416 Myxophycese, Heterocysfcidese, Nostoc. 



culis omnibus globosis, confertis, 3,5-4 [i. diam.; lieterocystis in- 

 terstitialibus, articulis paulo majoribus, 7-7,7 [x. diam. 



Hab. in plantis aquaticis, imprimis in foliis Myriopbylli et Ra- 

 nunculi aquatici in Germania (Kuetzing, Rabeniiorst), nec non 

 in Austria (Beck) Polonia (Alexenkoj, America boreali (Wolle) 

 et in Cladophoris Californiae (Ander^-on). — Sec. icon. a cl. Kuet- 

 zing exhibitam, hsec species paullum differre videtur ab affini N. 

 cceruleo Lyngb. 



4-2. Nostoc caeruleum Lyngbye Hydrophyt. Dan. p. 201, t. 68, f. B, 

 1819, Ag. Syst. p. 22, Grev, Scott. Fl. III, p. 131, Spreng. Syst. 

 Veg. IV, p. I, pag. 372, Harv. in Hoolv. Brit. Fl. Vol. II, p. I, 

 p. 400, Man. p. 185, Breb. et God. Alg. des env. de Falaise p. 38, 

 Kiitz. Phyc. gen. p. 205, Phyc. germ. p. 169, Sp. Alg. pag. 296, 

 Tab. phyc. If, pag. 2, t. 3, f. IV, Desm. Phmt. crypt. de France 

 ser. I, n. 1979 (fide Borneti), Aresch. Alg. scand. exsicc. n. 36! 

 Menegh. Monogr. Nostoch. italic. p. 111, Hass. Brit. Freshw. Al- 

 g« pag. 293, t. 7, Rab. Deutschl. Krypt. p. 64, Fl. Europ. Alg. 

 H, p. 167, Alg. exs. n. 1453! Crouan Fl. du Finist. p. 111, Heufl. 

 Enum. Crypt. It. Venet. pag. 88, Wood Contribution to the Hi- 

 story of the freshw. Alg. of N. Am. pag. 31, Aresch. in Rab. Alg. 

 exs. n. 1453! (ex. optim.), Kirchn. Algenfl. von Schles. pag. 234, 

 Wittr, et Nordst. Alg. exs. n. 98! Hansg. Neue Beitr. zur Algenk. 

 Bohm. p. 7, Cooke British Freshw. Alg. pag. 233, t. 92, f. 4-6, 

 Born. et Fhih. Rev. IV, p 213, Hansg. Prodr. II, p. 66, D.^' Butler 

 iii ColL H. et Setch. Phyc. bor. Amer. n. 1166! Lagerh. in W. et 

 N. Alg. exs. n. 892! Elfv. in W. N. et L. Alg. exs. n. 1325! No- 

 stoc Wallrothianum Kiitz. Phyc. gen. p. 205, Phyc. germ. p. 169, 

 Sp. Alg. p. 297, Tab. phyc. II, p. 2, t. 4, f. II, Nostoc gregarium 

 Thur. in Kiitz Sp. Alg. p. 290, Tab. phyc. II, p. 1, t. 2, fig. 11, 

 Rab. Fl. Europ. Alg. II, p. 181, Thur. in Rab. Alg. exs. n. 2174!, 

 nec n. 1340, nec Hantzsch, Nostoc Itzigsohni Rab. FI. Europ. 

 Algar. II, p. 168, Itzigs. et Rothe in Rab. Alg. exs. n. 127! et 550! 

 Nostoc cwrulescens Rab. Alg. exs. n. 745! Nostoc sphxricum 

 Breb. in R:ibenhorst Algen, n. 1309! Nostoc cceruleiun b. cceru- 

 lescens Rab. Fl. Europ. Algar. H, p. 168, Nostoc cceruleum c. 

 Wallrothianuin Rab. Fl. europ. Algar. II, p 168, Nostoc liche- 

 noides Hausm. in Erbar. crittog, ital. ser. II, n. 337! — Thallis 

 parvulis, ad 5-6 mm. diam. giobosis, solidis, levibus, nerugineo- 

 cteruleis vel fuscescentibus, pellucidis, solitariis vel aggregatis, 

 haud infrequenter proliferis, peridermide firmo tenaci; filis dense 



