THE GREEN AL,GAE OF NORTH AMERICA 413 



Forma DISTICHA Weber, 1898, p. 270. Ramuli patent, not 

 closely set, in distichous, opposite series on the rachis. St. 

 Croix. 



Forma TOMENTELLA (Harv.) Weber, 1898^.270; Vickers, 

 1908, p. 26, PL XXXIX. Frond more prostrate than in the 

 type, surrounded by very densely set, spreading ramuli ; ramuli 

 in the prostrate part of the frond often prolonged into extended 

 filaments. Barbados. Pacific. 



5. C. PROLIFERA (Fb'rsk.) Lamouroux, iSoga, p. 30; Har- 

 vey, 1858, p. 16, PI. XXXVIII. B; Weber, 1898, p.' 278, PI. 

 XXII, fig. i ; P. B.-A., No. 269. Stolon usually stout, naked, 

 frond plane, linear, obtuse, up to 30 cm. long by 3 cm. wide, 

 rarely divided, margin entire, sometimes slightly undulate ; 

 similar fronds often arising proliferously from any point on the 

 original frond ; color blackish or olive green. Lateral to 40 in. 

 depth. Fig. 160. N. C. to Fla.; W. I., Yucatan. Mediterranean. 



Forma OBOVATA J. G. Agardh, 1872, p. n ; Borgesen, 1907, 

 P- 359. fig- 4- Frond shorter and broader, obovate-oblong ; 

 same localities as the type. 



Forma ZOSTERIFOLIA Borgesen, 1907, p. 359, fig. 6. Fronds 

 narrow-lanceolate, interrupted and abundantly proliferous. In 

 shallow water. St. Croix. 



Easily distinguished from all our other species by the flat 

 frond, linear to rounded ; growing in sandy places at low water 

 mark and in deeper water. 



6. C. CRASSIFOLIA (Ag.) J. G. Agardh, 1872, p. 13 ; C. pin- 

 nata Weber, 1898, p. 289, PL XXIV, figs. 1-4. Stolon creep- 

 ing, naked ; frond borne on a cylindrical or flattened pedicel, 

 plane, linear-lanceolate, pinnate, up to 10 cm. high ; pinnules 

 opposite, plane, at the base as wide or almost as wide as at the 

 middle, erect or patent, tip rounded or mucronate. Literal to 

 30 m. depth. 



Forma TYPICA (Weber) Borgesen, 1907, p. 363. Pinnules 

 erect, sublinear, not contracted at the base, often acuminate. 

 Fla. from Palm Beach south ; W. I. Tropical seas generally . 



Forma MEXICAN A (Sond.) J. G. Agardh, 1872, p. 13, (as 

 variety); Vickers, 1908, p. 26, PL XL,; P. B.-A., No. 80; C. 

 mexicana Harvey, 1858, p. 16, PL XXXVII. A. Pinnules 

 erect, slightly contracted at the base, often enlarged at the sum- 

 mit, ending sharply in a mucro ; sinus between the pinnules 

 rounded. Same distribution as the type. 



Forma laxior (Weber) nov. comb.; C. pinnata forma hixior 

 Weber, 1898, p. 291 ; C. crassifolia var. mexicana Alg. Am.- 



