1925] Setchell-Gardner: Melanophyceae 497 



2. Ralfsia californica S. and G. 



Plate 36, fig. 22 



Thallus flattened, crustaceous, circular to irregular in outline, 

 adhering firmly without rhizoids to the substratum by the whole lower 

 surface, 280-350/x thick, 2-4 cm. diam., dark brown in color ; basal 

 parenchymatous layer composed of 8-12 layers of cells in vertical rows; 

 zoosporang'ia numerous, clavate, borne laterally at the base of the 

 paraphyses, distributed uniformly over the central and larger part 

 of the frond, 80-95yii (up to 14(V) long, 16-22/x (up to 32/x) thick; 

 gametangia unknown; paraphyses cylindrical to slightly clavate, 

 180-220ju, long, 9-llja broad at the outer end ; hairs unknown. 



Usually found growing on smooth, flattened pebbles and on rock 

 ledges in the upper sublittoral belt, and in tide pools in the littoral belt. 

 Central California. 



Setchell and Gardner, Phyc. Cont., VTI, 1924, p. 2. 



Ralfsia californica is very similar and is probably closely related to 

 R. clavata (Carm. ) Crouan and has passed under that name locally 

 for some time. Careful comparison, however, with material of that 

 species from the Atlantic coasts of America and Europe shows several 

 differences in detail, sufficient to entitle it to specific rank. The speci- 

 ments are, in general, much larger in diameter and are thicker. The 

 paraphyses are generally longer and narrower. The zoosporangia are 

 longer and relatively narrow. The cells of the basal portion are 

 slightly smaller, 



3. Ralfsia verrucosa (Aresch.) J. Ag. 



Frond coriaceous, adhering firmly throughout to the substratum, 

 juvenile state circular in outline, becoming more or less distorted, 

 especially on coming in contact with each other and with other crus- 

 taceous algae, 3-12 cm. diam., 1-2 mm. thick, with concentric zones 

 and radiating lines ; color olive brown ; erect vegetative filaments 

 curved towards the zone of active growth; paraphj'-ses up to 130/x 

 high, composed of 6-9 cells, the lower 2-3 times as long as broad ; 

 zoosporangia ovoid to pyriform, 65-80ja long, 15-25/^ broad ; game- 

 tangia short, terminal ; both reproductive organs on the same indi- 

 vidual, disposed in sori. 



