Desmidieae. – Trans Linn. Soc. London, Bot. 5: 229–274. We s t , W. & We s t , G.S. (1897): Welwitsch’s African freshwater algae. XI. Desmidiaceae. – J. Bot. © Czech Phycological Society (2012) 35: 77–89, 113–122, 172–183, 235. Received May 15, 2011 Accepted July 18, 2011