194 University of California Publications. [botany 



Cylindrospermum sp. f 



In a specimen collected floating on a small pond near Coupe- 

 ville, Whidbey Island, Wash., by Gardner (No. 606), the spores 

 are unripe, but the filaments have heterocysts at both ends. It 

 probably belongs to G. licheniforme (Bory) Kuetzing. 



Family SCYTONEMATACE.E. 



Microchaete tenera Thuret. 



Forming grayish tufts on dripping rocks. Walls of Amaknak 

 Cave, Amaknak Island, Bay of Unalaska, Alaska, W.A.8. and 

 A.A.L., No. 3292! 



The heterocysts are chiefly basal, but there are occasional 

 oblong intercalary ones. The general aspect is that of a 

 Calothrix, but it lacks any indication of a terminal hair. 



Microchaete robusta Setchell and Gardner sp. nov. 



In tufts and stellate clusters on water weeds; filaments 

 elongated and perfectly cylindrical, decumbent at the very base, 

 but scarcely thickened, 16-18 v- in diameter; trichome composed 

 of cells which are quadrate or slightly longer than broad in the 

 lower portion and which are shortened to one-third as long as 

 broad in the upper part, 12 /* in diameter and the cells 6-16 /* 

 long, a?ruginous and filled with fine granules; sheath thin, at 

 first, but later stratified, hyaline; heterocysts basal and inter- 

 calary, the former being spherical or nearly so, while the latter 

 are elongated and rectangular. 



In ponds of fresh water. Near Seattle, Wash., Professor 

 T. V. B. KincaiiJ, No. 768! 



Apparently a very distinct species, and referred to this 

 genus rather than to Calotrhix, on account of the filaments being 

 of uniform width from base to apex. The terminal cells of the 

 filaments are short and torulose, and the uppermost cells are 

 nearly if not quite colorless, reminding one of the terminal hair 

 of the Rivulariaceffi, but the colorless portion of trichome does 

 not taper at all. 



