Aigeu. 319 



IXIX. Tolypthorix Kütziug. 



A. Vaginne teuues. 



t CaeBpitosae, saepius natantes, pseudoramis patentibus ; vaginae ad 

 basiin ramormn saepe inflatae ; heterocystae saepe ad basim im- 

 plurimae. Plantae in aquis tranqnillis crescoiites. 

 Fiia 10 — 15 /« crassa; articuli breves, jumores doliiformes 



1. T. di'storta (Fl. dan.) Kütz. 

 Fila 9 — 12,5 ," crassa; articuli diametro aequules vel longiores 



2. T. lanata (Desv.) Wartin. 

 Fila 8 usque ad 10 /^ crassa; articuli diametro aequales vel longiores 



3. T. tenuis Kütz. 

 tt Caespitosae, penicillatae, regulariter pseudo-ramosae, pseudo-ramis 

 erectis 

 Fila 15 /" crassa. Plantae in aquis rapide fluentibus crescentes 



4. T. penicillata (Ag.) Thur. 



B. Vaginae paries et trichoma fere aequicrassi 



Fila libera 12 — 15 /" crassa; vagina mucosa superficie granulosa 



5. T. limhata Thur. 

 Fila in Stratum gelatinosum crustaceum irregulariter dense intricata, 

 14 — 18 /' crassa 6. T. conglutinata Borzi. 



XX. Desmonema Berkeley et Thwaites, 



Trichomata ad 10 /' crassa 1. D. Wrangelii B. et F. 



Trichomata tenuiora, usque ad 8 ^ crassa 2. D. floccosum (Menegh.) 



B. et F. 



XXI. Hydrocoriine Schwabe H. spongiosa (Grün ) Schwabe. 



.XXII. Diplocülon Naegeli D. Heppü Naeg. 



Tribus IV. Nostoceae Kützing (8 Gattungen mit 56 Arten). 

 -Subtribus I. Änabaeneae. Vaginae inconspicuae vel nuicosae diffiuentes, vel ge- 

 latinosae firmiores crassae. 



A. Fila flexuoso-contorta in thallum peridermide delinito cinctum 

 concreta XXIII. Nostoc. 



B. Fila subrecta, parallela, in thallum tiibulosum cylindricum moUe 

 agglutinata XXIV. Wollea. 



C. Fila subrecta libera aut muco molliori in Stratum indefinitum 

 vel in floccos irreguläres vel in laminas conglutinata. 



t Heterocystae et sporae iutercalares. 



Sporae solitariae , aut ab heterocystis remotae, aut hetero- 

 cystis coutiguae ; trichomata nuda vel vaginata, libera aut 

 muco involuta in strata vel in floccos amorphos aggregata ; 

 articuli diametro aequales vel longiores XXV. Änabaena. 

 Sporae cylindricae sparsae ; trichomata brevia in laminulas 

 plumosas vel fusiformes paralleliter ago:regata evaginata 



XXVI. Aphanizomenon, 

 Sporae seriatac ab heterocystis remotae, evolutione centri- 

 fuga: fila libera, vaginis tenuissimis saepe evanesceutibus 

 cireumdata ; articuli breves, depressi, disciformes 



XXVII. Nodularia. 

 tt Heterocystae terminales ; sporae heterocystis contiguae 



XXVIII. Cylindrospenmim. 



Subtribus II. Aulosireae. Vaginae tenues raembranaceae persistentes ; fila libera 



vel paralleliter agglutinata. 



Fila libera XXIX. Aulosira, 



Fila in thallum concreta XXX. Hormothavmion. 



XXIII. Nostoc Vaixcher. 



Sectio I. Plantae aquaticae, maculiforme."», adnatae, ambitu crescentes; 



fila arcte contorta CUTICULAKIA. 



Trichomata 3 8 — 4 /" crassa, dense contorto-flexuosissiraa; 



sporae sphaericae 8 — 10 /< crassae 1. N. cuticulare (Br6b.) 



B. et F. 



Trichomata 3,5 — 4/" crassa, laxiora; sporae sphaericae saepias 



6 fi crassae, in longas catenas seriatao * 2. N, maculifurme 



B. et F. 



