NOSTOCE.E. 231 



Harv. Man. p. 184. Born. & Thuret Notes Alg. p. 99. 



Nostoc parietinum, Rabh. Alg. Ear. ii., 178. 



Anabaena granularis, Kutz. Tab. Phyc. i., t. 94, f. 6. 



Nostoc granulare, Rabh. Alg. Ear. ii., 163. 



Nostoc tepidariorum, Braun. in Rabh. Alg. No. 2461, 2462. 



On mosses and on walls in greenhouses, &c. 



Plate XC I. fig. I. Nostoc humlfiisnm, nat. size; fig. 2, trichome x 

 400 ; fig. 3, portion of trichome x GOO. 



IV. COMMUNIA. Species terrestrial. Fronds at first globose, 



then tongue-shaped^ plane or irregular. 



Nostoc commune. Vaucli. Con/, p. 222, t. 16,/. 1. 



Adult frond sub-orbicular, folded, undulating, entire or lobed, 

 often perforated, olive, yellowish-brown, or becoming brownish. 



Trichomes flexuous, loosely interwoven, pale blue-green. 

 Joints spherical, compressed, uniform. Heterocysts globose. 



SIZE. Joints, '0045-'006 (usually -005) mm., heterocysts 

 007 mm. 



Rabh. Alg. Eur. ii., 175. Hass. Alg. t. 74, f. 2. Borzi. 

 Alghe Fico. p. 284. Eng. Bot, i., t. 2556, pi. p. 1625. Eng. 

 Bot. i., t. 461. Relh. Cant. 441. Lightf. Fl. Scot. 898. Purt. 

 Midi. Fl. ii., 612. Abbot. Bedf. 271. With. AIT. iv., 80. 

 .Tenner Fl. Tunb. Wells, 190. Harv. Man. 183. Johnst. 

 Fl. Berw. ii., 262. Grev. Fl. Edin. 322. Mack. Hib. 245. 

 Flor. Dev. ii., 49. Eng. Fl. v., 398. Dickie Bot. Guide, 310. 



Tremella nostoc, Linn. sp. 



Nostoc cinifionum, Born. & Thuret Notes Alg. ii., 102. 



Nostoc foliaceum, Ag, Syst. Alg. p. 19. Hass. Alg. t. 76, 

 f. 2. Rabh. Alg. Eur. ii., 173. Eng. Fl. v., 399. Harv. Man. 

 183. Mac. Hib. 245. Dickie Bot. Guide, 310. 



Nostoc arctum, Kutz. Tab. Phyc. ii., t. 7, f. 1. 



No-stoc littorale, Kutz. Tab. Phyc. ii , t. 8, f. 1. 



Nostoc prismaticum, Ces. in Rabh. Alg. Eur. ii., 169. 



Nostoc riigosum, Kutz. Tab. Phyc. ii., t. 11, f. 1. 



Nostoc salswn, Kutz. Tab. Phyc. ii., t. 8, f. 3. 



On wet ground. 



Plate XCL fig. 4. Nostoc commune, nat. size ; fig. 5 trichome x400 ; 

 fig. 6, portions of trichome x 600, fig. 7, portion of trichome. 



V. SPH.ERICA. Fronds globose or subglobose (becoming irregular 

 when they grow large), limited by a firm and resisting peridermic 



coating. 



Nostoc sphaericum. Vaucli. Conf. 223, t. 16, /. 2. 



Fronds firm, sphserieal, about the size of a pea, gregarious, 

 olive or bluish-green, or brownish, with a firm brownish or 

 colourless periderm. 



2 K 



