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



The largest species of the North Atlantic coast, not to be mis- 

 taken for any other species occurring there. It has been re- 

 ported from few localities,. but is likely to be found at various 

 points south of Cape Cod, and on the west coast south of 

 Vancouver. 



Var. DISTANS (Ag.) Kiitzing, 1849, p. 392 ; C. diffusa Harve}*, 

 1846-51, PI. CXXX; 1858, p. 83; Conferva diffusa Wyatt, 

 Alg. Damn., No. 144. Main branches long, nearly bare of sec- 

 ondary branches ; cells longer than in the type ; nodes not con- 

 stricted. Mass, to New Jersey. Europe. 



Connected with the type by intermediate forms. 



29. C. RUPESTRIS (Iy.) Kiitzing, 1843, p. 270; Harvey, 

 1846-51, PI. CLXXX ; 1858, p. 74; Farlow, rSSi, p. 51; 

 P. B.-A., No. 728. Fronds densely tufted, dark green; fila- 

 ments stiff, 150 p. diam. at the base, 70-80 ^ in the rarnuli ; cells 

 3-4 diam. long ; branches opposite or in whorls of four, erect ; 

 ramuli short, blunt or subulate. Greenland to Gay Head, 

 Mass. Europe. 



A distinct species, growing usually on rocks in the literal 

 zone, especially in places covered by Fuel and other large 

 algae ; when growing it is a rich dark green, but in drying the 

 color becomes duller and the plant seems coarse : it seems to be 

 in as good condition in winter as in summer, while most North- 

 ern species of Cladophora are spring and summer plants. 



30. C. OVOIDEA Kiitzing, 1843, p. 266; 1853, PI. XCII, 

 fig. i. Fronds 5-15 cm. high, stiff, rather dull green ; filaments 

 distantly dichotomous, 150-200 /x diam. below, branches becom- 

 ing more lateral and secund above ; upper ramuli not over 60 p 

 diam , tips rounded or slightly pointed ; cells in lower part 

 cylindrical, 4-8 diam. long; above ovoid, 1^2-3 diam. long. 

 Santa Cruz, Cal. and vicinity. Europe. 



This plant is often found in collections bearing the name of C. 

 cartilaginca ; but that species is probably a Spongomorpha. 



31. C. UTRICULOSA Kiitzing, 1843, p. 269 ; 1853, PI. XCIV, 

 fig. i ; Wittr. and Nordst., Alg. Exsicc., No. 929. Fronds 

 tufted, light or dull green, 10-20 cm. high ; filaments firm, sub- 

 membranaceous, di- polychotomous, 100-250 p. diam. near base, 

 in upper part set with lateral, often secund ramuli, 70-100 /u. 

 diam. ; cells 6-8 diam. long below, 2-4 diam. above. Jamaica, 

 Bahama, Porto Rico., etc. Europe, So. America. 



A species varying much in size, extent of branching, etc. 



