32 siphonacej:. 



Fronds 3-6 iuches Iiigli, setaceous, much branched ; normally in a decompound pin- 

 nate manner, but very irregularly so. In what Ave may call typical or normal speci- 

 mens, the outline of the frond is somewhat pyramidal, the lowest branches being very 

 long and patent, the upper gradually shorter and more erect. In such specimens the 

 branches are sometimes simply, sometimes doubly pinnate ; in either case the lower 

 half of the branch or branchlet is bare, the upper plumose, with simple ramuli inserted 

 in nearly distichous order. To describe every variety of ramification different from 

 this, and commonly occurring in this species, would be an endless and useless task ; 

 and worse than useless to found new species on such variations. I have endeavoured 

 above to indicate the principal varieties which I have observed among American spe- 

 cimens. The var. 7 secunda looks very like a distinct species, and had I seen none 

 but carefully selected specimens, possibly I should have so regarded it ; but though 

 many specimens may be found strictly conforming to the character assigned, having 

 all their ramuli secund and recurved, others occur, growing intermixed with them, 

 in which the ordinary ramulification is followed. At Key West I collected some speci- 

 mens which I cannot distinguish from B. rarimlosa, Mont., and which seem to pass 

 through var. 7 and other intermediate forms, into ordinary B. plumosa. Having re- 

 ceived from Dr. Montague himself an authenticated specimen of his plant, I can speak 

 with more confidence. 



Bryopsis plumosa, under one or other of its many forms, is found in most parts of 

 the world, at least within the temperate and tropical zones. In Europe it occurs as 

 far north as the Faroe Islands (lat. 65"). In the Southern Ocean it extends to Cape 

 Horn, and the Falkland Islands, and to New Zealand. The B. Rosa? of the Southern 

 Hemisphere seems to be merely a luxuriant form, and not a distinct species. 



Plate XLV. A. Fig. 1. Bryopsis p/«/noAa, var. 7 secunda ; the natural size. Fig. 

 2 and 3, secund and bilateral plumules from the same ; magnified. Fig. 4. B. plumosa, 

 var. S ranmlosa ; the natural size. Fig. 5, imperfectly iiinnulate branch from the 

 same, magnified. Fig. 6, apex of a branchlet, moi-e highly magnified. 



2. Bryopsis hgpnoides, Lamour. ; frond setaceous, decompoundly much branched > 

 l)ranches spreading to all sides ; ultimate branches filiform, naked below, beset above 

 Avith scattered or crowded, irregularly inserted, very slender, byssoid, pinnated ramuli. 

 Grev. Alg. Brit. p. 180. Harv Phyc. Brit. tab. 119. Wyatt, Alg. Damn. No. 81. 

 Harv. Man. p. 146. (quere Lam. Jour. Bot. 1809- p- 13.5?) B. cupressoides, Lam. 

 fide I. Ag. 



Hab. Key West, W.H.H., Dr. Blodgett, Professor Tuomey. (v. v.) 



Tufts dense, 4-6 inches high. Fronds setaceous, much branched, the branches issu- 

 ing from all sides of a common stem or central filament, long and virgate, either quite 

 simple, or bearing a second set of similar quadrifarious branches. These branches, as 

 in B. piluntosa, though sometimes ramulose nearly to the base, are generally naked in 



