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CHIAVE DELLE FAMIGLIE E DEI GENERI 
Zygnemàceae — Thallus filamentosus articulalus, articulis cylindricis arde conjunctis: 
vegelativis aequipolaribus , fructiferis lumidis v. inflatis. Membrana lamellosa e 
slratis pluribus formata. Endochroma effusum aul effiguralum , saepissime spira- 
le, niicleum plasmate radiante involutum , et granula amylacea includens. Ve- 
getatio fit divisione transversa cellularum; propagatio zygosporis, copulatione cel- 
lularum binarura ortis. 
Spirogyra — Fila arliculata, cellulis vegetativis cylindricis arde conjunctis, fructiferis 
tuniidis. Massa chiorophyliosa spirali modo, simplici v. duplici, in quaque cellula 
disposila, granula amyhicea involvens. Vegelatio divisione transversali cellula- 
rum, multiplicatio conjugatione et scnliformi et laterali 6t. Zygosporae globosae, el- 
liplicae, V. lenticulares, triplici membrana involulae, superficie laevi v. punctata 
(Char. eniend.). 
Mesocarpeae — Thallus filamentosus, articulis cylindricis plerumque elongatis , arde 
coitjunctis. Membrana pertenuis, massa chlorophyllacea laminam axilera longitu- 
dinalein efFormans. Vegelatio divisione transversali cellularum: propagatio conju- 
gatione genuflexa v. scaliformis. Zygosporae inter cellulas binas genuflexas con- 
jugiitas. 
Mesocarpua — Fila articulata, articuli cylindrici, elongati, aequipolares; massa chioro- 
phyliosa initio effusa, poslea in fasciam longitudinalem contrada, nucleum cen- 
trale et unum v. duo granula amylacea includens. Copulalio scaliformis, non- 
numquam genuflexa et plerumque sterilis. 
Desmidiaceae — Thallus unicellularis vegetatione terminali et ramificatione destitutus; 
cellulae aut liberae aut seriatim conjunctae, syinmetricae, medio plus minus evi- 
denter constridae et in duas semicellulas (hemicytia) distinctae. Membrana laevi, 
vel striata, verrucosa, punctata; plerumque initio mucum plus minus difiluentem 
exuiJyns. Endochroma viride effusum aul elBguratum et laminas chlorophyllaceas 
e centro v. axi cellulae radianles efformans, granulis araylaceis non deslitutum. 
Propagatio zygosporis immobilibus ex binarum cellularum conjugatione ortis. 
Closterium — Cellulae cylindricae v. fusiformes, reclae v. plus minus curvalae, apicibus 
sensim allenualae, in medio linea transversali unica v. 2-5 partitae; membrana 
laevi V. striata. Massa ciilorophyllacea , granulis ainylaceis sparsis v. seriatis 
in fascias longiludinaliter radianles disposila , et sub polis cellulae vesiculis binis 
hyalinis, corpusculis mobilibus minutissimis includentibus, praedita. Zygosporae 
sphaericae v. quadrangulares, 
Ccsmarimì — Cellulae oblongae v. cylindraceae v. elliplicae, medio plus minus pro- 
funde et tiansverse conslriclae, utroque polo oblusae v. rotundalae,panduraefor- 
mes; membrana laevi , punctata, vel verrucosa. Massa chlorophyllacea transverse 
radiata granulum amylaceum unicum involvens. Zygosporae muricatae. 
Slauiasirum — Cellulae liberae, medio constridae; setnicellulae a vertice 3-6 angula- 
res , radialae v. incisae, membrana laevi v. plerumque verrucosa, verrucoso- 
aculeal.i, piocessis simplicibus v. incisis armala. Massa chlorophyllacea in lami- 
nas binas v. plures axiies radians et granulum amylaceum involvens. Zygospo- 
rae sphaericae, armalae. 
