778 



quam maxime varise, cylindrace;», fusoidea^, lunatse, dolioliformes, 

 biscoctiformes etc, ssepe medio plus minus constricta? et e partibus 

 duabus symmetricis (semicellulis) saepe varie crenatis vel iaciniatis 

 constantes, Clilorophora tum centralia, radiantia, tum axilia vel pa- 

 rielalia, laminaria, recta vel spiraliter convoluta, pyrenoides 1-plu- 

 res foventia. Membrana ut plurimum tenuis, levis vel superricie ru- 

 gosa vel veiTucis aut aculeis obsita, quandoque tegumonlo seu va- 

 gina mucoso-gelatinosa obvoluta. 



Propagatio cellularum divisione binaria vegetativa '); zoogonidia 

 nulla 2). 



Generatio zj^gotis ex aplanogametorum copulatione ortis ^). Con- 

 jugatio (parallela vel cruciata) inter 2 cellulas liberas ^). Cellulae 

 utrfeque conjugantes plerumque gelatina obvolvuntur. Zygota (zy- 

 gosporae auct.) pro more membrana raedia firma, interiori et exte- 

 riori molhbus instructa, globosa, angulata, levia vel sa^pe verrucis, 

 aculeis aliisve prominentiis obsita, in conjugationis canale efformata, 

 post longam periodum (hibernationem) germinantia. 



Conspectus subfamiliarum 



Eudesmidiece. CelluUc (post divisionem) in tihimenta saepias vagina gelati- 

 nosa obvoluta conjunctie, plerumquo aiite conjiigationis actum seceJentes. 



Cosmocladiece. Cellulfo cosmarioidece h. e. medio constrictae, per fllamenta 

 liyalinula, dichotomo-ramosa conjunctai. 



Didj/mioidece. Cellulae (post divisionem) omnino diseret:t! (nec ergo iu fllamenta 

 adhajrentes neque per fllaraenta hyalinula, ramosa conjuncta;,*. 



Subfamilia prima Eudesmidieae Hansg. 



Eudesmidiece Hansg. [1888] Prodr. p. 167, De-Toni [1888] Consp. geu. Chlo- 

 roph. in Notarisia 111, n. 10, p. 452, 



1) Cfr. Fischer Ueber die Zelltheilung der Closterien in Botanische Zei- 

 tung 41. Jahrg. 1883. n. 14-17, Taf. III, 



2) Zoogonidia qute olim in Desmidiacea quadam vidisse asseruit cl. Ar- 

 cher (On tlie occurrence of zoospores in the Family Desmidiacep in Proeeed. 

 of the Nat. Hist, of Diiblin vol. III, part I, 18'j9-60, p. 21, pl. I), sunt vero, 

 observante P, A. Dangeard, Chy/ridiacece cuidam adscribenda. 



3) Cfr. de conjugationis modo, zygotorum germinatione etc. De-Bary Co- 

 njug. 1. c, Hansg, Prodr. p. 166-67. 



4) In Desmidiaceis fllamentosis [Hyalolheca ete.) cellnlae ante conjugatio- 

 nem dilabuntur. 



