Vol.. 1] Set c hell- Gardner. — Alga' of Xorlhivesiern America. 293 



the last in having the interverticiUary filaments developed to 

 such an extent as to obscure the moniliform habit. 



Batrachospermum pyramidale Sirodot. 



Attached to boards and stones in a rapidly running stream of 

 fresh water. Newhall, Orcas Island, Wash., N.L.G., No. 616! 



The verticils are usually globular, distant, and distinct, while 

 the cystocarps vary in size and distance from the center of the 

 verticil, all, however, being included within it. 



Batrachospermum densum Sirodot. 



On stones in a snuill rill of fresh water. Amaknak Island, 

 Bay of Unalaska, Alaska, U'.A.N. and A.A.L., No. 3298! 



The verticils are discoid and confluent below on account of 

 the growth of the interverticiUary filaments. The whole plant is 

 dark purplish green. The cystocarps are small with relatively 

 large spores included within the inner half of the verticil. 



Batrachospermum ectocarpum Sii-odot. 



Attached to stones in running fresh water. Near Dexter, 

 Golofniu Bay, Alaska, R. C. McGregor, No. 5664! ; Chambers 

 Creek, near Tacoma, Wash., N.L.G., No. 427! 



Distinguished by the large cystocarps which are at the outer 

 edge of the verticil, often more or less exserted, but without con- 

 spicuous bracteoid filaments. 



Batrachospermum vagum f. flagelliforme Sirodot. 



In ponds, pools, and streams of fresh water. 

 Kadiak Island, Cook Inlet, and Virgin Bay in Prince William 

 Sound, Alaska, Saiaiders (1901, p. 433). 



Batrachospermum vagum f. keratophytum Sirodot. 



In a stream of fresh water. Near Port Kenfrew, B. C., 

 Tilden, No. T)!,")!, Butler <iiid Pollei/, in Collins, Holden and 

 Setchell. P. B.-A., No. 879a! 



Batrachospermum ccerulescens Sirodot. 



Xooksjiek Kiver, Whatcom County. Wash., X.L.G.. No. 701! 



The material is preserved in formalin, so that the color is no 



longer apparent, but the ])lant, when fi-esli. was decidedly blue, and 



BOT.— 2(1. 



