MARINE ALGJE OF BEAUFORT, N. C. 475 



these fertile filamentous branches confluent into an hymenium on the apices of which 

 the carpospores are borne singly or, rarely, in short chains. 



About 90 species, all marine, mostly in warm and temperate seas. 



Genus Gelid him Lamouroux. 

 Gelidium, Lamouroux, 1813, p. 40. 



Frond terete or flattened, pinnately decompound, of tough, firm texture, with thick 

 dense rind; central axis composed of a segmented, longitudinal filament, from which 

 arise numerous obliquely longitudinal filaments verticillately arranged and densely 

 coalescent into a proper cortex, outer rind cellular, with larger cells toward the center, 

 smaller ones toward the periphery ; central axis with distinct apical cell. Tetrasporangia 

 formed in sori immersed in local swellings on both sides of the thallus below the apices 

 of ordinary pinnae, rotund, cruciately divided; cystocarps immersed in swollen portions 

 below the apices of ordinary pinnae, usually divided by a longitudinal partition into two 

 chambers, one on each side of the flattened thallus, each chamber communicating with 

 the exterior by a separate pore, carpospores obovate arising singly from the hymenial layer, 

 pericarp raised up from the hymenial layer but joined with it by numerous simple fila- 

 ments, antheridia occurring in superficial patches; tetrasporangia and cystocarps occur- 

 ring on separate plants. 



About 25 species recognized, many separated by inconspicuous, probably doubtful, 

 characters; in warm and temperate seas. 



KEY TO SPECIES. 



Upright branches i to 2 cm. tall or less, comparatively thick, flattened, much branched 



i. G. coerulescens (p. 475). 



Upright branches 2 to 3.5 cm. tall, slender, subterete, sparsely branched 2. G. crinale (p. 475). 



i. Gelidium coerulescens Kuetzing. PI. XCV, fig. i. 



Gelidium c&rulescens, Kuetzing, 1868, Bd. 18, p. 19, pi. 56, f. z. 



Thallus erect, flattened, arising from a fine, filiform, creeping base, i to a cm. tall, 0.3 to 0.5 mm. 

 wide in widest portion; branching decompound, distichous from the margins, sparse below, more or 

 less dense above; texture fleshy gelatinous; color, dark purplish brown. 



West Indies; New Caledonia. 



Very abundant, forming low, dense masses on jetties, walls, shells, and stones at Fort Macon, 

 Beaufort, N. C., and along town front from about 10 to 70 cm. above low tide line, April to October, 

 probably throughout the year. 



This species was identified by Mr. Collins on the basis of a Guadeloupe specimen determined by 

 Crouan, and it may perhaps be questioned whether it is really the species described by Kuetzing.. 



a. Gelidium crinale (Turner) J. Agardh. PI. XCV, fig. 2. 



Fucus crinalis. Turner, 1808, pi. 198. 

 Gelidium crinale, J. Agardh, 1876, p. 546. 

 Gelidium crinale, Farlow, 1882, p. 158. 

 Gelidium crinale, De Toni, 1897. P- 146. 

 P. B.-A. Nos. 195, 2089. 



Primary frond decumbent, about 0.5 mm. in diameter, giving off erect branches, terete or some- 

 times slightly flattened, slender, 2 to 7 cm. tall, sparingly branched, sometimes almost simple; color 

 purple or yellowish brown. 



Warm and temperate waters generally, occurring on our coast from Maine to Florida. 



Fairly abundant between tide lines on Fort Macon jetties, Beaufort, N. C., April to August, 1908, 

 probably occurs throughout the year, abundant on submerged shells in Newport River near "Green 

 Rock, " August, 1906; abundant in Core Sound near Leckly 's Island July, 1908; fairly abundant in Pam- 

 lico Sound on shells and posts between tide lines, Ocracoke, N. C., August, 1907; one specimen on 

 submerged shell, Pawleys Island, near Georgetown, S. C., August, 1909. 



