292 RHODOPHYCE^:. 



" In no other Conferva is the number of the filaments so considerable 

 as this. Their total diameter equals that of the largest horsehair. They 

 divide in every direction from a little disc, ramify to infinity, observing 

 remarkably well the dichotomous disposition in their first division, their 

 branches becoming subsequently vague. Their total length extends even 

 to four inches. 



" From their origin even to their extremity these filaments are clothed 

 with microscopic branches, so impacted that the whorls are not apparent 

 in scarcely any direction ; with a simple lens they are not better dis- 

 covered, from which it might be supposed that one was observing a 

 Thorea. It is but towards the points of the branches that, by the assist- 

 ance of a strong lens, they are at last distinguished. These whorls are 

 very closely approximated, horizontal, compressed the one upon the 

 other, and becoming so confused as to form around the filament, which 

 is green or yellow, and very flexible, a continuous down, mucous to the 

 touch, sometimes very pale, more frequently of a very agreeable bluish 

 watery green ; this colour is, moreover, deep towards the point of the 

 branches. As it grows old the plant tiirns yellow, and is discoloured." 

 Bory. 



var. keratophytum. Bory. 



Beautiful blue-green, thin, very much branched, dichotomous, 

 with the black setaceous base naked, branches all equal, slender, 

 thin, apex slightly incrassated, whorls distinct. 



SIZE. Cellules clavate, about -03 x '015 mm. 



Batrachosperma keratophyta, Bory Ann. Mus. xx., t. 31, f. 2. 



Batrachospermum suevorum, Kutz. Spec. 536. 



Habit, colour, and ramification of B. vagum, but with the whorls dis- 

 tinct. 



Plate CXXV. fig. a, portion of filament X 30 ; b, portion X 200 

 diam. 



Batrachospermum atrum. Harv. Nan. 119. 



Violet-coloured when moist, dark brown, almost black when 

 dry, vaguely and much branched, reaching 2 inches, whorls 

 abbreviated, distant ; interstitial branchlets very short, one or 

 two-celled. 



SIZE. Cellules '012 mm. diam. 



Jenner Tunb. Wells 176. Hass. Alg. 114, t. 16, f. 4. 



Conferva atra, Dillw. Conf. t. 11. Hull Br. Fl. 332. Huds. 

 Ang. ii., 597. Eng. Bot. i., t. 690. With. Arr. iv., 134. 

 Gray. Arr. i., 330. 



Batrachospermum detersum, Eng. Bot. ii., t. 2543. 



Batrachospermum moniliforme, v. detersum, Eng. Fl. v., 388. 

 Mack. Hib, 221. 



Batrachospermum moniliforme, var. i. atrum, Rabh. Alg. Eur. 

 iii., 406. Kirch. Alg. Schles. 45. 



Lemanea setacea, Bory Ann. de Mus. t. 23, f. 3. 



In streams and ditches* 



Plate CXXV I t fig. \. a , portion of filament X 30 ; 6, portion X 200 



