SUPPLEMENT. 227 



Of this genus several species have been described by authors, all having a close 

 resemblance to each other, and all very variable in ramification. Indeed it is 

 almost impossible to fix characters by which they can be permanently kept apart ; 

 and instead of adding another specific name to the already too numerous list, I 

 prefer to consider the American specimens received as constituting a luxuriant 

 variety of the best known of the established species. All previously recorded 

 species or varieties of these plants are natives of rapid rivers and streams in 

 various parts of Europe. (CfUorVftHMtf, p. 118.) 



HydriiriiN penicillatus, var. oecidentaliN, HARV. 



Frond very long (1-2 feet or more), much branched; branches Tery irregular, scattered or 

 crowded, wormlike, tapering to a fine point, naked or clothed with feathery villous ramuli ; 

 cells ellipsoidal or pear-shaped, twice aa long as their diameter. 



Hub. On the rocky bottom of rivers and streams, in a strong current. Santa Fe, New Mexico, 

 Mr. Fendler, February to April, 1847. (v.s. iu Herb. T.C.D.) 



Fronds attached at base, one or two feet long,' from one to four lines in diameter, very much 

 and irregularly branched ; branches scattered or crowded, simple or divided, a foot or more 

 in length, attenuated to a fine point, sometimes smooth and naked, but generally densely 

 clothed with slender, villons ramenta, spreading to all sides. The gelatinous tubes or sheaths 

 in which the cells are seriated are very obvious, and lie close together in longitudinal, paral- 

 lel strata. The cells are of large size, bright-green color, and variable shape ; some are twice 

 as long as others. 



This I had at first supposed to be a new species, but now regard it as a very 

 gigantic state of //. penicHlattis, Ag., which under various forms and of various 

 si/.es is common in alpine streams in Europe. I fear characters derived from the 

 shape, and size of the cellules are not more to be depended upon than are those 

 taken from the ramification. (ChloroepermecR, p. 118.) 



Draparnaldia opposita, Ao. 



Frond vaguely much branched ; joints of the main filament as long as broad, or shorter ; pencils 

 of ramuli mostly opposite, densely set, lanceolate-acuminate in outline, plumose, bi-tripinnate, 

 the apices much attenuated. Ag. Syst. p. 59. Kutz. Sp. Alg. 357. Lyngb. Hyd. Dan. lab. 

 65, fig. A. Batrachospermum Americanum, Schweinitz. 



ffab. Iu clear streams. New York, Professor Bailey. New Jersey, Mr. Jackson, (v.s.) 



Frond 2-3 inches long, gelatinous, capillary, irregularly much branched ; the branches patent, 

 lateral, more or less divided, and set with lesser ramuli. Main filaments with short articula- 

 tions, as long as their breadth, or shorter, transversely banded. At every two or three nodes 

 and sometimes at every node a pair of opposite penicillato-mnltifid ramuli are thrown off. 

 These are bright green, ovato-lanceolate in outline, much acuminated and twice or thrice pin- 

 nate, their pinnules somewhat constricted at the nodes, and tapering at the apex into long, 

 needle-like, hyaline points. Their cells are commonly nucleated and filled with endochrome. 



Whether this be permanently distinguishable from D. glomerata is doubtful. It 

 has externally the aspect of that species, but its microscopic characters are nearer 

 those of D. plumosa. 



