6 BRITISH DESMIDIACEJE. 



44. Staurastrum apiculatum Breb. 

 (PL CXXIX, figs. 6-8.) 



Staurastrum apiculatum Breb. Liste Desm. 185(5, p. 142, t. 1, f. 23 ; Arch. 



in Pritch. Inf. 1861, p. 737 ; in Q. J. M. S. 1868, p. 67 ; Cooke, Brit. Desm. 



1887, p. 139, t.49, f. 2; Borge, Siissw. Chlor. Archang. 1894, p. 37; Roy 



& Biss. Scott. Desm. 1893, p. 16 ; West & G. S. West, Some N. Amer. 



Desm. 1896, p. 254, t. 16, f. 6 ; Freshw. Chlor. Koh Chang, 1901, p. 92 ; 



. Alg. Yorks. 1902, p. 96 ; Alg. N. Ireland, 1902, p. 44 ; Georgev. Desm. 



Macedonia, 1910, p. 243 ; Borge, Botan. Notiser, 1913, p. 28. 

 St. dejectum var. apiculatum Lund. Desm. Suec. 1871, p. 59 ; Kirchn. Alg. 



Schles. 1878, p. 169 ; Wille, Norges Ferskv. Alg. 1880, p. 40 ; Comere, 



Desm. de France, 1901, p. 161, t. 12, f. 30 ; Him, Desm. Filmland, 1903, 



p. 20, t. 2, f. 30. 

 St. dejectum a Jacobs. Desm. Danem. 1875, p. 203. 



Cells small, about as long as broad, deeply constricted, 

 sinus widely open, with its apex acutely rounded ; semi- 

 cells rather wine-glass shaped, dorsal margin almost 

 straight, only slightly convex, or even a little concave, 

 ventral margin nearly semicircular ; with a minute 

 acute spine at each angle which is dorsal rather than 

 lateral in its attachment, and is directed vertically 

 upwards. Vertical view triangular, lateral margins 

 slightly concave, angles somewhat turgid and provided 

 with a minute mucro at each extremity. 



Zygospore spherical, provided with numerous simple 

 acute spines. 



Length = breadth = 18-29 \L ; breadth of isthmus 5*5- 

 7 \L ; diam. zygosp., without spines, 23 \L ; length of 

 spines 6\i. 



ENGLAND. Cumberland ! Westmoreland (Biss.) I 

 W., N., and E. Yorks ! Cambridge ! Surrey (zygo- 

 spores from Thursley Common) ! Hants (Roy] ! Devon 

 (Harris}. Cornwall (Marquand) I 



WALES.- -Not uncommon ! 



SCOTLAND. General, but scarce ! With zygospores 

 from Slewdrum, Aberdeen (Roy & Biss.}. 



IRELAND.- -Donegal ! Mayo and Clare Island ! Gal- 

 way ! Kerry ! Dublin and Wicklow (Arch.}. Louth ! 

 Down ! Londonderry ! Plankton of Lough Neagh ! of 

 Galway ! and of Kerry ! 



Geogr. Distribution.- -France. Germany. Galicia in 



