MARINE ALG^E OF BEAUFORT, N. C. 425 



The material from Beaufort is finer and less rigid than most specimens of this species from other 

 localities, approaching in this respect C. linum, but is coarser and more rigid than most specimens of the 

 latter species. The comparative width of the filaments is as follows: C. melagonium, 180 to 440 mic.; 

 C. linum, 142 to 434 mic.; C. melagonium (Beaufort specimens), 120 to 240 mic. Both of the former 

 have length of cells from slightly less than i to more than 2 diameters, the Beaufort specimens have 

 length of cells from two-thirds to 2 diameters, the majority of cells being i diameter or less. In spite 

 of these variations, there seems little doubt that the material from Beaufort belongs to this species, 

 forma rupincola. It is easily distinguished from C. linum at Beaufort by its coarse, rigid, dark-green 

 filaments. 



It has been found at this place only in May, 1907, not being observed in April, 1908. This is a 

 northern species, and the present locality is the most southern station reported for it. It is not improb- 

 able that this is its southern limit, although it may be found farther south in the winter or spring. 



I 

 2. Chaetomorpha linum (Mueller) Kuetzing. 



Conferva linum, Mueller, in Flora Danica, torn. 5, p. 4, pi. 771, f. 2, 1788. 



Chaetomorpha linum, Kuetzing, 18433, p. 204. 



Chaetomorpha sutoria, Harvey, 1838, p. 87. 



Chaetomorpha longiarticulata, Harvey, 1858, p. 86, pi. 46, E- 



Chaetomorpha olneyi, Harvey, 1838, p. 86, pi. 46, D. 



Chaetomorpha linum, Farlow, 1882, p. 47. 



Chaetomorpha linum, De Toni, 1889. p. 269. 



Chaetomorpha aerea 1. linum, Collins, 1909, p. 325. 



Chaetomorpha linum, Collins, 1918, p. 79. 



A. A. B. Ex. No. 175. 



P. B.-A. Nos. 22, 1863 (C. aerea f. linum). 



Filaments unattached, prostrate, light green, rather stiff, diameter 200 to 250 mic., cells about as 

 long as broad. 



Nova Scotia to West Indies; warm and temperate waters generally. 



Rather rare, shoal south of laboratory, Beaufort, N. C., August, 1903 (?); marsh west of laboratory, 

 August, 1907 (?). 



This species apparently bears the same relation to C. linum f . aerea as the loose form of C. melagonium 

 does to the attached form. It occurs in great masses of curled and crisped filaments in warm, shallow 

 bays. 



The Beaufort material probably belongs to this species, but was not found in sufficient quantity for 

 a positive determination. 



Forma aerea (Dillwyn) Collins. Fig. 2A. 



Conferva aerea, Dillwyn, 1809, pi. 80. 

 Chaetomorpha aerea, Kuetzing, 18493, p. 379. 

 Chaetomorpha aerea, Harvey, 1858, p. 86. 

 Chaetomorpha aerea, Farlow, 1882, p. 46. 

 Chaetomorpha aerea, De Toni, 1889, p. 272. 

 Chaetomorpha aerea, Collins, 1909, p. 324, pi. 12, f. 115. 

 Chaetomorpha linum f . aerea, Collins, 1918, p. 79. 

 P. B.-A. Nos. 76, 1526 (C. aerea). 



Filaments attached, erect, yellowish green, 125 to 400 mic. or less in diameter, cells about as long as 

 broad, base of filament usually more slender than the upper part; when producing zoospores the fertile 

 cells are much inflated and nearly globular. 



Maine to West Indies; California; warm and temperate waters generally. 



Sometimes abundant on rocks between jetties at Fort Macon, summer and autumn, forming flaccid, 

 tangled masses of filaments about 6 dm. above low water, and fairly abundant on sea buoy, September, 

 1905, Beaufort, N. C. Abundant on rocks in tide pool, Morris Island, 10 cm. above to 10 cm. below 

 water level, water warm to touch, Charleston, S. C. 



In habit like C. melagonium, but of somewhat smaller diameter, lighter color and softer texture; 

 not firm enough to stand erect when taken from the water. 



Of varying degrees of coarseness. The Beaufort material is finer than specimens from other locali- 

 ties, being 80 to no mic. wide, with cells 90 to 225 mic. long. In characters other than the size of the 

 filaments, this material seems to agree with "C. aerea," as observed in herbaria, and is certainly more 



