1920] Setchell-Gardner : Phycological Contributians 287 



Ulva taeniata has been found thus far on the coast of central 

 California only, while TJ. dactylifera has been found only on that of 

 southern California. The differences between the two have been 

 enumerated under the latter species. From U. fasciata f. costata 

 Howe it differs particularly in its basal portion. Ulva fasciata Delile 

 seems to be a species nearly if not absolutely plane, while U. taeniata 

 is always crisply ruffled. No. 862 of the Phycotheca Boreali- Americana 

 represents this species very well. 



Prasiola 



There are eight species of Prasiola at present accredited to the 

 territory of the Pacific Coast of North America. One of these, 

 Prasiola crispa (Lightf.) Menegh., is, we believe, strictly terrestrial, 

 at least so far as our territory is concerned. Another, P. calophylla 

 (Carmich.) Menegh., is also terrestrial, but found with us in a marine 

 locality. Three species, P. horealis Reed, P. meridionalis sp. nov., and 

 P. delicota sp. nov., are strictly marine. One species, P. Gardneri 

 Collins, has been removed to the genus Merismopedia (M. Gardneri 

 Setehell), while three species, P. fluviatilis (Sommerf.) Aresch., P. 

 mexicana J. Ag., and P. nevadensis sp. nov., are inhabitants of cold 

 fresh-water streams. 



Prasiola mexicana J. Ag. (1847, p. 6) is based upon specimens 

 collected in Mexico by Professor Liebmann of Copenhagen. The type 

 locality is Santa Maria Alpatlachna in Mexico. The habitat is 

 turbulent mountain streams. The habit is that of a broad plant, 

 umbilicate at the base and laciniate and irregularly crispate. Agardh 

 simply adds that the areolae are regularly quaternate. No mention 

 is made of the presence of intercellular lines, "viae inter stitiales," in 

 this first description. Jessen (1848, pp. 19, 20, pi. 1, figs. 17-20) gave 

 a more ample description and illustrations from materials and infor- 

 mation provided by Liebmann. Lagerstedt (1869, p. 26) redeseribed 

 the species, but drew his information largely, if not entirely, from 

 Bolivian specimens. J. G. Agardh (1882, p. 84) added nothing in his 

 final review of the genus Prasiola. 



Thus far the specimens from our mountain streams have all been 

 referred to Prasiola mexicana J. Ag. (1847, p. 6), a species with broad 

 fronds, umbilicate or nearly so at the base, and arising from a disk, 

 possibly later developing secondary rhizoidal outgrowths of attach- 

 ment on the decumbent base. The color is dark green and the laciniae 



