182 NEMATOPHYCK^E. 



Ulothrix variabilis. Kutz. Tab. Phyc. u.,t. 85, /. 3. 



Pale green ; cells equal or a little longer than their diameter, 

 rarely twice as long ; cell-contents at first always contracted in 

 a quadrate manner. 



SIZE. Cells -005--007 mm. 



Rabh. Alg. Eur. iii. 



Ulotlirix subtilis, var. c. variabilis, Kirch. Alg. Sch. 77. 



Tn ditches and slow streams. 



The view entertained by Kirchner that this and V. tenerrima are 

 only varieties of Ulothrix subtilis is probably correct. 



Plate LXX. fig. 4. Portions of threads of Ulothrix variabilis X 400 

 diam. 



Ulothrix tenerrima. Kutz. Tab. Phy. n., *. 87, /. 1. 



Pale green, or yellowish-green, lubricous ; cells mostly equal 

 in length and diameter, now and then a little shorter. 

 SIZE. Cells -007--01 mm. 

 Rabh. Alg. Eur. iii., 3G6. 

 Uloihrix subtilis ) var. e. tenerrima, Kirch. Alg. Schl. p. 77. 



In ditches, turbaries, &c. 



Plate LXX.fg. 5. Portions of threads of Ulothnx tenerrima X 400 

 diam. 



Ulothrix tennis. Kutz. Tab. Pliyc. n., t. 89, /. 1, bis. 



Dark green, attached, from half to two or three inches long, 

 mucous, cells equal or 2-4 times shorter than their diameter, 

 cell membrane thin, homogeneous. 



SIZE. Cells 017--026mm. 



Rabh. Alg. Eur. iii., 366. Kirch. Alg. Schl. p. 78. 



In ditches and streamlets. 



Plate LXX. Jiff. 6. Portions of threads of Ulotlirix tennis X 400 

 diam. 



Ulothrix (Horxnidium) radicans. Kutz. Tab. Phyc. IT., t. 95, f. 3. 



Yellowish green, rather rigid, densely interwoven in a soft 

 velvety green stratum, cells either nearly equal or 2-3 times 

 shorter than their diameter. 



SIZE. Cells -0075--0095 mm. 



Rabh. Alg. Eur. iii., 367. Kirch. Alg. Schl. p. 77. 



Hormulium murale, Kutz. Phy. Germ. p. 193. 



Lyngbya muralis, Ag. Syst. p. 74. Eng. Fl. v, 370. Hass, 

 Alg. 221, t. 59, f. 7. Eng. Bot, ii., t. 2522. Jenn. Tunb. 



