FRKS1I-YY ATKU ALUJi OF THE UNITED STA1 _>.( 



ha\e referred to N. vern-<>t>u with some little hesitation. Some of the fronds 

 were smootliMi, otht TS \i-ry decidedh warty. M\ specimens are old plants, 

 which h;i\f become hollow by tin- discharge ot" their internal contents. It is pos- 

 sibly on tliis account 1 have, not been al>lr to \eril\ the minute description giu-n 

 h\ I'rotevxir Uabenhorst. As tin- latii-r may not be accessible to sonic of those 

 wlio consult these pages, I append the latter part of it, which differs from that 

 \\( -n by myself from the American planK 



" Trichoinatihiis hVxtioso-cnrvatK quasi triplici online; ccntralibus pnrcioribus, 

 Mine impliratis, apices \risiis plus minus attennatis, articulis oblongis, sub- 

 (li>taiitilms. periphericis deiisin* sa-pe densissime intricatis, basi haud raro cellulis 

 biseriatis, articulis glohosis, arete conncxis, extremis (nonnisi in thallo vetusto 

 oc( urrunt) snbHagelliformibns, articulis oblongis, cylindraceis spha-ricisque sinnil 

 immixtis, distantibus; cellnlis perdurantibus spho?ricis interjectis terminalibusque, 

 nonniinqnam pluribns simnl seriatis articulonim diamctro duplo triplove mnjoribus." 



According to 1'rofessor Harvey (Nereis Bor. Amer., part iii. p. 114), this species 

 been collected by Dr. Lyall in pools of fresh water, Isle of Disco, and at 

 I!. chey Island, Arctic Regions; also by Mr. Fendler at Sante Fe, New Mexico. 



IV. alpinum, KTZ. 



V nijirMrc, iinimTsnm ; thallo suborbicularc, erccto, niemfiranaceo, ad ^ = | nnciatn lato, ad 

 lincaa iluas vel tree craeso, tcnaci, saturate olivaceo-fusco, la.>vi, eapc rugoso-plieato, cum mar- 

 ginc intcgro et plerumqne incrassato; trichomatibus varic curvatis, laxc vel nonnibil dense 

 implicatis; articulis fuscis vel dilute rerugineis plerumque globosis, sa-pe subtiliter granulatis, 

 arete conncxia; cellulis perdnrantibus spheericis plerumque articulorum diamctro paulo nia- 

 juribus, iniiTiluui subsqualibus, inteijectis vel terminalibus. 



Diam. Artie, vegctativ. .00016" 00023"; cell. pcrd. .00026. 



" N, alpinum, KTZ. Phycol. General., p. 206, No. 10." RABENDORST, Flora Europ. 



Algnrum, TO), ii. p. 174. 



"A*. Xutherlandi, DICKIK." HAKVET, Nereis Boreal! Americana, part iii. p. 114. 

 " N. crixtatum, BAILEY." HARVEY, Nereis Boreali Americana, part iii., 1857, p. 114. 

 Growing attached by its margin to the- rocks in running water; thallus snborbicnlar, erect, 

 mcmbranaccous J j an inch high and 1 3 lines thick, very tenacious, deep olive-green, 

 smooth, often rugosely plicate especially at the base, with the margin entire, rounded, and 

 mostly thickened; filaments variously curved, laxly or somewhat densely interwoven; arti- 

 cles fuscous or greenish, mostly globose, often finely granulate, closely connected ; hcterocysts 

 spherical, generally a little larger than the ordinary cells, sometimes about equal to them, 

 interspersed and terminal. 



Remarks. This interesting little plant was found in the mountain rivulets 

 near West Point, New York, by the late Prof. Bailey, and received from him the 

 ific name crwtatitm, first published in Harvey's work on the North American 

 Alga>. I have myself seen it growing in very great abundance in rapid mountain 

 ins in the central portions of this State. It is doubtless, therefore, an inhabi- 

 tant of the whole Allegheny range. In the low country, east or west of these 

 mountains and their outlying hills, I do not know of its having been found. I have 

 very recently received specimens of a nostoc from Sereno Watson, Esq., undoubt- 

 edly belonging to this species, which were collected by himself, in cold streams in the 

 Clover Mountains, Nevada, at an altitude of 11,000 feet. Under the name of M. 



