NOSTOCEJ3 233 



B ormosiphon macrosporus, Kutz. Tab. Phyc. ii., t. 13, f. 1. 

 Diplocolon Heppiij Itzig. Phyc. Stud. t. 11, f. 8-12. 

 Nostoc pyreniacum, Ripart. Bull. Soc. Bot. Fr. (1868.) 

 Nostoc ichthyon, Rabh. Alg. Eur. ii., 164. 



On rocks among moss. 



Plate XC 1 1. Jigs. 1, 2. Involved trichomes of N. macrosporum x 400 ; 

 fig. 3, development of hormogone, x 400, after Borzi. 



Nostoc caeruleum. Lyngb. Hydr. Dan. t. 68, /. B. 



Fronds, small, globose or subglobose Q to 4 lines) , fixed or 

 free swimming, usually gregarious, blue or greenish-blue. 



Trichomes dissimilar, unequal, joints of two forms, the one 

 (young) elongated, the other larger, nearly sphssrical, some- 

 times filled with opaque granules. 



SIZE. Joints '004--007 mm., heterocysts -008 mm. 



Born. & Thuret Notes Alg. p. 114. Rabh. Alg. Eur. ii., 167. 

 Nord. & Wittr. Alg. Exs. No. 98. Grey. Sc. Crypt. Fl. 1. 131. 

 Hass. Alg. 293, t. 76, f. 11, t. 75, f. 10, t. 74, f. 1. Eng. Fl. 

 v., 400. Harv. Man. 183. Gray Arr. i., 352. 



Nostoc ccerulescens, Rabh. Alg. Eur. ii., 168. 



Nostoc ftzigsohnii, Rabh. Alg. Eur. ii., 168. 



On mosses and submerged plants. 



Plate XCII. fig. 4. Plants of Nostoc cceruleum natural size ; fig. 5. 

 trichomes x 400 j fig. 6, portion of trichome x 600. 



Nostoc piunif orme . Ag. Disp. Alg. p. 45. 



Frond from the size of a pea to that of a damson, or larger, 

 olive or dark eeruginous-green, when old becoming blackish- 

 brown, with a coriaceous periderm, and watery within. 



Trichomes loosely interwoven, joints subglobose, compressed, 

 closely connected. Heterocysts globose, usually terminal. 



SIZE. Joints '004-'005 mm., heterocysts < (J06-'007 mm. 



Born. & Thuret Notes Alg. p. 116. Rabh. Alg. Eur. ii. 

 Kutz. Tab. Phy. ii., t. 4, f. 4. Witt. & Nord. Alg. Exs. 97, 

 276. (?) Berk. Glean, t. 19, f. 2. Hass. Alg. 291, t. 76, f. 

 3,4. Eng. Fl. v., 399. Harv. Man. 183. Gray Arr. i., 352. 



Ulva pruniformis, Hiuls. Aug. ii., 572. Abbot. Bedf. 274. 

 With. Arr. iv., 120. Hull. Br. Fl. 310. 



Nostoc coccymelon, Kutz. Tab. Phyc. ii., t. 4, f. 3. 



In freshwater pools, rivulets, &c. 



Plate XCII. fig. 7. Nostoc pruniforme, natural size ; fig. 8. trichome 

 x 400 ; fig. 9, portion of trichome, with spores in course of formation 

 x600. 



