424 Myxophycese, HeterocystideEe, Nostoo. 



duro, perideniiide luteo-fuscescenti; trichoiiiatibus flexuosis, laxe 

 inipliciitis, ceijualibus, dilute serugineis ; articulis granulosis, ob- 

 longis, dimidiatis; heterocystis ellipticis. 



■ Hab.Hn fossis exsiccatis humidis ad Confervas et cuhnos gra- 

 minum prope « Viterbo » Italiae 'Kuetzing). 



53. Nostoc microtis Montagne Sertum Patagonic. et Floruhi Doliviens. 

 Crypt. p. o, SylL p. 468, Kuetz. Spec. p. 297, Rab. Fl. Eur. A.Ig. 

 II, p. 174. — Minimum, thallo ad 5 mm. longo, solitario, meni- 

 branacco, caeruleo pellucido, e basi angustata dilatato subcochleato 

 vel ditiormi, margine sinuato, lobis tum acutis tum truncatis; tri- 

 choinatibus curvato-flexuosis^ moniliformibus; articulis globosis, 

 arcte connexis, heterocystis duplo majoribus. 



Hab. inter muscos Hungariae, (Grunow), in saxis inundatis ad 

 Rio-Negro Amer. mer. (d' Orbigny). 



54. Nostoc poiysaccum Reinsch Freshw. Alg. of Kerguel. Isl. p. 208. 

 — Thallo coriaceo, irreguhiriter sphierico vel subreniformi, sub- 

 aureo-fusco, magnitudine seminis sinapeos usque pisi, intus caver- 

 noso, trabeculis vel lamellis percurso; tegumento finno, coriaceo, 

 fuscescente; trichomatibus centralibus paulo flexuosis; articulis 

 sphsericis, contentu olivaceo repletis, ad 4 [x. crassis; niembrana 

 distincta dupliciter striata; heterocystis sphtiericis, ceteris celhilis 

 paulo hitioribus, ad 5,5 [j.. crassis. 



Hab. in insulis Kerguelensibus (Eatonj. 



55. Nostoc liydrocoleoides Reinsch Freshw. Alg. fr. KergueL IsL 

 p 208. — Thallo ad instar Hydrocoleorum instructo, subtilissimo. 

 teretifurmi, prolongato, tegumento 11,2-22,4 [x. diam., distincto, 

 crasso, hyalino cincto; trichomatibus rectis vel paulo contortis, fasci- 

 culatim conjunctis, vaginulis hyalinis circumdatis, 2,2-2,8 [x. crassis; 

 heterocystis articulos paulo magnitudine superantibus, spbericis; 

 articulis diam. paulo longioribus, contentu pallide 89rugineo repletis. 



7?"«/?. inter Tolypotriche Naegelii Kuetz. in ins. « Ker- 

 guelen » (Eaton). 



56. Nostoc leptonema Reinsch Frcshw. Alg. fr. KergueL IsL p. 209. 



Tliallis sphicricis, 0,2-1,5 mm. crassis, paulo elasticis, arcte con- 



glomeratis; tegumento externo subcrasso, hyalino, homogeneo; 

 trichomatibus prolongatis, contortis, laxius (in majoribusj den- 

 siusve (in minoribus) intricatis; celhilis oblongis, polis attenuatis, 

 laxe conjunctis, 1,5-2,4 [x. crassis; heterocystis spha^ricis vel sub- 

 ellipticis, sparsis, ad 6-6 [x. crassis. 



Hab. in caulibus F o n tin al is sp. in insula Kerguelenyi (Eaton). 



