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



The material distributed as P. B.-A., No. 1325, was from a 

 station once connected from the sea, but cut off for several 

 years, the water becoming quite fresh. The Enteromorpha 

 grew in company with species of Oedogonium, Spirogyra, and 

 other fresh water genera, and was as abundant as ever, the only 

 noticeable change being a greater development of the mono- 

 siphonous part in proportion to the rest. 



7. E. ERECTA (L,yng.) J. G. Agardh, 1882, p. 152 ; P. 

 B.-A., No. 461. Frond filiform, with numerous long, usually 

 erect branches, more slender than the main filament ; the ulti- 

 mate ramuli of varying length, polysiphonous, the cells being 

 symmetrically arranged in successive segments, similar to those 

 of Polysiphonia ; cells in the main stem and branches in longi- 

 tudinal and usually in transverse series. Fig. 70. Me. to W. I. 



Europe. 



The most distinctive character of this species is found in the 

 polysiphonous ramuli ; in habit it is not unlike E. crinita, but 

 the cells of E. erecta are usually more symmetrically arranged 

 in the older parts of the frond, and more rectangular. It is not 

 uncommon as a plant of exposed shores. 



8. E. ACANTHOPHORA Kiitzing, 1849, p. 479; 1856, p. 12, 

 PI. XXXIV, fig.. i ; P. B.-A., No. 515. Frond more or less 

 proliferously branched, the branches usually somewhat enlarged 

 upwards, beset with numerous short, spine-like ramuli, with 

 broad base and acute tip ; cells 6-8 /x diam., roundish angular, 

 showing no longitudinal arrangement except indistinctly at the 

 tips of the ramuli ; marine and fresh water. Cal., at shore, and 

 in mountains up to 300 meters. So. America, New Zealand. 



Somewhat resembles E. ramulosa, but the cells are .much 

 smaller, with hardly any indication of longitudinal arrangement ; 

 the substance is less firm, and the color is lighter. The fronds 

 seem to collapse irregularly in drying. The spine-like ramuli 

 vary in abundance, sometimes almost covering the frond ; the 

 regular branches are not very numerous, and seem quite dis- 

 tinct from the ramuli. 



9. E. RAMULOSA (Eng. Bot.) Hooker, 1833, p. 315; Har- 

 vey, 1849-51, PI. CCXL,V ; Ulva clathrata var. ramulosa Far- 

 low, 1881, p. 44. Frond tubular, rather stiff, much branched; 

 branches with short, spine-like ramuli ; cells rather rounded, 

 showing longitudinal series only in the ultimate divisions. 

 Mass, to W. I. Europe, New Zealand, Australia. 



