STAURASTRUM. 3 



(at 2,200 ft.), Llyn-y-cwm-nynon and Capel Curig, 

 Carnarvonshire ! 



SCOTLAND. Common (Roy & Biss.). Khiconich, 

 Sutherland ! Shetlands ! 



IRELAND.- -Lough Nacung, Donegal ! Dublin and 

 Wicklow (Arch.). 



Geogr. Distribution. Germany. Austria. Sweden. 

 Asia Minor. United States (var.). 



St. glabrum is a widely distributed but rarely abundant bog 

 species, whose angular form and inflexed spines readily dis- 

 tinguish it from all allied species. 



43. Staurastrum Dickiei Ralfs. 

 (PL CXXIX, figs. 14, 15.) 



Staurastrum Dickiei Ralfs, Brit. Desm. 1848, p. 123, t. 21, f. 3 ; Arch, in 

 Pritch. Inf. 1801, p. 737 ; Rabenh. Krypt. Fl. -Sachs. 18(33, p. 189; Gay, 

 Monogr. loc. Conj. 1884, p. 07 ; \Y>lle, Desm. U.S. 1884, p. 122, t. 40, f. 5, 6, 

 t. 51, f. 20, 21 ; Cooke, Brit, Desm. 1887, p. 140, t. 49, f. 3 ; Wittr. & 

 Nordst. Alg. Exsic. Ease. 21, p. 37, 1889 (forma); De Toni, Syll. Alg. 

 1889, p. 1139 ; Anderss. Sverig. Chlor. 1890, p. 11 ; West, Ahr. \V. Ireland, 

 1892, p. 171 ; Alg. aq. dulc. Lusit. 1892, p. 1503 (forma) ; Liitkem. Desm. 

 Central China, 1900, p. 123, t. 0, f. 28, 29 (forma) ; Comere, Desm. France, 

 1901, p. 162, t. 13, f. 23 ; Schroder, Gallertbilcl. Alg. 1902, p. 168, t. 7, 

 f. 18; G. S. West, Brit. Fivsliw. Alg. 1904, p. 141, f. 52, A-C ; Borge, 

 Siissw. Alg. Spitzb. 1911, p. !'.. 



Didt/ in nl ium (Staurastrum) concergens B trigona Reinsch, Algenfl. Frank. 

 1807, p. 154. 



Staurastrum brevispimun (3 Dickiei Rabenh. Flor. Europ. Alg. 1868, p. 202. 



St. dejectum /3 Dickiei Jacobs. Desm. Danem. 1875, p. 204. 



St. laniatum Delp. Desm. subalp. 1877, p. 135, t. 10, f. 17 (in part). 



St. forcipatum Playfair, NCAV or less-known Desm. X. S.Wales, 1907, p. 182, 

 t. 5, f. 1. 



Cells rather small, about as long as broad, not in- 

 cluding the spines, deeply constricted, sinus open and 

 acute-angled with a slightly rounded apex ; semicells 

 subelliptic in outline, dorsal and ventral margins almost 

 equally convex, or the ventral margin a little more 

 convex than the dorsal ; angles terminating in a short, 

 very slightly recurved spine, directed towards the other 

 semi cell. Vertical view triangular, lateral margins 

 somewhat concave, angles rather inflated, each with a 

 short spine. Chloroplasts one in each semicell, with a 



