V. RHODOMELACE.E. 37 



mark. My specimen of P. physarthra, Kiitz. is very imperfect, but it scarcely seems 

 specifically dilFerent from P. breviariiadata, as here understood. 



Plate XYI. B. Fig. 1. Tuft of Polysiphonia breviartlcidata ; the nahiral size. 

 Fig. 2, portion of a secondary branch, with its slender multifid tertiary ; fig. 3, apex 

 of a branch, with conceptacle ; fig. 4, apex in which tetraspores are imbedded ; 

 fig, 5, base of the stem, to show the manner of rooting ; fig. 6, roots ; fig. 7, trans- 

 verse section of the stem : all the latter figures more or less highly magmfied. 



7. Polysiphonia Binnei/i, Haw. ; filaments rather rigid, setaceous, alternately 

 decompound, much branched ; branches elongate, spreading, of unequal length, 

 twice, thrice, or oftener compounded, and at length resolved into capilkiry, multifid 

 ramuli ; nodes swollen, pellucid ; internodes four-tubed ; those of the stem and 

 branches once and half or twice as long as broad, of the ramuli shorter than their 

 breadth ; tetraspore of small size, subsolitary in distorted terminal ramuli. A stem 

 and brandies plentifully beset (as if proliferously) with slender, simple, or multifid 

 capillary, lateral ramuli. 



Hab. Key West, W. H. H. /3. at Key West, Mr. Binney! Prof. Tmmey, (3) 

 W. H. H. Apalachicola, Mr. Loundshury. (v. v.) 



Frond 2-4 inches high, as thick as hog's bristle, with an ovate outline in the 

 spread of the branches. Stem subsimple, closely set throughout with lateral 

 spreading branches, the lowest of which are long, the rest gradually shorter. 

 These primary branches are either subsimple, or twice or thrice alternately decom- 

 pound, each series of lesser branches gradually more slender, till the frond is 

 resolved into capillary ramuli. In /3. both stem and branches emit on all sides 

 lateral, simple and hair-like, or multifid ramuli, half an inch long, much more 

 slender than the internodes from which they spring, very irregularly placed, often 

 much crowded, and often laxly scattered. The nodes of the stem and branches are 

 swollen ; they are pellucid to the very base of the frond. Internodes of the main 

 divisions at least once and half as long as broad, but generally rather more ; those 

 of the younger parts uniformly short. Tidjes four, very broad. Colour a deep 

 brown. Substance very tough, long resisting the action of fresh water. It very 

 imperfectly adheres to paper in drying. 



Our var. y9. has a rather different aspect, owing to the profusion of lateral ramuli. 

 It seems, however, to be analogous to similarly prolifoi'ous states of various CV/'a//(/a, 

 &c. 



This species is nearly allied to P. breviartkidata, but is a more slender plant, with 

 more compound and patent branches, and the internodes of all the principal divi- 

 sions are uniformly of greater length. In ramification it more nearly resembles 

 P. Olneyi, which has however a totally different substance. 



