F R i: S II \V A T K II A L JE OF TUB UNITED S T A T K 8. 27 



has In i 11 sli ( i\Mi. hut only reason td stiitly also their relations with thv \ari- 

 eollema. 



In n-ijaril t<> tin- >/ / iiKvii-nt . tin n- i- as yet no direct proof whatever connect- 

 ing thrin \vitli lirliciis. It i- \< i\ possible that they are not so closely related to 

 the true nostocs as is tjencrally ln-li-vril, so that the prohahilitii-s of their being 

 licln-iis an- at present so remote, tliat for the sy-tt-matist to refuse to take note of 

 their distinct forms seems to me m.t unwarrantable. 



SIBKAMII.V NOSTOCE^E. 



Tliallus JM riiliTiiintr plus minus distincto instructus, sporis dcstitutus. 



Thullns providril with a more or less ili-iim-i int> innm-nt, and destitute of spores. 



( ienus NOSTOC, VAUCHEB, (1803.) 



Tli.i!''i- iri l:iiiii<isn<. v:irii- cnlnratus, aut globosus vel Rul>plobo8n8 .nu foliacoo-memhrannceug ct 

 irr. triilurit.T cxpansus, su-pc Imllutus. Trii-buniuiu plus uiiuus niouiliformia. Cclluto perdurantca 

 >pli:iTi.-.r vi 1 rare oblongc. 



Ttialliis pi'lntinoiis. variiiii-ly colored, pitlirr plohooc or BnbgloboM, or folincoously incmbranoiiB 

 ami inilriiniiclv expanded, often a liiillu. FiluinenU more or less monilifonuo. HctcrocjsU exactly 

 hplit-rii-al or rarely oblong. 



a. Ttiallus globiisus vel subylobotvt. <;-l tl,.<,-iformi. 

 Thallus ijll*>*f, Hiilxjlobose or discoid. 



IH. Auolmii. \V.K)D, (sp. nov.) 



.li-_ p liil)i>siiiii, |iiirvuni, plornniquo innpnitndinr ovorum piscium, rare ad 2", fuscescente, 

 vel nigresccnti-, intrnluin durum inlt-riliiin Mihnmlle, superGcie sii'pc corrugata ; tricho- 

 mntilms varic curratis, dense intrioatis rel dintantibos et lazisHime intricatis, viridibus, 

 t'u.-r, -. -iitilms, suliplunilM-is vcl lutco-brunncis, in thallis minoribus saepc distincte vaginatis, 

 in thullis majorihus liaud TC-1 inilistiiic-tc vaginatis ; articulis .maturis globosis, saepc didvmis, 

 crasso granulatis; cellnlis perdurantibus articaloruin diamctro ocqaalibus vcl paulo majoribus, 

 glol>osis, interjcctis rcl tcrminalibus, plerumquc sparsis. 



Diam. d-ll. V.-p, T ^ n ,"_ TT ^ Tr " - .002C" 00033"; cell, pcrdnrant, .00033". 



Hob. in rupibus irroratis, New Jersey. (Austin.) 



Sol)jtlolK)so, small, mostly the size of fish-cgga, but reaching the diameter of nearly two lines, 

 fu--ou8 or blackish, sometimes very hard, sometimes much softer; surface often corrugated; 

 filaments variously curved, densely intricate or distantly and loosely interwoven, greenish, 

 fuscous, subplumbeis or yellowish-brown, in the smaller fronds often distinctly vaginate, in 

 the larger indistinctly or not all vnginate ; mature joints globose, often didymons, coarsely 

 granulate; hetcrocysts equal to the diameter of the other joints or a little larger, globose 

 interspersed or terminal. 



I,'' marks. The fronds of this distinct species vary greatly in appearance; the 

 larger of them are often almost colorless, and, when viewed with the microscope, 

 an seen to be composed of a transparent colorless jelly, with remarkably large 

 filaments scattered through it. These filaments are generally without sheaths, 

 though occasionally a sheath can be faintly traced. The smaller fronds are much 

 firmer than the larger and are more decidedly colored. Some of them are entirely 

 opaque, looking simply black when viewed by transmitted light under the micro- 

 scope. In these the filaments are densely crowded together, often misshapen and 



