184 Ulothricaceae 



may object to the displacement of a traditional name, though we 

 believe this change is based on sound principles. 



Synopsis of Species 



Chromatophores usually numerous, cell-wall thin. 



Diameter of filaments 6-1 1 //. I. T. bombycinum. 



Diameter of filaments 3-6 fi. lb. T. bombycinum f. tenia-. 



Chromatophores 2-4, symmetrically disposed, diameter of cells 5-6 //. 



2. T. minus. 

 Chromatophores numerous, large, cell-wall thicker, diameter of cells 11-16.5 //. 



3. T. utriculosum . 



i. Tribonema bombycinum (Agardh) Derb. & Sol. Mem. sur 



physiol. alg. 18. pi. 4. f. 16-21. 1856. 



Conferva bombycina Agardh, Syn. Alg. Scand. 78. 1817; 

 Syst. Alg. 83. 1824. Kiitz. Spec. Alg. 371. 1849; Tab. Phyc. 

 3 : //. 44. f. 1, 2. 1853. Rabenh. Flor. Eur. Alg. 3: 323. 1868. 

 Wille, Ofvers. Vet.-Akad. Forhand. 1881 8 : pi. p.f 41-43, pL 10. 

 f 51-54, 1881. Lagerh. Flora, 72 : 1g4-20g.pl. 6. 1889. Cooke, 

 Brit. F. W. Alg. 137.//. 53. f. 4. 1883. Wolle, F. W. Alg. 142. 

 //. 121. f. 8, p. 1887. DeToni, Syll. Alg. 1 : 216. 1889. Bohlin, 

 Bihang Svensk. Vet.-Akad. Hand. 23 s : No. 3. pi. i.f. 1-14. pi. 2. 

 f. 44-46. 1897. 



Conferva sordida Roth. Cath. Bot. 1 : 177. pi. 2. f 4. i797-(?) 

 Dillw. Brit. Conferv. pi. 60. i8o6.(?) Lyngb. Tent. Hyd. Dan. 

 138. pi. 46D. i8i9.(?)* 



Filaments forming a sordid, yellowish or green floccose mass, 

 6— 1 1 fj. in diameter when mature ; cells cylindrical or somewhat 

 inflated, 2-4 times as long as the diameter ; chromatophores 

 several in a cell, small or of moderate size, scattered or crowded, 

 glistening oil-drops often numerous : cell-wall rather thin (//. 25, 



/• i-3)- 



Exsic. : Phyc. Bor. Am. 620, Maiden, Mass., April, 1894 



(F. S. Collins). 



Common and widely distributed in stagnant and flowing waters, 

 in spring and fall. 



Connecticut : Thomaston, April ; Watertown, May (563) ; 

 Plymouth, November {666). 



* C. sordida Dillw. was generally regarded as a synonym or variety of C. bomby- 

 cina by the older authors. More recently it has been considered a Microspora. The 

 original description and figures allow no final judgment as to the character of the 

 species, hence it would be better if the name were dropped unless type specimens can 

 be found. A specimen issued as C. sordida Rabenh. Alg. Sachs, no is Oedogonium sp. 



