taxonID	type	description	language	source
03ABFF6FFF9AB369FF4CFB528A7C6FD1.taxon	description	Cells in frontal view cylindric with a very slight median constriction and broadly rounded apices. Cells in apical view circular. Cell wall smooth. Chloroplast lobostelloid. Each semicell with seven or eight cell wall pores: one in the centre of the apex and six or seven arranged in a ring about half-way the length of the semicell. Zygospores globose, furnished with simple, rather long spines. Dimensions: cell length 8.8 – 9.5 µm, cell breadth 4.8 – 6.6 µm. Diameter of zygospores exclusive of spines 9.0 – 10.7 µm, including spines 14.3 – 18.1 µm.	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9AB369FF4CFB528A7C6FD1.taxon	materials_examined	Type: — THE NETHERLANDS. Drenthe: pool ‘ Baggelhuizen’ near Assen, 53.106 ° N, 6.648 ° E, among submerged mosses on sandy soil of the bank, pH 7.2, conductivity 50 µS cm - 1, Van Westen, 25 May 2010 (holotype L! Hugo de Vries Lab 2013.01, preserved as a fixed natural sample).	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9AB369FF4CFB528A7C6FD1.taxon	diagnosis	Differential diagnosis: — Vegetative cells of A. spinosporum (Figs. 11, 13, 14, 17, 18) may be confused with those of some other, small-sized Actinotaenium species, in particular A. subsparsepunctatum (Grönblad 1921: 38) Coesel (2002: 76) and A. subtile (W. et G. S. West 1897: 479) Teiling (1954: 410) which have a comparable cell shape and chloroplast. However, A. subsparsepunctatum in the original description (Grönblad 1921, as Cosmarium subtile var. subsparsepunctatum) has a cell size that is about twice as large and a cell wall with evenly scattered pores, whereas the zygospores are supplied with short, bifurcate, blunt spines (Coesel 2002). Actinotaenium subtile, in the original description by West & West (1897, as Penium subtile) adopted in their British desmid flora (West & West 1904), is characterized by cells with a subtruncate apex and evenly scattered cell wall pores. Moreover, cell dimensions are also about twice as large as those in our A. spinosporum. As its name indicates, one of the main characteristics of A. spinosporum is the spiny zygospore (Figs. 12, 15, 16, 19). According to various floras (e. g. Prescott et al. 1981, Růžička 1981), there are but very few Actinotaenium species known to have such spinous zygospores, so it is a most relevant diagnostic feature. Presumably, because of their extremely small cell dimensions, vegetative populations of A. spinosporum are easily overlooked or misidentified. For instance, A. perminutum (G. S. West 1914: 1041) Teiling (1954: 410) as described in Szelag-Wasielewska & Tomaszewicz (2003) does not concern A. perminutum but most likely A. spinosporum.	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9AB369FF4CFB528A7C6FD1.taxon	biology_ecology	Ecology: — In the type locality ‘ Baggelhuizen’ an abundantly sporulating population of A. spinosporum was encountered in spring 2010. Later on, sporulating populations of this species were also found in a shallow pool in a former agricultural land (53.106 ° N, 6.648 ° E, pH 6.4, conductivity 58 µS cm - 1) and in small pools on the site ‘ Hondstongen’ (53.106 ° N, 6.570 ° E; pH 5.4, conductivity 47 µS cm - 1). Bijkerk & Bultstra (2012) appear to have found a stable population of this species in the ‘ Besthmenerven’ for many years (52.495 ° N, 6.444 ° E, pH 4.2 – 5.5, conductivity 21 – 30 µS cm - 1). This highly acidic, oligotrophic site differs in habitat from our oligo-mesotrophic and less acidic Drenthe sites. Maybe this species has a rather wide ecological range.	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9DB36CFF4CFF6E8D4A6EFF.taxon	description	Cells in frontal view about as long as broad, deeply constricted. Sinus widely open, more or less rectangular. Semicells 3 - angular in outline. Semicell body gradually passing into robust, diverging arm-like processes that are 2 – 4 - furcate at the end. Cells in apical view 3 - radiate. Cell wall smooth. Zygospores irregularly elongate with broadly rounded angles. Dimensions: length of the cell body (without processes) (9 –) 11 – 15 (– 17) µm, isthmus breadth 7.0 – 8.5 µm. The mature zygospore measures 23 – 27 × 13 – 16 µm.	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9DB36CFF4CFF6E8D4A6EFF.taxon	materials_examined	Type: — THE NETHERLANDS. Drenthe: Borger, Meindersveen, 52.936 ° N, 6.728 ° E, pH 4.6, conductivity 60 µS cm - 1, Van Westen, 29 August 2009 (holotype L! Hugo de Vries Lab 2013.02, preserved as a fixed natural sample).	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9DB36CFF4CFF6E8D4A6EFF.taxon	diagnosis	Differential diagnosis: — As the name of the newly described species indicates, it resembles Staurastrum brachiatum Ralfs (1848: 131). The latter species is known to be highly polymorphic. Presumably, a number of different formae and varieties described under that species name represent species of their own (Coesel & Meesters 2013). In our Drenthe investigation several morphotypes could be distinguished, differing in cell size and markedness of the furcate ends of the processes. One of these types, characterized by relatively large cells and spiny zygospores, obviously is identic with Staurastrum brachiatum as originally described in Ralfs (1848), (Figs. 28, 29). A second type, consistently smaller in cell size and with less pronounced furcate ends (Figs. 2, 3, 4, 26) appeared also to differ in the shape of its zygospore. Instead of a quadrate spore furnished with a number of stout spines as in St. brachiatum, the zygospore of our species under discussion is more elongate with broadly rounded angles lacking any trace of spines (Figs. 5, 6, 7, 27). Particularly this deviating type of zygospore led us to describe this alga as a new species. Application of the t-test to differences in cell length (apex to apex) showed a significant difference (p <0.001) between both species (Fig. 30).	