466 University of California Publications in Botany [Vol. 8 



(Rke.) Fosl. which he found growing on Delesseria sangtdnea at 15 m. 

 depth. He states that the assimilation filaments are 100-125,/i, long 

 and 4-6f(, broad, but gives no measurements for the gametangia. 



The plant which we have diagnosed is doubtless very closely 

 related to Eeinke's Ascocyclus halticus. It may be a distinct species, 

 but we have listed it as a form of halticus until we can obtain more 

 knowledge of its variation, and more authentic information concern- 

 ing the type material of halticus. The particular distinguishing 

 character is the very frequent occurrence of lateral gametangia 

 arising very close to the base of the vegetative filaments. 



13. Myrionema balticum f. pedicellatum S. and G. 



Fronds forming microscopic cushions 150-400/i. (up to SOOju,) diam., 

 very irregular in outline ; erect filaments short-pilif erous in part, 

 140-1 60jtt long; true hairs unknown; zoosporangia (?) narrowly 

 clavate, sessile on the creeping filaments, or terminal on the erect fila- 

 ments ; gametangia terminal on 10-15-celled pedicels, rarely sessile, 

 up to ISO/x long. 



Growing on the outer ends of the leaves of Phyllospadix sp. Point 

 Carmel, Monterey County, California. 



Setchell and Gardner, Phyc. Cont. II, 1922, p. 341, pi. 33, figs. 

 11, 12. 



This form differs from the species in the absence of hairs, in having 

 a few very short-piliferous, vegetative filaments, and in having the 

 gametangia on long pedicels. 



In this form, as in many others, the correct interpretation of the 

 zoosporangia mentioned above in the diagnosis is an open question. 

 They are filled with dense cell contents and, although none has been 

 observed to produce zoospores, they appear as though they might 

 later. Whatever their nature may finally prove to be, they represent 

 another character in which this form differs from the species. Reinke 

 neither figures nor describes them in Ascocyclus halticus. They 

 appear on the same individuals with the gametangia or on different 

 individuals. 



