LYNGBY^E. 261 



On moist rocks where the water is constantly trickling, and in 

 mountain streams. 



Carmichael writes of his specimens, " Stratum extensive, slimy, re- 

 markably tough and elastic, black on the surface, ash-coloured under- 

 neath, when dry blackish green. Filaments pale green, straight, or 

 variously curved, radiating, but not equally in all directions." 



Plate CI. fig. 2. Portions of trichomes X 400. 



Lyngbya corium. (Ag.) 



Stratum toughly membranaceous, compact, brown, steel blue 

 or greenish, interwoven forming a mucilaginous membrana- 

 ceous substratum ; trichomes straight or flexuous, rather rigid, 

 olive or brown, then yellowish, joints not more than half as long 

 as broad, beautifully transversely punctate, granulated, apex 

 conically attenuated, bearded. 



SIZE. Trichomes 007--OOS mm. diam. 



Phormidium corium, Ag. Syst. p. 64. Kabh. Alg. Eur. ii., 

 126. 



Oscillatoria corium, Hass. Alg. 252. Eng. Fl. v., 377. 

 Harv. Man. 166. Eng. Bot. ii., 187. Grev. Fl. Edin. 303. 

 Mack. Hib. 240. 



On the rocky bottom of alpine rivulets. 



" Stratum thick, tough, dull brownish, occasionally streaked with pale 

 green, which in some varieties is the prevailing colour, slightly glossy 

 when dry ; filaments slender. In some situations it radiates in fascicles 

 from its whole upper surface ; in others it is found almost denuded 

 of radii, and forming a compact leathery stratum." Harvey. 



Plate CI1. fig. 2. Portions of trichomes X 400. 



Lyngbya turfosa, (Carm.) 



Forming a thick intensely green stratum, with a tough, slimy, 

 ochre-coloured substratum. Trichomes slender, more or less 

 curved, and mostly hyaline at the point ; joints not more than 

 half as long as broad, distinct. 



SIZE. Trichomes '008 mm. diam. 



Oscillatoria turfosa, Carm. in Harv. Man. 164. Hass. Alg. 

 253, t. 72, f. 6. 



On floating sods in old turf pits. 



" This species grows in a thick, intensely green layer, over a tough, 

 slimy, ochre-coloured substratum. It entirely enveloped the sods, some 

 of which were a foot and a-half in diameter. Filaments very slender, 

 more or less curved, and mostly hyaline at the point." Carm. 



Plate Cll. fig. 3. Portions of trichomes X 400, from the original 

 specimens. 



