1922] Setchell-Gardner : Pliycologkal Contributions 355 



fact that they all seem to be of the same age lead us to suspect that 

 they are some sort of abnormalities, or pathological conditions of the 

 gametangia, which will require much more investigation to interpret. 

 We are retaining this in the genus Compsonema on account of the 

 prevailing simplicity of the erect filaments and the abundance of 

 creeping filaments, practically every cell of which gives rise to an erect 

 filament. 



Compsonema fructuosum sp. nov. 

 Plate 36, figure 2 



Frondibus pulvinulos orbiculares aut leviter irregulares, 4-5 mm. 

 diam. formantibus; parte prostrata filamentis tortuosis repentibus 

 irregularitates hospitis superficies arete adhaerantibus ; filamentis 

 erectis simplicibus, dense stipatis, 190-230ju, longis, cellulis cylindricis. 

 8-9/x diam., inferne 2-4-plo, superne 1-2-plo longioribus; chromato- 

 ■phoris taeniatis; pilis veris deuntibus; zoosporangiis sparsis, late 

 clavatis, pedicellatis brevibus e filamentis repentibus oriundis suifultis, 

 55-65/x (usque ad lOO^a) longis. 22-28/* latis; gametangiis in filamentis 

 erectis terminalibus, cylindricis usque ad leviter fusiformibus, obtusis, 

 80-120/* longis, 12-16/* latis; loculis 2— 4-seriatis. 



Growing on the pneumatocysts of Nereocystis Luetkeana. Tomales 

 Bay, Marin County, California. Type, Gardner, no. 3442 (Herb. 

 Univ. Calif., no. 207034), August. 



Compsonema fructuosum, departs from the type of the genus C. 

 gracile Kuckuck (1899, p. 90, pi. VI (12), figs. 6-9) in having a 

 different host, in having no hairs, in having fewer and shorter sterile 

 filaments, in having more gametangia and in having differences in 

 details of measurements. In the abundance and position of the fruit 

 and in the definite circular thallus with compact monostromatic basal 

 layer of filaments, it approaches very closely to a typical Myrionenm, 

 but the multiseriate gametangia represent a stage in development 

 which we have not admitted into that genus. The gametangia occupy 

 a definite zone on the outer ends of the erect filaments. Practically 

 all of the erect filaments bear gametangia. 



At times the basal layer seems to be distromatic, or even poly- 

 stromatic, but careful investigation shows that this appearance is 

 occasioned by the overlapping creeping filaments which follow the very 

 irregular surface of the host, due to the death of its surface layer of 

 cells, probably before the epiphyte took possession. The zoosporangia 

 are very sparse, but specimens have been seen which show undoubted 

 zoospores. 



