Contributions to Our Knoiuledge of the Freshwater Algae of Africa. 65 
Genus MICEOCOLEUS Desmazieres. 
1. Microcoleiis chthonoplastes, Thuret, Essai d. classif. d. Nostocliinees, 
Ann. sci. nat., ser. 6, Bot., i, 1875, p. 378 ; Gromont, op. cit., xv, 1893, p. 353, 
PI. XIV, figs. 5-8. 
Sample 324 (rare, on Phormidium fragile) . 
Diam. trich., 6 
Genus SCHIZOTHRIX Kuetzing. 
1. Schizothrix calcicola, Gomont, op. cit., p. 307, PI. YIII, figs. 1-3. 
Sample 345 (common). 
(2) NOSTOCACEAE. 
Genus NOSTOC Vaucher. 
1. Nostoc caerideiim, Ljngb. ; Bornet et Flahault, Eev. d. Nostoc. 
lieterocyst., Ann. sci. nat., Bot., ser. 7, vii, 1888, p. 213 ; Forti, op. cit., 
p. 416. 
Sample 82. 
2. Nostoc muscorum, Agardh, Disp. Alg. Suec, 1812, p. 44; Bornet et 
Flahault, op. cit., p. 200; Forti, op. cit., p. 400. 
Sample 85 (with spores). 
In sample 87 there occurred another Nostoc which may possibly belong 
to this species ; the material, however, showed no spores and was poorly 
preserved. 
3. Nostoc sp. (verrucosum (L.), Vauch. ?). 
Sample 335. 
In the absence of spores it is not possible to make sure of this determina- 
tion. The trichomes were very regularly cylindrical, the cells depressed- 
spherical, and the heterocysts spherical. Diam. cell., 4 fi ; diam. lieterocyst., 
7-8 /i. 
Genus ANABAENA Bory. 
1. ? Anabaena iiiaequalis (Kuetz.), Bornet et Flahault, op. cit., p. 231. 
(Fig. 27.) 
Sample 29 (for the most part epiphytic on Oedogonium sp.). 
This is the same form as has been recorded from Camps Bay in the Cape 
Peninsula and from Riet Eiver, Orange Free State (c/. Fritsch, loc. cit., 
p. 578). It has a marked epiphytic tendency, occurring in the present 
sample mainly on a species of Oedogonium. The trichomes are often rather 
straight and are provided with a delicate close-fitting sheath (Fig. 27, B) ; 
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