163 



N. tenuissimum (Hormosiphon tenuissimum Ktz. Phycol. gener. 

 p. 209. N. 1.). N. aquatieum, globosum aut subglobosum, pisiforme, 

 fasoescena; fcriohomatibua ralde intricatis, distincte vaginatis, dilute 

 aerugineis ; articulis ohlongis, laxe conncxis, diametro subduplo longiori- 

 bua ; vaginis erassis, homogeneis, luteolis. v. v. 



Diam. articul. l /i000 — V»Oo'" = 0,00008 — 0,00009", vag. 1/280 

 -' >•>>'" — 0,0003—0,0004", cell. perdurant. l / 7 7o'" = 0,00011". 



Hab. in stagnis, fossis, per Europam passim. 



N. rupestre Ktz. (Spec. p. 296. Rabenh. Alg. N. 87., inprimis 

 645 b ! omnia evolutionis stadia includens, unde patet, species Kiitzingii 

 sequentes huc pertinere: Hormosiphon furfuraceus, gypsophilus, macro- 

 siphon! Nostoc gregarium Hantzsch in Rabenh. Alg. N. 1340. non 

 Thuret!). N. thallo parvo, globoso, olivaceo - fuscescente , peridermate 

 plus minus evoluto, saepe in crustam irregularem , praecipue aere sicco 

 furfuraceam dense aggregato ; trichomatibus laxe intricatis , articulis 

 oblongo-rotundatis, initio remotis , deinde approximatis , densioribus ; 

 vaginis plus minus crassis, saepe crassissimis et saepius distincte lamel- 

 losis, (ratione aetatis et partim loci natalis) achrois, luteolis, fuscescenti- 

 bus vel aureo - fuscis. v. v. 



Diam. trich. Vsoo — V^o'" = 0,00011 — 0,00025", vag. l /267— 

 7st"' = 0,00033— 0,0017", cellul. perdur. Vboo"— 1 /^'" =0,000 17" 

 —0,00027". 



Hab. in muscis , rupibus , ericetis humidis per totam Europam, 

 saepe in consortio Chroococci turgidi. 



N. granulare (Hormosiphon granularis Ktz. Spec. p. 301. N. 4. 

 Tabul. I. T. 94. sub Anabaena). N. subglobosum, magnitudine seminis 

 sinapeos vel pisi et ultra, olivaceo- vel aerugineo-fuscum, nigrescens ; 

 trichomatibus pallide aerugineis, plus minus flexuoso-curvatis , distincte 

 vaginatis; articulis globosis, subtilissime granulatis, arcte vel laxius 

 connexis ; vaginis sat amplis, luteolis, his illisve diffiuentibus. v. v. 



Diam. Vsoo— Voo"' = 0,00011—0,00014", cell. perd. 7332'" = 

 0,00026". 



Hab. in terra nuda limoso - sabulosa, in campis humosis passim. 



N. macrosporum Menegh. (Nost. p. 116. N. 8. T. XIV. F. 2. N. 

 crassisporum ilenegh. Consp. Alg. Eugan. p. 7. Hormosiphon macrosporus 

 Ktz. Spec. et Tabul. Diplocolon Heppii Hantzsch inRabenh. Alg. N. 1339 !). 

 N. thallo minimo. solido, polymorpho (globoso, oblongo velcylindrico), aeru- 

 gineo-viridi vel olivaceo-fuscescente, peridermate pellucido cincto; 

 trichomatibus fiexuoso - curvatis , laxe intricatis, saepius spiraliter con- 

 volutis ; articulis sphaericis vel subcompresso - sphaericis , aerugineis vel 



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