MARINE ALGA! 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. Pl. XCVI. 
Gigartina tenera, J. Agardh, 1841, p. 18. 
Rhabdonia tenera, J. Agardh, 1851, p. 354. 
Solieria chordalis, Harvey, 1853, p. 121, pl. 23a. 
Rhabdonia tenera, Farlow, 1882, p. 159, pl. 14, f. a. 
Agardhiella tenera, Schmitz, 1889, p. 441 (7). 
Agardhiella tencra, De Toni, 1897, p. 322. 
P. B.-A. Nos. 138 (Rhabdonia tenera) (?), 333 (Agardhiella coulteri) (?), 539, 1396 (?), 2143. 
Frond filiform, 4 to 45 cm. tall, o.5 to 4mm. 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- 
trangia scattered through the cortex of unaltered branches zonately divided; cystocarps bome 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 purple. 
Warm and temperate Atlantic and Pacific coasts of America. 
Abundant in winter and spring, occasional in summer and autumn, rs 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 Euchewma 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. robusta. 
Bérgesen (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 papille 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 
