Nr. 1] SUBAÉRIAL ALGAE FROM SOUTH AFRICA 17 
The specimens from these different localities evinee in their broad 
features a close congruity. The cells are joined in rather long and 
usually straight filaments, consisting of up to 100 cells or more. 
The cells are on an average 8—9 u broad, and nearly equally long 
— up to twice as long as broad, rarely shorter than broad. The 
filaments are equally broad, at times slightly constricted at the 
dissepiments. The chromatophore is entire at the edges, and the 
comparatively large pyrenoid rather easily discerned. I have 
observed some few specimens forming zoospores. These arise singly 
in each cell, as described and delineated by Wirrz: Om Udviklingen 
af Ulothrix flaccida Körz. (Svensk Bot. Tidskrift 1912), and I have 
nothing to add to what is already known from these investigations. 
Besides this one I have found a somewhat different form: cellulis 
passim tumidis Gay, Alg. Vert. (1891) p. 97, på. XI, fig. 106. 
In pl. VI, fig. 233—243 I have drawn a series of specimens of 
this one. Here the filaments are composed of very few cells only, 
usually 2—4, rarely with up to 8—12 cells in each filament. Very 
frequently are also to be found single cells — akinetes — of an 
ovoid-globose shape. At the fracture the cells are very quickly 
inflated, but often there is to be found on these akinetes small 
inspissations in the membranes on each side, as the membrane will 
also be seen to be flattened. These akinetes divide by a cross-wall, 
and grow directly into new filaments. The breadth of the cells varies 
between 6—10 ;s, on an average 7—8 mu, and the length is commonly 
equal to the breadth, but varies between one half to nearly twice the 
breadth. 
I suppose this latter form is identical with Stichococcus dissectus 
Gay, 1.c. p. 96—100 (HHormidium dissectum (Gay) CHODAT). Cultures 
show that the degree of dissociation of the cells is dependent on the 
natural conditions of the habitat, and this character is therefore 
without any systematical importance whatever. 
Collected on decayed wood above Bluff, near the Signal station 
at the entrance of the harbour of Durban, Oct. 28th (no. 24). 
Stichococcus bacillaris Nicerr f. minor (NÄGELr) sec. CHODAT, 
Monogr. d'Algues en Culture Pure p. 155 (Matériaux pour la Flore 
Cryptogamique Suisse, Vol. IV. Fasc. 2, 1913): HrrrinG, Ulothrica- 
les, ete. in PascHEr, Siusswasser-F1. H. VI, 1914, p. 52, Fig. 66. 
Under this name I class åa small alga I have found in some 
samples of bark and decayed wood from Bluff (Durban), and at 
Ostenwald, Saldanha Bay (nos. 145, 340, 343). The cells are always 
single, small, usually 2,3—3,2 u broad, and 5—8 u long. Their shape 
is somewhat varying, almost cylindric and straight, with obtuse 
ends or slightly curved and oblique, sometimes more elliptic, . 
broadest about the middle. It also happens that one end of the cell 
may be more narrow and pointed than the other one, by which 
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