V. GELIDIACE.E. 123 



The fronds in all the species are much branched, and generally densely tufted 

 sometimes formed into cushion-lilvc or mossy mats, whence the generic name, 

 derived from Hypnum, a well known genus of mosses. The branches are frequently 

 virgate, clothed throughout with awl-shaped, spreading or divaricated ramuli ; but 

 there is much difference in ramification between the sterile and fertile fronds of the 

 same species, which makes the determination of these plants often a matter of no 

 small difficulty. 



In arranging the American species, I gladly adopt the views of Prof. J. Agardh, 

 who in his recent admirable work (Sp. Gen. et Orel. Algaru77i, vol. 2, p. 438-455) 

 has revised the genus, casting out Algai which had been erroneously placed in it, 

 and establishing the true congeners on a more certain basis. And I may take this 

 opportunity of confessing that I have myself been guilty in this matter, having 

 formerly associated with Hypnea, Cystoclonium purpurascens, a plant of very opposite 

 affinities. 



Section 1. Virgate. Sterile fronds tufted, with virgate branches clothed with 

 subulate ramuli, the older ramuli constricted at the base ; tetrasporiferous fronds 

 similar, having tetraspores immersed in pod-shaped ramuli ; conceptacuUferous 

 fronds divaricately much branched. 



1. Hypnea musciformis., Lamour. ; fronds tufted, virgately branched ; branches 

 filiform, in the lower part clothed on all sides with subulate ramuli, incrassatedand 

 somewhat naked below the apex, which is often strongly hooked inwards ; mature 

 ramuli tapering to both ends ; those bearing tetraspores incrassated and pod-like in 

 the middle ; those with conceptacles spinescent, divaricately branched. /. Ag. Sp. 

 Alg. 2, p. 442. Kiitz. Sp. A/g. p. 758. Hypnophycus musciformis, Kiitz. Phyc. t. 60, 

 Jig. 4. Fiicus musciformis, Wulf. — Turn. Hist. 1. 127. Esper^ t. 93. 



Hab. New Bedford, Massachussetts, Dr. M. B. Roche. Sullivan's Island, South 

 Carolina, Prof. Gibbes, W. H. H. Anastasia Island, Dr. Durkee. Key "West, Mr. 

 Binney, W. H. H., Dr. Blodgett (17), Prof. Tuomey (19). Pine Islands and Key 

 Biscayne, Prof. Tuomey (8, 11, 32). Pacific Coast, at Nootka Sound, i/r. Menzies^ 



1787. (v. v.) 



Fronds densely tufted, four to eight inches long, as thick as sparrow's quill below, 

 attenuated upwards, irregularly decompound, generally with an evident stem set 

 with copious, lateral, virgate branches, the lowest of which are the longest, and 

 most of them, as well as many of the secondary branches, incrassated toward the 

 apex and strongly hooked or revolute, sometimes circinate. Branches once or twice 

 compound, for three-fourths of their length furnished on all sides with very slender 

 subulate ramuli, one to three lines long, as thick as hog's bristle, acute, at length 

 constricted at the base, patent, densely or laxly set, gradually fewer toward the 

 ends of the branches, where, especially in the incrassated and hooked extremities, 

 they are secund along the outer side of the branch. In some specimens these 



2 K 



