266 NEMATOGENS. 
eruginous green, joints shorter than broad; sheaths thick, 
golden brown, often encrusted with deposit of lime. 
Size. Trichomes -008 mm., including sheath -01 mm. 
Kirch. Alg. Schl. 225. Rabh. Alg. Eur. ii., 247. 
Scytonema Julianum, Wittr. & Nordst. Alg. Exs., No. 273 a. 
Drilosiphon muscicola, Kutz. Sp. 302. 
Oscillaria cyanea, Hass. Alg. 248. Eng. Fl. v., 374. Harv. 
Man. 163. 
Conferva cyanea, Eng. Bot. ii., t. 2578. 
Humida cyanea, Gray. Arr. i., 282. 
On walls, stones, overrunning moss, &c. 
Found on the walls of warm honses in the Royal Botanic Gardens at 
Kew, and in Regent’s Park. This is evidently the Conferva cyanea of 
English Botany found on damp walls in-churches, &. ‘On the wall it 
is conspicuous for its light sky-blue colour, like some sort of -VWuror. 
Under a high magnifier, and when moistened, it is found to consist of 
minute even simple entangled threads, coated with a frequently inter- 
rupted covering of a dull glaucous green hue, under which the thread 
itself appears of a lighter glaucous bluish colour, very even in thickness, 
and surface consisting of scarcely distinguishable joints about as broad 
as they are long.”—Smith. 
Bornet and Thuret refer this to a variety of Scytonema Hoffmanna, 
whilst Kirchner retains Meneghini’s specific name, which Thuret thinks 
to belong to Scytonema ocellatum, Lyngbye. 
Plate CVT. fig.1. a, trichomes X 400; 4, portions of same X 400; c, 
hormogones X 400. 
Scytonema interruptum. Thi. 
Intense blue-green, forming a stratum of the same colour ; 
sheath cellular, and furnished throughout its entire length with 
numerous branched and anastomosing rootlets; trichomes dis- 
tinctly annulate, interrupted here and there by heterocysts, 
branches in pairs arising from the protruded trichome. 
Size. Nowhere stated. 
Rhizonema interruptum, Thwaites .in Eng. Bot. ii. Supp., t. 
2954. 
Calothrix interrupta, Carm. Eng. Fl. v., 368. Harv. Man. 
158. 
Stigonema interruptum, Hass. Alg. 229, t. 69, f. 2. 
In wet heathy places, coating mosses, &e. 
We have seen no specimen of this, which is evidently a close ally of 
S. cinereum. The figure is reproduced from English Botany. 
Plate CVI. fig. 2. Scytonema interruptum, after the figure t. 2954, 
English Botany. Considerably magnified, presumably about 360 diam. 
