MARINE AIvG^E OF BEAUFORT, N. C. 479 



slightly prominent, "nucleus" transversely oval or almost spherical, situated in the 

 medullary layer or in the inner lax part of the cortex, unilaterally attached to the outer 

 cortex, inclosed by a dense, subdiscrete filamentous pericarp with a broad cellular center 

 and radiating, tufted, expanded filaments, on which the carpospores are borne singly 

 at the apices, the center of the "nucleus" joined to the pericarp by single radial strands 

 of sterile filaments, communicating with the exterior by an apical pore. 



Four to five species on Atlantic and Pacific coasts and in Australian regions. 

 Agardhiella tenera (J. Agardh) Schmitz. PI. XCVI. 



Gigartina tenera, J. Agardh, 1841, p. 18. 



Rhabdonia tenera, ]. Agardh, 1851, p. 354. 



Solieria ckordalis, Harvey, 1853, p. 121, pi. 238. 



Rhabdonia tenera, Farlow, i88a, p. 159, pi. 14, f . a. 



Agardhiella tenera, Schmitz, 1889, p. 441 (7). 



Agardhiella tenera, De Toni, 1897, p. 322. 



P. B.-A. Nos. 138 (Rhabdonia tenera) (?), 333 (Agardhiella coulteri) (?), 539. 1396 (?), ai 4 3. 



Frond filiform, 4 to 45 cm. tall, 0.5 to 4 mm. in diameter; decompoundly much branched, branches 

 subalternately virgate, usually going out from all sides, sometimes secund, cylindrical, constricted at 

 the base, gradually tapering toward the apex, bearing numerous linear, fusiform branchlets; tetraspo- 

 rangia scattered through the cortex of unaltered branches zonately divided ; cystocarps borne on sepa- 

 rate plants immersed in slightly swollen branches, rather prominent on one side ; substance when young 

 is very delicate, when older is rather firm; color red to piirple. 



Warm and temperate Atlantic and Pacific coasts of America. 



Abundant in winter and spring, occasional in summer and autumn, 15 to 30 cm. below low water, 

 in harbor and on jetties, Beaufort, N. C., many slender plants dredged from the coral reef, August, 

 1914 and 1915. 



The species varies greatly in habit, some specimens bearing only a few large branches, while others 

 bear many fine small ones. It is not likely to be mistaken for any other species occurring in this region 

 except Eucheuma gelidium; from the latter it is distinguished by its more open habit, with longer, more 

 slender branches, and by its more delicate texture. It here reaches its greatest luxuriance from Decem- 

 ber to June, attaining at that time a height of 30 cm. and fruiting abundantly. Specimens collected 

 during the summer and autumn are often much battered, although an occasional vigorous fruiting plant 

 may be found during this period. 



Yendo ( 1914) has suggested that many American specimens which have been referred to this species 

 should be placed under Rhabdonia robusta (Grev.) J. Ag. As the determination of this point would 

 require more study than it has been possible to give the matter, the author has followed current usage 

 in referring all the plants to A . tenera. This has seemed more proper in that, while some of the plants 

 [notably those dredged from the coral reef in 1914 and 1915 (Plate XCVI, fig. 2), in which the internal 

 filaments were lacking] differed from others in appearance, none of them seemed to agree entirely with 

 the descriptions of R. robutta. 



Borgesen (1919, pp. 361-365) has given a good description, with figures, of the development of 

 the cystocarp of this species. 



Genus 2. Meristotheca Agardh. 



Meristotheca, Agardh, in J. Agardh, 1871, p. 36. 



Frond -flat, more or less richly furcately or pinnately (usually irregularly) divided 

 sometimes proliferous from the margins, usually with numerous warts or papillae arising 

 from the margins and surface; structure cellular-filamentous, hollow, the cavity traversed 

 by numerous filaments, cortex composed of large, rounded cells within, becoming smaller 

 toward the surface, tetrasporangia scattered over the surface among the superficial cells 

 of the cortex, zonately divided ; cystocarps situated in the warts and papillae or embedded 

 in the thallus, more or less prominent, "nucleus" with a filamentous-cellular center and 

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