^ 



156 University of California PuMications in Botany [Vol. 8 



FAMILY 4. BEYOPSIDAOEAE (boey) de-toni 



Thallus a more or less branched, unseptate coenocyte, arising- from 

 rootlike, creeping, often rhizome-like filaments which originate as 

 lowermost branches; branching more or less regularly or irregularly 

 pinnate and lateral pinnules of definite growth arranged pinnately, 

 and either distichous or polystichous, never interwoven ; wall thin, 

 neither incrusted nor provided with trabeculae (as in the Cauler- 

 paceae) ; chromatophores and nuclei numerous and small, the former 

 elliptically discoid and provided with a single pj-renoid each ; vege- 

 tative reproduction by a detachment of pinnules or breaking off of 

 proliferations or the creeping rhizome ; zoospores unknown ; sexual 

 reproduction by 2-ciliated anisogametes produced in gametangia which 

 are slightly modified pinnules {Bryopsis) or ovoid or pyriform out- 

 growths from the pinnules (Pseudohryopsis) ; monoecious or dio- 

 ecious ; female gamete the larger, with large posterior chromatophore, 

 male gamete smaller, brownish-red with reduced chromatophore ; 

 zygote germinating at once. 



Bryopsidaceae De-Toni, Syll. Alg., vol. 1, 1889, p. 427 ; Collins, 

 Green Alg. N. A., 1909, p. 402; West, Algae, vol. 1, 1916, p. 225. 

 Bryopsideae Bory, Voyage Coquille (Duperrey), Bot., 1828, p. 203; 

 Thuret, Rech. sur les zoosp. et les antherid. des Crypt., 1850, p. 217 

 {sub "Bryopsidees"). 



The genus Bryopsis is the only representative of the family 

 Bryopsidaceae on our coast. The family closely resembles the Der- 

 besiaceae, from which it is distinguished by its method of branching 

 and the possession of 2-ciliated, motile, reproductive bodies, the 

 Codiaceae, from which it is distinguished bj^ not having its branches 

 interwoven to form a complex frond, and the Caulerpaceae, from 

 which it is distinguished readily by the thin wall and lack of internal 

 reenforcing plates or trabeculae. The fernlike fronds of our species 

 distinguish them at a glance from all our other filamentous Chloro- 

 phyceae. 



The name Bryopsidaceae, as first used by Bory, included other 

 Siphonales as well as Bryopsis, particularly species of Caulerpa and 

 Vaucheria. The present concept of the family dates from about 

 1850 when Thuret published his classic paper on zoospores and anthe- 

 ridia. 



The account of the reproduction is adopted from Oltmanns (1904, 

 p. 304 et seq.) and has not been verified, as yet, in our species. 



