254 University of California Puhlications in Botany [Vol.8 



restricted point of view rather than the more ample conception. The 

 form names appended to the species, as given above, are simply for 

 the purpose of giving some idea of the amplitude of variation of the 

 species even as most narrowly delimited. 



6. Enteromorpha acanthophora Kuetz. 



Frond more or less proliferously branched, the branches usually 

 constricted at the base, beset with numerous short, spinelike ramuli, 

 with somewhat narrowed base and acute tip ; cells 11-13/x diam., 

 angular, showing no longitudinal arrangement except indistinctly at 

 the tips of the ramuli and in the spinelike branchlets. 



Guaymas, Mexico. 



Kuetzing, Sp. Alg., 1849, p. 479, Tab. Phyc, vol. 6, 1856, pi. 34, 

 f. 1; Collins, Green Alg. N. A., 1909, p. 200 (in part). 



The figure and description of Kuetzing (1849, p. 479 and 1856, 

 pi. 34, f. 1) provide our chief knowledge of this species, the type 

 specimens of which are from New Zealand. "We have not seen the 

 type but have studied New Zealand specimens which seem to belong 

 here. We are encouraged to refer to this species, although doubtfully, 

 specimens collected by T. S. Brandegee at Guaymas, Mexico, which 

 have a general resemblance to Enteromorpha intestinalis, but which 

 are beset with short, spinelike branches. We do not think that no. 515 

 of the Phj'cotheca Boreali- Americana, a plant of fresh water, is prop- 

 erly to be referred to E. acanthophora. Its membrane is too thin 

 (about 13/A, instead of 30-45ju,) and its cells (4-5/a diam., instead of 

 10-13/a) and cross section, as well as its branching more closely, 

 resemble those of E. micrococca f. suhsalsa, although not strictly in 

 agreement with them. 



7. Enteromorpha prolifera (Muell.) J. Ag. 



Frond up to several meters long and 2 cm. diam., tubular or com- 

 pressed, with more or less abundant proliferous branches, which are 

 usually simple, but sometimes also proliferous ; branches varying much 

 in length and diameter; cells 10-12ju, in diameter, in the younger parts 

 always arranged in longitudinal series, which become somewhat less 

 distinct in the older parts ; membrane 15-18/a thick, not much exceed- 

 ing the dimensions of the cells in cross section. 



