Chloro theciacece 



251 



two of which are produced from each mother-cell. Only one long 

 cilium has been observed on the zoogonidia, but it is very probable 

 that another shorter one has been overlooked. The zoogonidia 

 become attached by the end of the long cilium, the latter then 

 forming the stalk of the new unicellular plant. 



The genus closely resembles Peroniella Gobi 1 , which is also an 

 epiphyte, occurring in the mucous investments of Hyalotheca. 

 The cells are, however, smaller than in that genus and their apices 

 are acute or expanded. The general form of the cells is thus 

 different from the rounded cells of Peroniella. 



S. urceolatus West & G. S. West is known from W. Yorkshire and from 

 N. W. Scotland, occurring as an epiphyte on Mougeotia and Sphcerozosma ; 

 diam. of cells 3 4'2 p. ; length 6'5 10'5 p. ; length of hyaline stalk 4 6 p. ; 

 fig. 116. Schmidle 2 has described another species from Germany. 



Genus Characiopsis Borzi, 1895. Most of the plants of this 

 genus were at one time described as species of Characium A. Br. 

 The cells are rounded, ellipsoid, or ovoid, 

 sometimes acuminate at the apex, with a 

 firm cell-wall and a short basal stalk of 

 some thickness. They occur as epiphytes, 

 solitary or gregarious, and there is no 

 vegetative division. Each cell contains 

 several or many small, parietal chroma- 

 tophores of a pale-green colour. Repro- 

 duction occurs by the division of the cell- 

 contents either to form eight (or more?) 

 zoogonidia, which are set free by the disso- 

 lution of the upper portion of the mother- 

 cell-wall, or to form a number of globose 

 aplanospores which become gametangia 

 immediately on liberation, each producing two or four gametes. 



There are a number of species, several of which are known from Britain. 

 Ch. minuta (A. Br.) Borzi is the most frequent; length of cells 17 18 p.; 

 breadth 5-5 p. ; fig. 117 A. Ch. turgida W. & G. S. West is the largest species 

 of the genus; length of cells 36 46 p.; breadth 11'5 16 p.; fig. 117 B D. 



Genus Mischococeus Nag., 1849. The cells are globular and 

 are united by thick tubular stalks of mucilage to form small 



1 Gobi in Scripta Botan. Horti Univers. Imp. Petropolitanae, torn, i, 1866-7, 

 pp. 244250, t. 1. 



2 Schmidle in Hedwigia, Bd xli, 1902, Heft 4, p. 153, fig. A 1. 



B ^ C -^ D 



Fig. 117. A, Characi- 

 opsis minuta (A. Br.) Borzi, 

 from near Peuzance, Corn- 

 wall. B D, Ch. turgida 

 W. & G. S. West, from 

 Keighley Moor, W. Yorks. 

 ( x 500). 



