THE GREEN ALGAE OF NORTH AMERICA 405 



rather sparingly branched, often undulately curved and swollen 

 in places ; ramuli rather short, blunt, in secund series of a few 

 each, the rachis naked between the series. W. I. 



So. America. 



The four species, B. foliosa, B. pennata, B. Lepricurii and 

 B. Harvcyana are certainly closely related ; only continued 

 stiuty of the living plants will settle the question of their dis- 

 tinctness. That the three last named are kept separate here is 

 chiefly due to their being so kept by Miss Vickers, who studied 

 and collected them at Barbados. 



7. B. PENNATA L,amouroux, 1809, p. 134, PI. Ill, fig. i ; 

 Vickers, 1908, p. 30, PI. LJI ; B. pennatula J. G. Agardh, 

 1848, p. 6. Fronds seldom over 5 cm. high, tufted, simple or 

 nearly, so, bearing, except at the very base, rathtL- short, 

 densely set, distichous ramuli of uniform length, giving a linear 

 outline to the frond. W. I., Mexico. 



The narrow subsimple frond reminds one of the European B '. 

 my ura ; but the distichous ramuli place it near B. plumosa. 



8. B. HARVEYANA J. G. Agardh, 1886, p. 22 ; Vickers, 

 1908, p. 29, PI. lyl ; P. B.-A., No. 1532 ; B. plumosa var. scatnda 

 Harvey, 1858, p. 31, PI. XL,V.A, figs. 1-3. Fronds up to 15 

 cm. high, dark green, growing in dense tufts ; main stems mod- 

 erately and ratherirregularly branched, branches bearing near 

 the end rather short, distichous ramuli, the general outline be- 

 ing linear-lanceolate, or linear with rounded ends, the tip of 

 the branch somewhat prolonged. This tip is usually somewhat 

 incurved, and the ramuli on both edges of the rachis turn in- 

 wards towards one side of the latter, so that unless closely ex- 

 amined they appear secund. Fla., W. I. 



The characters by which this is distinguished from B. plu- 

 mosa are not as sharp nor as constant as might be wished ; but 

 well developed plants seem quite distinct by their densely tufted, 

 little branched fronds, each filament with scorpioidal-appearing 

 tip. 



9. B. FOI^IOSA Sender, 1845, p. 49. Frond 2-3 cm. high, 

 ascending from more or less abundant creeping filaments ; usu- 

 ally simple, occasionally once or twice forked, tip somewhat 

 incurved, base naked, but with scars of fallen ramuli ; upper 

 part thickly set with ramuli, arising dichotomously on the 

 rachis, but curving immediately, and all turned in the same di- 

 rection, so as to appear secund on the outer, convex, side of the 

 rachis ; ramuli slender, patent, the lowest longest, up to 5 mm., 



