74 FRESH-WATER ALGiE OF THE UNITED STATES. 



contortis; ramulis abbreviatis vel nonnihil elongatis, apice obtuse rotundatis; ramulorum et 

 trichomatam cellulis tri-multlseriatis, pleruraque pachydermaticis, ferrugineo-fuseis, enormiter 

 globosis, homogeneis ; cellulis apicalibus interdum breve cylindricis, baud articalatis ; vaginis 

 sat amplis, luteo-brunneis vel dilute ferrugineo-brunneis. 



Diam. — Max. trich. cum vag. t^^I^" = .0013". 



Syn. — S. guttula, Wood, Prodromus, Proc. Amer. Philos. Soc, 1869, p. 132. 



Hob. — South Carolina, in Taxodium distichum. (Prof. Ravenel.) 



Arranged in small, thin, black spots, vrhich are generally round, but sometimes irregular : fila- 

 ments closely interwoven, very much branched, rigid, unequal, subcylindrical, somewhat con- 

 torted ; branches abbreviate or somewhat elongate, apex obtusely rounded ; cells of the 

 trichoma and branches 3 to many seriate, mostly with thick coats, ferruginous-fuscous, irregu- 

 larly globose, homogeneous ; apical cells sometimes shortly cylindrical, not articulate, sheaths 

 ample, yellowish-brown. 



RemarTcs. — This species was found growing on the bark of Taxodium distichum, 

 by Prof. H. W. Ravenel, in South Carolina, and by him given to Dr. Billings, 

 U. S. A., to whom I am indebted for specimens. It forms on the bark minute 

 roundish, blackish, dot-like spots of about a line in diameter, or sometimes, appa- 

 rently, by the coalescence of two or more of these -spots, larger irregular patches. 

 The habit of the plant is a rigid one. The main stem is often irregular in size, 

 variously bent and rebent, and mostly gives off a number of branches, which fre- 

 quently nearly equal the main filament in size, and like it are bent in various 

 directions. They also frequently give origin to numerous short branches. In 

 some instances, there is a distinct apical cell, which is cylindrical, but only two or 

 three times longer than broad ; in many cases, however, this cylinder being want- 

 ing, the ordinary cells extend to the extreme apex. 



Fig. 4 a, pi. 8, represents a filament, and fig. 4 h, the end of a branch magnified 

 460 diameters. 



S. acerTatns, Wooir. 



S. in guttulis minutissimis, subcrnstaceis, nigris, in strato subcontinuo ssepe aggfegatis; tricho- 

 matibus parvis et brevibus, rigidis, admodum in8equalibus,.prostratis, tuberculis, arete et dense 

 ramossissimis, virldibus aut aureis aut brunneis ; ramulis brevibus, plerumque baud ramulosis, 

 ereetis aut ascendentibus, sape abbreviatis et papilliformibus, obtusis, ssepe lateraliter connatis ; 

 cellularum serie in trichomatibus multiplici in ramulis plerumque simplici ; cellulis subglobosis 

 vel subangularibus, viridibus, baud distincte granulosis, in ramulorum apice ssepe breve cylin- 

 dricis et interdum obsolete articulatis ; vaginis aureis, nonnihil hyalinis. 



2)ia»n.— Trich. max. ^J^^' 5 ram. 75V— tsV- 



Syn. — S. acervatus, Wood, Prodromus, Proc. Amer. Philos. Soc, 1869, p. 132. 



Hab. — South Carolina, in cortlce (Ilex opaca). (Prof. H. W. Ravenel.) 



Arranged in drops, which are very minute, subcrustaceous, black, and frequently aggregate into 

 a subcontinuous stratum ; filaments small and short, prostrate, rigid, somewhat unequal, tuber- 

 culate, densely and closely branched, green or golden or brow^n ; branches short, for the most 

 part not branched, erect or ascending, frequently abbreviate, and papilliform, obtuse- series of 

 cell multiple in trichoma, mostly simple in the branches; cells subglobose or subangular 

 green, not distinctly granulate, in the apices of the branches frequently shortly cylindrical and 

 sometimes obsoletely articulate ; sheaths golden, somewhat hyaline. 



