FRESn-WATER A L G .E F T II E U x\ 1 T E D S T A T E S. 69 



blackish-green layer, which it makes upon the bark is very peculiar, being almost 

 membranaceous, and especially in the dried state, presenting a rough, somewhat 

 warty surface. The trichomata have the sheath more distinctly in the form of a 

 hollow cylinder, or, in other words, more plainly a sheath, than any other species 

 T have seen of the genus ; the cells are also without any apparent walls, and are 

 placed very closely together, so that the whole filament looks very like a scylo- 

 nema. 



Fig. 1, pi. 9, represents a portion of a frond magnified 260 diameters. 



S. pelliicidulu!^, Wood. 



S. immersus; trichomatibus ramossissimis, soJitariis vel subsolitariis ; ramis plerumque unila- 

 teralibus, ramnlosis; ramulorum apicibus late rotundatis, baud attenuatis; cellulis in serie- 

 bus simplicibus dispositis, in tricbomatibus nonnihil rotundatis, in raraulis sspe angularibus, 

 plerumqne compressis, diametro ffiqualibus — 4 plo brevioribus ; termiualilms cylindrieis et 

 obscure articulatis ; cellulis interstitialibus nullis; vaginis arctis, hyalinis, baud lamellosis; 

 cytioplasmate aerugineo vel brunneo, minute granulato. 



Dfawi.— Tricb. cum vag. 7/55" = .00106" ; sine vag. = .0008". 



Syn. — S. jxllucidulus, Wood, Prodromus, Proc. Amer. Pbilos. Soc, 1869, p. 133. 



Hah. — In stagnis, prope Hibernia, Florida. (M. W. Canby.) 



S. immersed ; filaments very much branched, solitary or subsolitary ; branches mostly unilateral, 

 branched; apices of the branches not attenuate, broadly rounded ; cells disposed in a simple 

 series, in the trichoma somewhat rounded, in the branches frequently angular, mostly com- 

 pressed, from equal to 4 times shorter than the diameter ; terminal cell cylindrical, obscurely 

 articulate; interstitial cells none ; sheath close, hyaline, not lamellate; cytioplasm ajriigin- 

 ous or brown, minutely granulate. 



Remarks. — This species was collected by Mr. Willi am Canby in a little marsh 

 pool near Hibernia, Florida. The branches are given off in abundance, mostly in 

 a unilateral manner, are often very long, and about equal in diameter to the main 

 filament, and give origin to numerous branchlets. The sheaths are very trans- 

 parent and very close. I have never seen them in any way lamellate or fibrous, 

 or of any color. The cells do not have very apparent walls. In the main fila- 

 ment and branches they are globose, or, more commonly, very much compressed, 

 but in the newer branches, and sometimes in the older, they are very angular. 

 The few cells near the end of the branches are so sliaped as to remind one of the 

 phalanges of the fingers. The last cell is cylindrical and has a number of cells 

 indicated in it. The color of the young cells varies from a deep bluish-green 

 to a ferruginous-brown — that of the older from a light bluish-green to ferruginous- 

 brown. 



Fig. 2 a, and 2 b, pi. 8, represent portions of filaments of tliis species. 



S. conipactus, (Ac.) Ktz. 



S. strato expanse, tomentoso, fuseo-nigro; trichomatibus elongatis ramulisquc adscendentibus, 

 apice interdum paullum attenuatis sed sspe clavatis, obtusis ; trichomatibus iiiternis e cellu- 

 larum serie simplici formatis, et plerumque moniliformibus ; cellulis diametro suba^qualibus 

 vel brevioribus, subglobosis vel subquadratis, saepe compressis ; cytioplasmate dilute caeruleo- 

 viride, subtiliter graiiulatis ; cellulis apicalibus cylindrieis et oscillarium niodo, si^pc indistinete. 



