294 RHODOPHYCEJE. 



FAMILY IV. LEMANEACE^E. 



Fluviatile alga3. Thallus developed from a confervoid pro- 

 thallic filament, setaceous, almost simple, hollow, nodose, having 

 an internal and a cortical layer of cells. Poljspores numerous, 

 collected in branched moniliforrn series, germinating without 

 fertilization. 



GENUS 121. LEMANEA. Bory. (1808.) 



The only genus in the family, with the same characters as above 

 given. 



" The dilated portions of the threads are loosely filled with the spores, 

 which are produced within the frond. The spores are oval, thick-walled 

 cells, joined together to form series, which are very much branched, so 

 that from a central basal row they rise as a complex bush-like mass. The 

 first step, according to Wartmann, in their germination, consists in the 

 elongation of the spore, and the projection of one end, which is soon cut 

 off by the formation of a transverse partition, and constitutes a new cell. 

 This multiplication soon develops into a branched confervoid filament. A 

 large number of these filaments are generally produced in one place at 

 one time, and form a very apparent greenish layer. Finally, certain cells 

 in branches of these filaments swell up and become very much broader 

 than their fellows, undergoing, at the same time, division so rapidly that 

 they become very short. By-and-bye they divide also in the direction 

 of their breadth, so that, instead of a simple series of cells, there arises 

 a compound mass. This is the beginning of the new frond. At first it 

 is dependent upon the parent filament, but soon acquires a root-like pro- 

 cess at the base, and develops rapidly into the complex cartilaginous 

 plant." Wartmann, Beitrage zur Lemanea (1854). 



Lemanea fluviatilis. Ag, Spec. Alg. n. p. -i. 



Simple, or sparingly branched, 3-4 inches long, straight, 

 nodules rather remote, with about three verticillate papillse. 

 SIZE. Spores '04 x '025 mm. 



Rabh, Alg. Eur. in., 411 . Kirch. Alg. Schles. 43. Eng. Fl. v., 

 p. 322. Hook. Fl. Scot, ii., 84. Eng. Bot. ii., t. 2423. Jenner 

 Tnnb. Wells 176. Harv. Man. 119. Johnst. Fl. Berw. ii., 

 246. Mack. Hib. 220. Gray AIT. i., 288. Hass. Alg. 72. 



Lemanea. corallina, Bory Ann. de Mus. xx., t. 21, f. 2. 



Conferva fluviatilis, Dill. Conf. t. 29. Hull Br. Fl. 332. 

 Eng. Bot. i., t. 1763. Huds. Ang. ii., 597. With. Arr. iv., 

 134. Lightf. Fl. Scot. 985. 



Conferva fluviatilis lubrica setosa equiseti facie, Dill. Muse. 39, 

 t. 7, f. 47. 



Nodularia fluviatilis, Grev. Fl. Ed. 300. Fl. Devon, ii., 57. 



Attached to stones, wood, &c,, in streams. 



