Myxophycege, Heterocystidese, Nosfcoc. 423 



VEY, WooD, WoLLB, lUiLEY, Setchell, Tilden) et Antillarum, lii 

 iiis. (liuulaliipii (Maze). 



50. Nostoc calidarium Wood Freshw, Alg. of tlie U. S. p. 34, t. 2, f. 2. — 988 

 Thallo maximo, indefinite expanso, uiembranaceo-coriaceo v. mem- 

 branaceo-gelatinoso vel membranaceo aut laete viridi vel sordido 

 olivaceo-viridi vel olivaceo brunneo, irregulariter profande iaci- 

 niato-sinuato, demuni eleganter laciniato; trichomatibiis insequali- 

 bus, interdum flexuoso-curvatis, plerumque subrectis et arcte con- 

 junctis, in formis duabus occurrentibus: forma altera parva, vi- 

 ridi, articulis cylindricis, cum cellulis perdurantibus hic illic in- 

 tercalaribus, vaginis interdum obsoletis, ssepius diffluentibus; forma 

 altera maxima, articulis globosis v. oblongis, aurantiaco-brunneis, 

 heterocystis ab articulis ceteris haud diversis. 



Hab. in aquis thermalibus « Bentoii Springs, Owen Valley, 

 California » Amer. bor. (Partz). 



Sectio IX. Zetterstedtiana Born. et Flah. R^v IV^, p. 220. — Aquaticae, glo- 

 bosaa; thallus durus, in lobulos radiatim facile secedens. 



51. Nostoc Zetterstedtii Areschoug Alg. Scand. exs. fasc. IX, n. 386, 989 

 Rab. Alg. exs. n. 2399! Wittr. et Nordst. Alg. exs. IV, n. 193, 

 Born. et Thur. Not. Alg. II, p. 120, Wille Bidrag till Sydame- 

 ricas Algflora, in Bih. till Kongl. Svensk. Vet. Ak. Handl. VIII, 



p. 44, Born. et Flah. Rev. IV p. 220. — Thallo globoso, usque ad 

 1 cm. diam., duro, subviridi, coriaceo, extus verrucoso, in lobulos 

 radiatim facile secedente; filis a centro radiantibus, flexuosis, ad 

 superficiem thalli densissime intricatis; vaginis exterioribus distin- 

 ctis, luteis vel hyalinis, interioribus conflueiitibus hyalinis; tricho- 

 matibus 4 jjl. crassis, iniiequalibus; articulis subglobosis vel oblongis, 

 diametro paulo longioribus; heterocystis subsphaericis, rarius ob- 

 longis, solitariis vel seriatis, 8-15 [x. crassis, tegumento saepius in- 

 crassato. 



Hab. libere natans in lacubus Suecias (Zetterstedt, Montelin! 

 ScHENTZ, Hylten, Cavallius, Nordstedt, P. T. Cleve), FenniiB 

 (Elfving), Danige (Rostrup, Baagoe, Nordstedt, Kolpin, Carn), 

 in lacu Taupo Australiae (Nordstedt). — Forma minor Willc 

 « Napocta grande y Sierras Pampeanos » Argentinoe (Wille). 



Species dubise. 



52. Nostoc tuberculosum Kuetz. Phycol. gener. p. 206, n. 9, Rab. Fl. 990 

 Eur. Alg. II, p. 182. — Thallo olivaceo-atro, tuberculato, compacto. 



