650 Bacillarieae, Fragilariaoeae. 



Familia XIII. Fragilariacaae (Kuetz.) em. 



FragilariaceiB Kuetz. [1844] Bacill. p. 42 emend., De-Toni [1890] Osserv. 

 tasson. Bacill. p. 905. 



Cellulai (frustula) ut in fara. Diatomacearum, septis internis desti- 

 tutae; valvfe siue costis transversalibus, tantum striis transversis pun- 

 ctatis ornata^, pseudorhaphe prsesente seu nulla, nodulo centrali ge- 

 nuino carentes, nonnuinquam elevatione annuliformi mediana (pseudo- 

 nodulo) instructae, nodulis terminalibus nullis vel prfe^^entibus. 



Phaeophora tum lamin?eformia, minuta, tum granuliformia. (Au- 

 xosporse ignotse). 



Conspectus generum. 



I. Frustula ut plurimum valde elongata, bacillaria, rarius ic fa- 

 scias conjuncta, saspe vero uno apice fasciculato-adflxa, dein libera. 

 Phaeophora laminceformia {SynedrecB; Cfr. etiam aonnullas Fragila- 

 rice [Staurosirce) species). 



Synedra Ehr. — Frustula solitaria vei flabellato-adQata vel stipitata; valvae 



structura variae, plerumque elongato-lanceolat;o vel bacillares, rectao, sub- 



inde pauUo arcuatae, sajpe pseudonodulo centrali instructte. 

 Thalassiothrix Cleve et Gr. — Frustula longissima per unum apicera e facie 



valvari minorem (e 1'acie connectivali majorem) stellatim pulvinulo armil- 



lasformi conjunota. 

 Ardissonia De Not. — Valvae Synedrce sed striis utrinque sulcis 1 vel pluribus 



interruptfe. 

 Toxarinm Bail. — Valvae Synedrce, valde elongat» et tenues medio apici- 



busque tumidae, irregulariter punctatoe, longitrorsum non sulculatce. (Ge- 



nus marinum). 

 Asterionella Hass. — Frustula Synedrce inferne incrassata et basi flabelli- 



formiter conjuncta; valvte lineari-subclavatae. 

 Desmogonium Ehr. — Frustula Synedrm ('^) isthmis gelineis crassis in flla- 



mentum concatenata. 

 ? lihabdosira Ehr. — Frustula lineari-quadrangula, levia, in series peculiari 



modo concatenata, pedicellata [Genus hinc Synedrce, illinc Desmogonio 



affine]. 



II. Fruslula plns minus elongata, sa^pissime in fascias conjuncta. 

 Phiieophora granuliformia vel imperfecte lamelliformia {Eufragi- 

 lariece). 



Fragilaria I.yngb. — Valvae symmetricng, ecostatae, polis conformibus; fru- 

 stula rectangularia, in fascias catenasve conjuncta (incl. Staurosira Ehr.). 



