SCYTONEMA. 253 



cons or olivaceous, slightly curved, ascending ; the internal 

 trichome aeruginous, distinctly articulate with the terminal 

 five or six joints sometimes reddish. Branches mostly gemi- 

 nate, often very long, flaccidly erect, about half as thick as 

 the stem. Sheath of trichomes thick, distinctly lamellate 

 of older plants, smooth, firm, yellowish fuscous. Sheath of 

 the branches paler and thin, with the apex colorless, short 

 and obtusely rounded. Heterocysts about equal to the 

 diameter of the internal filaments. 



Diameter of filaments average, 25-33 /*. 



Moist ground in extended patches, and dripping rocks, 

 Pennsylvania; North Carolina; Ravenel. 



Syn. Conferva myochrous, Dillw. 



Plate CLXXXII, figs. 1, 2, 3, different sizes, single and 

 twin branched. 



SCYTONEMA GRACILE, Kg. 



Stratum thin, dark brown, often forming several inter- 

 woven layers. Filaments much entangled ; pseu do- branch - 

 lets mostly single ; cells often 2-3 times longer than broad, 

 but most frequently indistinct, dull aeruginous, somewhat 

 contracted at the ends, and often of a brownish red color. 

 Sheaths yellow brown, smooth ; heterocysts somewhat ovate, 

 brown. 



Diameter of filaments, with sheath, 9-15 u. 



On rocks bordering ponds, about the water line, also on 

 moist earth. 



Plate CLXXXY, figs. 1-4, after specimens collected on the 

 rocky shores of Morris Pond, New Jersey. 



SCYTONEMA TURFOSUM, Kg. 



Stratum brownish black ; filaments thicker than the pre- 

 ceding ; articulations about as long as wide, sheath thin and 

 close at first, then wider, and later the internal trichome is 

 much contracted, occupying only about one-fourth of the 

 diameter of the Sheath. Filaments vary greatly in thick- 

 ness, from 11-22 yu ; of reddish brown color. 



Turfy strata on exposed earth, and moist rocks. 

 Plate CLXXXV, figs. 5-7, medium sized filaments. 



SCYTONEMA CHEYSOCHLORUM, Kg. 



Stratum crustaceous, olivaceous brown or blackish. Fila- 

 ments flexuously curved and interwoven ; irregularly and 



