MARINE ALGJE OF BEAUFORT, N. C. 419 



Thirty species, usually in salt or brackish water, occasionally in fresh water, through- 

 out the world. 



The specific distinctions are founded chiefly on the manner of branching and on the 

 size and arrangement of the cells and are often difficult of determination. 



KEY' TO SPECIES. 



a. Frond flat, the membranes free at the margins, but united between 4. E. lima (p. 420). 



oa. Frond tubular b. 



b. Cells not arranged in longitudinal series except in the very youngest parts 



.'. 3. E. intestinalis (p. 420). 



bb. Cells more or less in longitudinal series, usually in the greater part of the frond c. 



c. Fronds simple, inflated, and flexuous 2. E. flexuosa (p. 419). 



cc. Fronds regularly branched i. E. prolifera (p. 419). 



i. Enteromorpha prolifera (Flora Danica) J. Agardh. 



Viva prolifera. Flora Danica, vol. 5, fasc. 14, p. 7, pi. 763, fig. i, 1833. 

 Enteromorpha prolifera, ]. Agardh, 1882, p. 129, pi. 4, figs. 103-104. 

 Enteromorpha prolifera, De Toni, 1889, p. 122. 

 Enteromorpha prolifera, Collins, 1909, p. 202. 

 P. B.-A. Nos. 470, 610, 913. 



Frond up to several meters long and 2 cm. in diameter, tubular or compressed, with more or less 

 abundant branches which are usually simple, but sometimes also proliferous; branches varying much in 

 length and diameter; cells 10 to 12 mic., in the younger parts always arranged in longitudinal series, 

 which become less distinct in the older parts; membrane 15 to 18 mic. thick, not much exceeding the 

 dimensions of the cells in cross section. 



Greenland to West Indies; Alaska to California; Europe. 



Beaufort, N. C.: Abundant throughout winter 1908-1909; very abundant May, 1907, and April, 

 1908, on rocks, shells, and piers throughout harbor and at Fort Macon and Shackleford, extending from 

 about 10 cm. below low water to high- water line; very abundant at water line on sea buoy and channel 

 buoy at entrance to Beaufort Harbor, July, 1909; abundant on rocks and sand breaks at Shackleford and 

 Fort Macon between tide lines throughout summer (?). Cape Lookout beach, very abundant on old 

 wreck about 20 m. from water at low tide, August, 1906. Pamlico Sound, Ocracoke, N. C., fairly 

 abundant on posts of beacon between tide lines (?). Southport, N. C., very abundant on wall and 

 shore, August, 1909. Georgetown, S. C., very abundant on jetty and shells on beach. Pawleys Island, 

 near Georgetown, S. C., abundant on shells in bay near inlet. Port Royal, S. C., fairly abundant on 

 buoy at water line. 



This seems to be the only species of Enteromorpha occurring in this region throughout the year. 

 Specimens collected in December are 3 to 4 cm. long, densely matted with many upright, filiform or 

 club-shaped branches; in April and May this species is, next to Ulva lactuca, the most abundant in the 

 harbor; the specimens at this time are 3 to 45 cm. long; in summer, material apparently belonging to this 

 species is found as small, stunted tufts, i to 2 cm. long, on rocks and sand breaks near the inlet, this condi- 

 tion.continuing as late as October or November. With the exception of these stunted representatives 

 and of specimens occasionally growing on buoys, etc., this species has not been found here during the 

 summer or autumn. 



In habit this species is very variable, from slender, slightly branched forms, only a few centimeters 

 long, to rich and repeatedly branched fronds; delicate or coarse; branches sometimes long and slender, 

 sometimes short and very densely set, sometimes long and short intermingled quite without order. It 

 also occurs in fresh water and about salt springs. 



a. Enteromorpha flexuosa (Wulfen) J. Agardh. 



Conferva flexuosa, Wulfen. in Roth, 1800, p. 188. 



Enteromorpha flexuosa, J. Agardh, 1882, p. 126. 



Enteromorpha flexuosa, De Toni, 1889, p. 121. 



Enteromorpha flexuosa, Collins, 1909, p. 203. 



P. B.-A. Nos. 462, 2004. 



Frond cylindrical, tubular, simple, tapering to a filiform stipe below, above inflated, flexuous, and 

 intestinelike; cells 6 to 8 by 8 to 12 mic., roundish polygonal, in longitudinal series; membrane somewhat 

 thickened on the inside; chromatophore filling the thick- walled cell. 



