448 TJyiiversitij of California Publications in Botany [Vol. 8 



10. Streblonema pacificum Saunders (Orthog. mnt.) 



Plate 41, fig. .53 



Fronds occupying circular areas, 2-4 mm. diam. ; composed of a 

 network of profusely and irregularly branched horizontal creeping 

 filaments, penetrating among the paraphyses and sporangia of the 

 host, giving rise at right angles below to numerous acute branches, 3-4 

 cells long, and above to numerous fasciculately branched filaments 

 extending to the surface of the host and bearing the gametangia ; cells 

 of the horizontal filaments 3.5-4^ diam., somewhat irregular ; cells of 

 the rhizoidal filaments 1-2. S/a diam. ; cells of the erect filaments 

 variable in shape and size, 4-6/a diam. ; zoosporangia unknown ; game- 

 tangia numerous, terminating the erect filaments and projecting 

 beyond the surface of the host, blunt fusiform, 20-28fi long, 4-6/x 

 broad ; loculi uniseriate. 



Growing on the sporophylls of Alaria. Alaska (Yakutat Bay) to 

 California (San Francisco Bay). 



"Streblonema pacifica" Saunders, Alg. Harriman Exp., 1901, p. 

 417, pi. 45, figs, la, 15 ; Setchell and Gardner, Alg. N.W. Amer., 1903, 

 p. 239. 



Superficially Streblonema pacificum Saunders appears like a small 

 Myrio'nema, the plants forming circular masses in the same manner 

 as that genus; The plants are exceedingly difficult to interpret in the 

 stage in which they begin to be visible to the unaided eye, that is 

 when the gametangia are forming. The sporangia of the host are at 

 this time elongating and more or less disturbing the arrangement of 

 the filaments. As far as can be ascertained from the study of mature 

 and nearly mature plants, the circular masses are occupied by a num- 

 ber of individuals instead of a single individual as in the case of a 

 Myrionema. This may not be the case, however. Against this con- 

 clusion the argument might be urged that the groups of plants are 

 too nearly uniform in size and too nearly circular in outline to be 

 composed of a necessarily variable number of plants intermingled, 

 yet this is the way they appear at maturity. More study of the 

 early stages in the life-history will have to be resorted to before the 

 question can be settled. 



Saunders (loc. cit.) figures hair filaments but does not mention 

 them in his description. We have not been able to find any true hairs 

 in the material from California, nor in the portion of the type which 

 we examined. Neither have we been able to find anj^ anastomosing of 



