338 TUFTS COLLEGE STUDIES, VOL. II, No. 3 



with numerous short, acute, spine-like ramuli, 25-35 M diarn., of 

 two or three cells each. On rocks exposed to the waves, 

 Florida. So. America. 



Somewhat resembling C. delicatula, but stiffer, branches less 

 erect, and usually more abundant ; ramuli more acute, and not 

 so distinctly secund. 



8. C. NITIDA Kiitzing, 1843, p. 269; C. trichocoma Kiitzing, 

 1854, PI- XXIX,fig. 2 ; Collins, 1901, p. 244. Fronds yellow- 

 ish or whitish green, soft, dense, somewhat mucilaginous, usu- 

 ally up to 10 cm. high, occasionally much more ; main filaments 

 50-100 /A diam., bearing more or less frequent straight, virgate 

 branches, with alternate or secund, rarely opposite, erect 

 branches of higher orders, and secund slender ramuli, 20-30 p. 

 diam.; cells cylindrical, from 4-12 diam. long, usually over 6 

 diam. Jamaica, Bahama. Europe. 



The fronds of this species are soft and slippery, often forming 

 long, skein-like masses, similar to some species of Rhizocloniinn . 

 In the American specimens identified with this species, the fila- 

 ments are more slender than in most European forms. In the 

 north of Europe it seems to be stouter and harsher than with us ; 

 but some Mediterranean forms are soft and nearly as slender 

 as the plants from Jamaica. 



9. C. STIMPSONI Harvey, 18593, p. 333; P. B.-A., No. 

 729. Fronds loosely tufted, up to 30 cm. high, light green, of 

 delicate and silky texture ; filaments 100-150 /u, at base, tapering 

 gradually upward, di- trichotomously divided, branches contin- 

 uously but distantly forking, successively smaller, ultimate 

 branches lateral, secundly pectinate with long ramuli, 20-25 M 

 diam., with rounded or slightly pointed tips. Cells 5-8 diam. 

 long, longest near the base. On shells, etc. Southern Califor- 

 nia. Japan. 



A soft, delicate, silky plant, reminding one of the more 

 slender forms of C. gracilis, but distinct in manner of branching, 

 substance and cell dimensions. 



10. C. LUTEOLA Harvey, 1858, p. Si. Fronds pale yellow- 

 green, tufted, very slender, much branched, not matted ; very 

 flexuous, with rounded angles ; branching irregular, frequently 

 trichotomous ; ramuli secund or opposite, at the tip pecti- 

 nate, somewhat corymbose and crowded ; cells cylindrical, 

 about 60 fj. diam. in main branches, 35 fj. in ramuli, 6-8 diam. 

 long. Key West, Fla., Cuba. 



11. C. FLAVESCENS (Roth) Kiitzing, 1843, p. 267; Harvey, 



