STAURASTRUM. 173 



SECTION J. 



Semicells with accessory processes, mostly of dorsal origin. 

 * Processes quite smooth. 



| All the processes short, less than half the diameter of 

 the " body " of the cell in length. 



160. St.furcatum. 



161. St. senarium. 



162. St. gemelliparum. 

 ft Processes longer, nearly as long as the body of the cell 



is broad, and frequently longer. 



163. St. Clevei. 



164. St. Tohopekaligense. 

 ** Processes rough with granules or denticulations. 



t At least the dorsal processes short, and angular processes, 

 never attaining very great length. 



165. St. arcuaturn. 



166. St. subavicula. 



167. St. amphidoxon. 



168. St. meg alo notion. 



169. St. monticulosiuii . 



170. St. diplacanthum. 



171. St. Westii. 

 161. St. senfii-imn. 



172. St. forficulatum. 



173. St. furdgerum. 

 ft All the processes of considerable length. 



174. St. Arctiscon. 



175. St. sexaugulare. 



160. Staurastrum furcatum (Ehr.) Breb. 

 (PL CLV, figs. 1-4.) 



Xanthidium furcatum Ehr. Inf. 1838, p. 148, t. 10, f. 25 ; Menegh. Synops. 



Desm. 1840, p. 224 ; Ralfs, Brit. Desm. 1848, p. 213. 

 ? X. Ehrenbergii Corda, Aim. de Carlsbad, 1840, p. 214, t. 5, f. 36, 37. 

 stnumstrum spinosum Ralfs, Brit. Desm. 1848, p. 143, t. 22, f . 8 ; De Bary, 



Conj. 1858, p. 44 ; Reinsch, Contrib. Alg. et Fung. 1875, p. 90, t. 10, f. 3 ; 



Heimerl, Desm. Alp. 1891, p. 007. 

 Phycastrum (P achy actinium] Ehrenbergianum Nag. Gatt. einz. Alg. 1849, 



p. 128. 



Asteroxanthium furcatum Kiitz. Spec. Alg. 1849, p. 183. 

 Staurastrum furcatum Breb. Liste Desm. 1856, p. 136 ; Arch, in Pritch. 



Infus. 1861, p. 743 ; Rabenhorst, Flor. Europ. Alg. 1868, p. 218 (in part) ; 



Nordst. Norges Desm. 1873, p. 33 ; Kirchn. Alg. Schles. 1878, p. 170 ; 



Wolle, Desm. U. S. 1884, p. 150, t. 40, f. 40, 41 ; Cooke, Brit. Desm. 1887, 



p. 146 ; De Toni, Syll. Alg. 1889. p. 1153 ; West, Alg. N. Wales, 1890, 



p. 16, f. 11 ; Alg. W. Ireland, 1892, p. 174 ; Alg. Engl. Lake Distr. 1892, 



p. 19 ; Roy & Biss. Scott. Desm. 1893, p. 20 ; Liitkem. Desm. Attersees,. 



