FRESH-WATER ALG^ OF THE UNITED STATES. 59 



S. iniiuersiiiu, Wood, (sp. nov.) 



S. immersum cum algis altt-ris intermixtum et plantas aquaticas adliEerens ; trichomatibus 

 elongatis ; pseudoramulis j)lus minus distantibus, plerumque gemiuis, et e basi divergeuter 

 adseendentibus, brevibus aut elongatis; trichomatibus internis Isete aerugineis, interdum dis- 

 tincte articulatis, iuterdum inarticulatis, apice obtuse rotuudato, ajrugiueo; articulis diamcti-o 

 subffiqualibus vel brevioribus ; vaginid amplis, hyalinis, coloris expertibus ; cellulis pcrdu- 

 rantibus distinctis, singulis, iuterjectis, subcylindricis, diameti-o iuterdum fere duplo breviori- 

 bus, interdum duplo longioribus. 



Biam.— Sin. vag. yj^j,/ = .000415". Cum vag. tj§oj" = -00076". 



Hab. — In aquis quietis, Cumberland County, New Jersey. 



S. immersed, intermixed with other algae and adhering to aquatic jilaiits ; filaments elongate; 

 branches mostly geminate, more or less distant, short or elongate ; iiiteriia! lilaniciits bright 

 aeruginous, sometimes distinctly articulate, at others not so, apex obtusely rounded a:ruginous; 

 joints about equal to the diameter or shorter; sheath ample hyaline, cohirle.-s; lieterocysts 

 distinct, single, interjected, subcylindrical, sometimes about half as long as broad, sometimes 

 nearly twice as long. 



Remarks. — I found tlii.s plant in September, 1869, in Shepherd's Mill Pond, near 

 Greenwich, Cumberland County, New Jersey, forming, with other alga?, a floccu- 

 lent, greenish-black, slimy coating to the stems and finely dissected leaves of 

 Eaiiuiiculus aquatilis. The branches arc very few in number in most specimens, 

 and when they are more plentiful are apt to be short and abortive. Their apices 

 do not differ materially from their other portions. 



Fig. 9, pi. 2 a, represents a portion of a filament of this specimen magnified 750 

 diameters ; fig. 2 & a whole filament magnified 2G0 diameters. 



S. l\a;gelii, Ktz. (?) 



S. csesptoso-floccosum, bryophilum, nigro-viride; trichomatibus, plerumque sparse pseudora- 

 mosis, pseudoramulis(|ue elongatis et intricatis ; trichomatibus internis brevitor articulatis, sa?|ie 

 interruptis, saspe nonnihil moniliformibus, viridibus aut in state provecta brunneis; articulis 

 saepe sejunctis, diametro plerumque brevioribus, subtiliter granulatis; pseudoramulis plei'umque 

 singulis ; vaginis modice arctis, interdum subamplis, hand distincte lainellosis, niodice crassis, 

 hyalinis, coloris expertibus ant in aetate provecta dilute fusco-brunneis; cellulis perduranti- 

 bus nonnihil reniformibus, plerumque nnllis, basilaribus. 



Diam. — Fil. cum vag. plerumque y/uu" — max. 5550" ; S'"c vag. T^^jyu'i *''■'"• pcrdurant. lab. 



T5(T?)T long. j^uiJTJ • 



Siin.- — S.Nxgelii (Ktz.), R.-VBExnORST, Flora Europ. Algarum, Sect. II. p. 2.52. 



Hah. — In fonte, prope Belvidere, Centre County, Pennsylvania. 



Growing in small, blackish-green woolly mats attached to mosses; filaments mostly sparsely 

 branched, with the branches elongate and intricate ; internal filament shortly articulate, 

 often somewhat nioniliform, often Interrupted, green, or, in mature state, brownish ; joints 

 often disjoined, mostly shorter than the diameter, finely granulate; branches mostly single; 

 sheaths moderately close, .sometimes ample, not distinctly lamellate, rather thick, hyaline, 

 colorless, or, in old age, light fuscous brown ; heterocysts mostly wanting. 



Rcmarl-fi. — I found this plant in the large spring that supplies Bcllcfonte with 

 water, growing attached to mosses, so as to form little dark-green mats around 



