STAUHASTRUM. 167 



Cell-wall granulate, granules arranged in concentric 

 series around the angles, in the middle of the apex 

 slightly reduced in size. 



o / 



Zygospore unknown. 



Length. 4(>-50//,; breadth 34-40'o/x; breadth of 

 isthmus 911 (JL. 



SCOTLAND.- -At 3500 ft. on Cairngorm, Inverness 

 (Eon $ Bis*et). 



Geogr. Distribution.- -United States. Macedonia (?). 



St. botrophilum is a very characteristic species, very rare 

 in the British Islands, but more frequently observed in the 

 United States. The figure we give (PL CXXYI, fig. 4) is a 

 drawing made from one of Wolle's original specimens which 

 that author sent to us some years ago. 



29. Staurastrum turgescens De Not. 

 (PI. CXXVI, figs. 5, (3.) 



Statirastrum turgescens De Not. Desm. Ital 1867, p. 51, t. 4, f. 43 ; Arch, 

 in Quart. Journ. Micr. Sci. 1878, p. 105 ; Cooke, Brit. Desm. 1887, 

 p. 189, t. 66, f. 4 ; De Toni, Syll. Alg. 1889, p. 1189; West, Alg. N. 

 Wales, 1890, p. 294 ; Alg. W. Ireland, 1892, p. 178 ; Alg. Engl. Lake 

 Distr. 1892, p. 731 ; ? Schmiclle, Beitr. Algenfl. 'Schwarzwald. u. 

 Eheineb. 1893, p. 109. t, 5, f. 28 ; Roy & Biss. Scott. Desm. 1893, p. 20 

 (sep.) ; Nordst. Index Desm. 1896, p. 263 ; W. & G. S. West, Alg. S. 

 England, 1897, p. 494 ; Alga-fl. Yorks. 1901, p. 102 ; Alg. N. Ireland, 

 1902, p. 50 ; G. S. West, West Indian Freslnv. Alg. 1904, p. 286 ; Alg. 

 Third Tanganyika Expedit. 1907, p. 125 ; Hnstedt, Desm. et Bacill. aus 

 Tirol, 1911, p. 337. 



St. pntictidatum Breb. var. turgescens (De Not.) Eabenh. Flor. Europ. Alg. 

 Ill, 1868, p. 2i )S. 



St. punctulatum Breb. var. sulmqnlosum Racib. Nonn. Desm. Polon. 1885, 

 p. 86, t. 12, f . 13. 



Cells rather small, a little longer than broad, deeply 

 constricted, sinus a little open and acute-angled ; semi- 

 cells elliptic or elliptic-oblong. Vertical view triangular 

 (very rarely quadrangular), sides concave, angles 

 broadly rounded. Cell-wall finely granulate, granules 



t/ ... 



fairly dense but without definite disposition. 



Zygospore compressed and smooth, circular in the 

 broad view with 9-12 marginal undulations, in the 

 narrow view oblong-elliptic. 



Length 28-38'5/x,; breadth 25-32-0//,; breadth of 

 isthmus 10-12 p.. 



