Nr. 1] SUBAERIAL ALGAE FROM SOUTH AFRICA 11 



matophore has oflen distinctly receded from the membrane, which 

 is no doul)t only to be considered as phenomena due to con- 

 Iraction diiring the gradual exsiccation. The edge of the chro- 

 matophore is even, or it mav sometimes be more or less emai-ginate 

 and irregiilarly denticulate, and at times I have seen specinnens 

 with aliiiost reticiilarly latticed chroniatophore. A pyrenoid is want- 

 ing. The nucleus is situated in the centre of tlie cell. The membrane is 

 ahvays very thin and colourless, without a mucous envelope, gene- 

 rally glabrous, l)ut sometimes distinctly crenulate. This crenulation 

 may be local, only limited to certain parts of the membrane, or the 

 latter may be crenulate all over the surface. Small as well as large 

 cells may have crenulate membranes. The size of the cells is rather 

 varjdng, from diminutive to 22 u in diameter. The average size, 

 though, is 8 — 16 fi. The number of the zoospores is very varying 

 according to the size of the mother cell. Their shape is ovoid or 

 ollipsoid, 2 — 3 u in length, and a lateral chroniatophore may some- 

 times be pointed out, filling only about half of the inner part of th>e 

 zoospore (pl.I, fig.51). The zoospores are liberated by the rupture of 

 the mother membrane. In samples of this species vacuous chapped 

 membranes frequently occur (pi. I, fig. 46, 47, 49, 50, 51), which 

 must be considered as em})tied zoosporangies. Thus, the membrane 

 does not gelatinize. Besides in free state, I have also met with this 

 species as lichen-gonidia. 



The species occurs in the foUowing samples: 25. 28, 60, 75, 78, 

 85, 158, 237, 238, 245, 253, 260, 340, 359, 364, 365, 370, 373, 375, 380, 

 383, 390, 400, 401, 402, 403. 



Chlorella vulgaris Hi-.vi;niNCK, Hot. Ztg. 48 (1890) ]). 758. [PI. 

 II, Fig. 90—1041. 



This species occurs sporadically around Durban, but I have not 

 lound it in any of the samjiiles from Saldanha Bay. It thus seems 

 lo be rather rare in the territory investigaled, al least far more rare 

 than e. g. in northern Europe, where the species is, indeed, one of 

 the most frequent algae. The cells measure 7 — 9 u in diameter 

 vvhen fuU-grown; only occasionally they are larger, up to 12 ju. 

 By the growth of the autospores the membrane of the mother cell 

 gels dilated, however, and it may then altain larger dimensions. 

 The characteristic feature of the species is the cup-sliaped or 

 spherical, j^arietal chromatophore, which lines the inner cell-wall 

 and fills it entirely, only leaving a larger or smaller, nearly cir- 

 cular or ovate, colourless opening; a pyrenoid is not distinct. The 

 cell-wall is rather thick and solid, without a mucous envelope, gla- 

 brous, or sometimes finely crenulate all over the surface, oi" only 

 partly so. The autospores are globose and develop in a small num- 

 ber (2 — 8) in the mother cell, and are detached by the bursting of the 

 old membrane. Their diameter is 4 — 5 jn, and when still encoan- 



