52 



MEMOIRS OF THE NEW YORK BOTANICAL GARDEN 



Kirchner {loc. cit., 60), with the same exception, and in addi- 

 tional exception of the lack of multiple trichomes in a common 

 sheath. They become confluent by fusion after formation of the 

 separate sheaths. It is typical Hypheothrix with the exception 

 of the symplocoid habit, a condition which varies considerably 

 with the environment. I am placing it in the last-mentioned 

 genus, awaiting further knowledge of its life history. 



Hypheothrix Willei sp. nov. 



Plate 10, figure 98 



Filaments prostrate, distributed among other algae, about 

 one-half mm. long, 40-60 p diam., more or less irregularly 

 branched, fairly definite and smooth on the surface; trichomes 

 1-3 in a sheath, 5.2-5.4 |j diam., straight, not constricted, long 

 and sharply attenuated at the apices ; cells quadrate to slightly 

 greater or less than the diameter, pale aeruginous, densely con- 

 gested with relatively large granules evenly distributed; cross- 

 walls very thin; 4-6 apical cells forming an acute cone; sheath 

 hyaline in the juvenile stage, changing with age in part to light 

 pink or salmon, homogeneous. 



Growing among other Mijxoplifjceae on rocks west of Huma- 

 cao, )io. 613 b, type. 



In placing this species I have weighed the slight coloration of 

 the sheaths against other characters and decided to place it with 

 Hypheothrix, although that genus has been limited to include 

 only those forms with hyaline sheaths. 



Schizothrix violacea sp. nov. 



Plate 11, figure 99 



Filaments not forming a definite stratum, but associated with 

 other algae, 400-600 \\ long, 7-11 \\ diam., contorted, usually col- 

 lected into small groujjs and more or less adhering to each other, 

 but frequently single and independent, tapering at the apices to 

 a sharp point, unbranclied; trichomes single in a sheath, cylin- 

 drical, 2.3-2.5 n diam., very slightly constricted at the dissepi- 

 ments ; cells quadrate to twice as long as the diamter, homogene- 

 ous, pale olive-green ; cross-walls very thin ; end cell blunt-coni- 

 cal; sheath ample, dark violet, homogeneous, somewhat rough- 

 ened on the margin. 



Growing among other Myxophyceae on limestone between 

 Arecibo and Utuado, no. 1476 g, type. 



