268 NEMATOGENS. 
On naked ground, overruning mosses, &c. 
Found in some quantity in one of the stoves of the Royal Botanic 
Gardens, Regent's Park, forming a dark velvety stratum on the stones, 
walls, &c. 
Plate CVII. fig. 2. a, slightly enlarged, as seen by aid of a pocket 
lens; b, trichomes X 400; ¢, portion of same; d, hormogones X 400. 
Genus 110. TOLYPOTHRIX. Kutz. (1843.) 
Trichomes spuriously branched, pseudo-branches spreading. 
Ramifications rarely geminate, oftener solitary, and originating 
at a point where the continuity of the trichome is interrupted by 
heterocysts, one or several heterocysts placed directly above 
each branchlet. 
Tolypothrix flaccida. Kutz. Phyc. Gen., p. 228. 
Cespitose, dark blue-green, trichomes and pseudo-branches 
elongated, flaccid, arising from a prostrate base, internally pale 
blue-green, either interrupted or torulose, distinctly articulate 
(when treated by iodine), joints a little shorter than broad, 
sheaths colourless, hyaline, rather broad, heterocysts towards 
the base, subglobose or oblong, two or three together, colour- 
less. 
Size. Trichomes ‘01 mm. 
Rabh. Alg. Eur. ii., 227. Kutz. Tab. Phye. ii, t. 32, f. 2. 
In pools, &c. 
Plate CVIILI. jig.1. Portions of trichomes x 400 diam. 
Tolypothrix distorta. Kutz. Tab. Phyc.1t., t. 33, f. 5. 
Cespitose floccose, bright blue-green, now and then becoming 
pale, trichomes and pseudo-branches very loosely interwoven, 
internally blue-green, sometimes apparently continuous, some- 
times distinctly articulate ; joints equal or a little shorter than 
their diameter; sheaths broad, colourless, rarely pale yellow ; 
heterocysts at the base, or interjected, subglobose or oblong, 
often 2-3 together. 
Size. Trichomes ‘012 mm. 
Rabh. Alg. Eur. ii., 275. Kirch, Alg. Schl., 228. 
Conferva distorta, Dillw. Conf. t. 21. Eng. Bot. t. 2577. 
In swamps. 
“Found cccasionally in boggy pools, growing on thick continuous 
tufts, on decaying grass, and about the stems of aquatic plants, upon 
small fragments of which it often floats in the autumn on the surface of 
the water.” 
Plate CVILI, fig.2 Portion of trichome with hormogone x 400 diam. 