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9DB36CFF4CFF6E8D4A6EFF.taxon	biology_ecology	Ecology: — In the province of Drenthe, St. brachiatoides appears to be much more widely distributed than St. brachiatum. Staurastrum brachiatum was found in only three areas in the province of Drenthe. Surprisingly, all locations were shallow oligotrophic to mesotrophic pools on former agricultural land with pH values between 5.0 and 6.5. Staurastrum brachiatoides is very common in acidic oligotrophic moorland pools with pH 4.0 – 5.5. Application of the t-test to differences in the pH of 14 locations showed a significant difference (p <0.002) between both species (Fig. 31). In the meantime, sporulating St. brachiatoides is also known from several sites in the Dutch province of Noord-Brabant and most likely, judging from vegetative cell characteristics (dimensions), in the Netherlands St. brachiatoides is much more common than St. brachiatum.	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9EB36CFF4CFB488A036897.taxon	discussion	Staurastrum echinatum, published by Ralfs (1848) on the basis of drawings made by Alphonse de Brébisson, is a rather rare, spiny Staurastrum that in former times repeatedly was confused with other species. This was mainly due to Ralfs’ extremely concise description. It was Heimans (1926) who, examining Brébisson’s original exsiccata, provided a much more detailed characterization of this species rendering reliable identification a lot easier. So far, no zygospores were known of St. echinatum (Coesel & Meesters 2013). The zygospore attributed to this species by Grönblad (1920, pl. 1: 38 – 40) clearly refers to an other species, presumably Staurastrum teliferum Ralfs (1848: 128). In the Dutch province of Drenthe, St. echinatum (Figs. 22, 23) is less rare than elsewhere in the Netherlands. In some samples it was even of abundant occurrence, e. g. in a sample originating from military training area ‘ De Haar’, collected 5 January 2013. It was in this sample that we encountered some conjugating specimens. The zygospores may be characterized as about globose and provided with stout protuberances. Those protuberances are conical, passing into a spine that is repeatedly bi- or threefold truncate (Figs. 1, 24, 25).	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9EB36DFF4CF9348DB46CE7.taxon	description	Cells in frontal view about as long as broad, deeply constricted. Sinus widely open, more or less rectangular. Semicells 3 - angular in outline. Semicell body cup-shaped, the apical angles produced to form slender, divergent processes. Processes with hardly noticeable undulate / dentate margin. Cells in apical view 4 - radiate with concave sides. Dimensions: length 20 – 23 µm, breadth 22 – 27 µm.	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9EB36DFF4CF9348DB46CE7.taxon	materials_examined	Type: — THE NETHERLANDS. Drenthe: Assen, pool in district Marsdijk, 53.018 ° N, 6.600 ° E, pH 7.5, conductivity 80 µS cm - 1, Van Westen, 23 May 2008 (holotype L! Hugo de Vries Lab 2013.03, preserved as a fixed natural sample).	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
03ABFF6FFF9EB36DFF4CF9348DB46CE7.taxon	diagnosis	Differential diagnosis: — Staurastrum quadriradiatum is a small-sized Staurastrum species that can be compared with St. minimum Coesel (1996: 23). Both species are very delicate in their morphology and display a corresponding cell shape. Light microscopically, almost no trace of ornamentation is to be seen. The most striking difference is in the number of processes: three in St. minimum, four in St. quadriradiatum (Figs. 8, 9, 10). As in other 4 - radiate Staurastrum species, cell morphology is differently expressed depending on the position of the cell observed. Usually cells are seen when resting with one of their processes on the substrate (position 1, see Coesel & Meesters 2013: 42). Their appearance is different when resting on two processes (position 2), compare our Figs. 9 and 10. Another differentiating feature with respect to St. minimum could be in the ornamentation of the processes. While the processes in St. minimum are tipped with small but distinct dentations, those in St. quadriradiatum are seemingly without ornamentation at the top. Only SEM pictures of St. quadriradiatum reveal that the extremities of the processes are not perfectly smooth (Figs. 20, 21). Finally, but certainly not the least important difference, is in the ecology of the two species. Whereas St. minimum is described from acidic, oligotrophic moorland pools (Coesel 1996), St. quadriradiatum was abundantly encountered in an artificial, eutrophic pool, the biocenosis of which was dominated by zooplankton and chlorococcalean green algae. Later on, this species was also found on three other localities in Drenthe. One of these was a former, shallow sand pit filled with water. The other locations were shallow, sandy pools at the margin of the built-up area of villages. All locations were used for recreational purposes.	en	Westen, Marien Van, Coesel, Peter (2014): Taxonomic notes on Dutch desmids VI (Streptophyta, Desmidiales): new species, newly described zygospores. Phytotaxa 166 (4): 285-292, DOI: 10.11646/phytotaxa.166.4.4, URL: http://dx.doi.org/10.11646/phytotaxa.166.4.4
