364 University of California rnhlications in Botany [Vol. 7 



filamentorum eroetorum evlindricis non constrictis. basi 5.5-8. 5/x diam., 

 in part(^ latioro. lO-17/i diam., 1.2r)-2.5-plo loiifriorilm.s; chromatophoris 

 tat'iiiatis, in t-t'Ilulis juvt-nis dense aggrcgatis, in celhili.s scniorihus 

 numerosi.ssimis et sogregatis ; zoosporangiis ignotis ; gametangiis cylin- 

 drieo-eonit'is, in pediccllis longiorilms brevioribnsve e filamentis repent- 

 ibus nrinndis tcrniinalibns. rard in filamentis longis crcctis terminal- 

 ibns. ()()-! ;i(V longi.s, 18-28^ latis. 



Growing on the sterile base of Gigartina radula f., in company with 

 several other small algae. Cypress Point, Monterey County, Cali- 

 fornia. Type, Gardner, no. 4684 (Herb. Univ. Calif., no. 207046), 

 December. 



This diminutive member of the Melanophyceae is on the border line 

 between Compsonema and Ectocarpus. Our comprehension of these 

 two genera, so far as the vegetative portion is concerned, is that a 

 typical Compsonema, starting from a single cell, develops an extensive, 

 creeping, attaching mass of filaments, radiating in all directions from 

 the origin, which later produces very numerous erect filaments, some 

 of which may remain sterile and others become fructiferous ; and that 

 a typical Ectocarpus, starting likewise from a single cell, develops a 

 rather insignificant series of attaching filaments, more or less rhizoidal 

 in nature, and a relatively extensive system of erect filaments finally 

 producing the fruit. Starting with this conception concerning the 

 two genera, we are assuming that differentiation has proceeded from 

 Compsonema in the direction of the reduction of the creeping portion, 

 to a more extensive development of the erect portion, finally resulting 

 in an Ectocarpus. 



The species under consideration has a relatively extensive system 

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

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

 those from different plants are so intertwined that it is impossible to 

 determine the limits of a distinct individual. In tliis character it 

 resembles an Ectocarpus. The gametangia are like those of a. typical 

 Ectocarpus, 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 creep- 

 ing filaments, we have placed it in the latter genus. 



