1925] Setchell-Gardner: Melanophyceae 481 



The species under consideration has a relatively extensive system of 

 creeping filaments but very much less so than that of a typical Comp- 

 sonema. The creeping filaments do not form a solid disk, but those 

 from different plants are so intertwined that it is impossible to deter- 

 mine the limits of a distinct individual. In this character it resembles 

 an Ectocarpas. The gametangia are like those of a typical Ectocarpas, 

 but since they are mostly short-pedicellate and spring directly from 

 the creeping filaments, as is the case in a typical Compsonema, and 

 because of the relatively extensive system of creeping filaments, we 

 have placed it in the latter genus. 



11. Compsonema streblonematoides S. and G. 



Fronds forming thin, circular cushions, 3-5 mm. diam. ; prostrate 

 portion composed of filaments following closely the irregularities of 

 the host, giving rise below to numerous rhizoidal filaments penetrating 

 to a depth of 300-350/*. among the cells of the host, and above to sterile 

 filaments and gametangia; erect filaments 140-160/* long; cells of 

 erect filaments cylindrical. 8.5-10/* diam., 1.5-3 times as long ; zoo- 

 sporangia unknown; gametangia mostly cylindrical, short-pedicellate, 

 55-70/x long, ll-14/i broad ; loculi mostly 2-seriate. 



Growing on the pneumatocysts of Nereocystis Luetkeana. Mouth 

 of Tomales Bay, Marin County, California. 

 • Setchell and Gardner, Phyc. Cont. Ill, 1922, p. 353, pi. 35, fig. 4. 



Compsonema streblonematoides, like a Streoloncma, has a large 

 part of the vegetative portion of the frond within the host -plant, the 

 penetrating filaments extending into the host two or three times as far 

 as the length of the external vegetative filaments. The whole frond, 

 however, is the result of the growth of a single cell and forms a com- 

 pact monostromatic basal disk. In the character of the gametangia it 

 is close to a Myrionema, but in a very large majority of cases the 

 loculi are biseriate. 



12. Compsonema sporangiiferum S. and G. 



Fronds forming circular cushions, 1-4 mm. in diameter; prostrate 

 portion composed of compact, irregular, more or less contorted fila- 

 ments following the irregularities of the surface closely, monostro- 

 matic or in part distromatic ; erect filaments 300-700/x long, un- 

 branched or bearing above a few short, mostly secund, fructiferous 

 ramuli ; cells of the erect filaments 6-8/*. diam. at the base, and 2-3 



