THE GREEN ALGAE OF NORTH AMERICA 87 



of similar cells, but with only one constriction near base ; simi- 

 lar branching to the fourth order ; zoospores formed in ultimate 

 ramuli, escaping by numerous minute openings. Fig- 27 



Differs from Valonia by the regularly whorled branching, 

 borne on a distinct axis, the presence of annulations, and the 

 absence of lentiform cells. . 



Only one species, E. VERTICILLATA (Kiitz.) Borgesen, 1912, 

 p. 259, figs. 10-12; 1913, p. 66, figs. 51-54. 



Page 374, after description of V. CONFERVOIDES, add, 



6. V. MACROPHYSA Kiitzing, 1843, p. 307 ; 1856, p. 30, PI. 

 LXXXVII, fig. 3; Kuckuck, 1907 /p. 158, figs. 5-10; Borge- 

 sen, 1912, p. 243; 1913, p. 29; V. utricularis Alg. Am.-Bor. 

 Exsicc., No. 171. Cells spherical to pyriform with similar 

 proliferations, solitary or forming more, or less dense masses ; 

 zoospores 4-ciliate. Bermuda, W. I. Europe. 



Often confused with V. utricularis, but in the latter the normal 

 form of the cell is clavate, while in the present species it is 

 short pyriform. In both species, however, there is considerable 

 variation. 



Page 376, for Key to the Species of Struvea, substitute, 



I. Stipe unbranched. 2. 



i. Stipe branched. 3. 



2. Frond 3-5 cm. high, with 4-6 pairs of branches, i. S.anastomosans. 



2. Frond 7-10 cm. high, with 10-15 pairs of branches. 4. S. elegans. 

 3. Each branch of stipe with a separate network. 4. 



3. One network only. 2. S. pulcherrinta. 



4. Branches of stipe opposite. 3. S. ramosa. 



4. Branches of stipe irregular. i. S.anastomosans. 



Page 377, after description of S. RAMOSA, add, 

 4. S. ELEGANS Borgesen, 1912, p. 264, figs. 13-14; 1913, 

 p. 51, figs. 37-38. Stipe cylindrical, 7-10 cm. high, with a few 

 annulations near the base, unbranched, bearing above a single 

 ovate pyramidal network, up to 4 cm. long, of 10-15 P airs f 

 opposite branches, with similar branching to the fourth order. 

 Virgin Islands. 



Resembling .5". anastomosans, but a larger plant, with long 

 simple stipe, and with the branching network ovate acuminate 

 rather than broadly triangular ; the branching is more regularly 

 distichous, and there are several distinct aunulations near the 

 base of the stipe. 5 1 . anastomosans sometimes has one or two 



