MARINE ALGJB OF BEAUFORT, N. C. 447 



The species considered here seems to be the same as that discussed by B6rgesen (1914), but it may, 

 perhaps, be questioned whether it is the same as Ri-vularia zostera Mohr or Castagnea zosterce Thuret. 

 Both the Beaufort and the Bermuda plants are more branched than the more northern ones called by this 

 name, and seem to belong to a different species. 



The single occurrence of this species on the beach makes it probable that these plants did not grow 

 in this locality, but were brought here from some other region. Since, however, it probably occurs both 

 north and south of this place, it may be expected to establish itself here at any time. 



Genus 3. Leathesia Gray. 

 Leathesia, Gray, 1821, p. 301. 



Frond small, at first globose and solid, at length irregularly lobate and hollow, 

 gelatinous-fleshy; axis short, composed of oblong cells joined into decompound-forked 

 filaments radiating from a central point; peripheral assimilating filaments short, going 

 out from the outermost smaller cells, enwrapped in mucous, simple, clavate, short, 

 moniliform-segmented; longitudinal growth by transverse division of the upper segments 

 of free apical filaments, the upper divisions finally changed into assimilating filaments; 

 "unilocular sporangia" ellipsoid or pear shaped; " plurilocular sporangia" linear, 

 composed of a single longitudinal series of cells; both kinds occurring at the base of 

 peripheral filaments. 



Five to six species, in cold and temperate seas. 

 Leathesia difformis (Linnaeus) Areschoug. PI. LXXXVIII, figs, i and 2. 



Tremella difformis, Lrinnaeus, 1755, P- 429. 

 Leathesia. difformis, Areschoug, 1847, p. 376, pi. 9 B. 

 Leathesia tuberiformis, Harvey, 1852, p. 129. 

 Leathesia difformis, Farlow, 1882, p. 82, pi. 5, f- i. 

 Leathesia difformis, De Toni, 1893, p. 422. 

 P. B.-A. Nos. 130, 829. 



Frond subglobose, variously lobate, variable in size, about i to 5 cm. in diameter, olivaceous brown; 

 at first solid, soon becoming hollow by the disintegration of the cells of the central axis; peripheral 

 filaments clavate, the terminal cell enlarged; sporangia about 35 by 17 mic. 



Cold and temperate North Atlantic and Pacific. 



Abundant on other algae and on rocks of Fort Macon jetties, Beaufort, N. C., April, 1908, March and 

 April, 1909. 



This is the most southern station reported for the species, although it may be found slightly farther 

 south in the winter or spring. The species seems to make a short stay at Beaufort, not being found there 

 in May, 1907, and being collected in only the two months noted during the winter and spring of 1908-9. 

 The Beaufort specimens were small, having a diameter of i to 2 cm. 



Family 5. STILOPHORACE^E (Nwgeli) De Toni and Levi. 



Frond attached by a rootlike disk, filiform, more or less branched, composed of an 

 axial bundle of segmented filaments increasing in length by the division of subterminal 

 cells, and a parenchymatous, few-layered, cortical tissue clothing the axis; this cortical 

 tissue arising from the lower cells of the segmented, subclaviform filaments springing 

 from the axial bundle below its apex; frond solid when young, often becoming hollow^ 

 with age, and traversed by branches of the axial filaments; assimilating filaments present; 

 sporangia of both kinds formed as lateral branches from the base of short, simple, or 

 branched filaments arising from superficial cells; '"unilocular sporangia" obovate or 

 club shaped; "plurilocular sporangia" linear, consisting of a single longitudinal row 

 of cells. 



Five to six species in North Atlantic and Mediterranean. 

 159321 20 6 



