STAUEASTRUM. 25 



8t. cuspidatum Borge in Botan. Notiser, 1897, p. 213. 



St. cuspidatum var. longispimun Lemm. Beitr. Kenntnis Planktonalg. 



1898, p. 153. 

 St. Daaei Huitfeldt-Kaas, Plankton Norske Vande, 1906, pp. 55 and 155, 



t. 2, f. 30, 31. 



Cells much larger and isthmus broader than in the 

 type, spines very long and stout, parallel or diverging, 

 sometimes curved. Vertical view triangular, sides only 

 slightly concave or nearly straight. 



Length, without spines, 27-43 \L ; breadth, without 

 spines, 24-30 u. ; breadth of isthmus 4-6 '5 ^ ; length of 

 spines 10-18 pi. 



ENGLAND. - Plankton of Buttermere, Crummock 

 Water, Bassenthwaite Water, and Wast Water, Cumber- 

 land ! Plankton of Brother's Water, Ullswater, C4ras- 

 mere and Windermere, Westmoreland ! Malham Tarn, 

 W. Yorks ! Epping Forest, Essex ! 



WALES.- -In the plankton. 



SCOTLAND. - Rhiconich, Sutherland ! Common in 

 the plankton of Ross, Inverness, Perth, Lewis and Harris, 

 Outer Hebrides, and the Shetlands ! 



IRELAND.- -Plankton of Mayo and Kerry! Plank- 

 ton of Lough Xeagh ! 



Geogr. Distribution. Germany. Scandinavia. Fin- 

 mark. Paraguay. 



This large variety with its strong spines is a very common 

 plankton form. The spines are variable in their inflexion, being 

 usually curved slightly outwards, or sometimes parallel. The 

 forms described by Borge from the plankton of Mull (in ' Botan. 

 Notiser,' 1897, p. 213) probably belong to this variety. 







Var. divergens Nordst. (PL CXXXII, figs. 16, 17.) 



Staurastrum cuspidatum var. divergens Nordst. Desm. Brasil, 1870, p. 225, 

 t, 4, f. 49 ; Gutw. Flor. Glonow Okolic Lwowa, 1891, p. 65 ; West, Freshw. 

 Alg. W. Ireland, 1892, p. 171 ; Roy & Biss. Scott. Desm. 1894, p. 19 ; 

 West & G. S. West, New and Int. Freshw. Alg. 1896, p. 157, t, 4, f. 52 ; 

 Alg. S. England, 1897, p. 492 ; Alga-fl. Yorks, 1902, p. 97. 



Cells rather smaller than in the type, spines con- 

 spicuously divergent ; isthmus variable, elongated or 

 sometimes very short. 



