304 
To TT L Ä’XIÄ 
» 0ph,„ g | „„„, i„,„„ ce , „ f lh , inco „„ ; tlo p „ 0( *2 i„di. 
"■ TT- Fro " * '»"p*“" r** °t vi» i Z„“"d 
11« talZcrX“"'“ WiCl ' ■ re /»" <l ” ■“"> «»» »n« .«rl«, «f 
j . ^ 0&ams ’ ab primitive in character, and as indicatin«- 
iZt'Si r™ si * wh ~ di "“' «* - 
by 10,atlon from »nie such United ancestral archesnorium 
z::z" 
y gial soll were the more primitive, it is‘ not difficult 
to conceive how in plants growing in meist ani shaded position! 
° d “ ger ° f ex P° sure t0 drought is minimised, the sporangia 
gl have become not only completely separate, but also reduced 
IL ’ “ S P T° See ln . the pr ° greSsion through the Osmundaceae to 
y Leptosporangiate Ferns: and parallel with this reduction 
the 10 Sp ° rangmm ’ as 1 have sllown elsewhere, would have proceeded 
the reduction in mass of all the other members of the sporophyte « 
F in M"fi , , H {P° thesen ergibt sich für die Natur der sterilen 
Fällen d r -f 1C , SchlussfoI gerung; es müssen nämlich in beiden 
Fallen die sterilen Farnblätter ursprünglich fertil gewesen sein u d 
hatten somit erst im Laufe ,i Q „ <j-. b SLln > una 
inende Fn„eH 7 c dle lhnen von Haus ™kom- 
e Function der Sporenproduktion eingebüsst. Prantl bekennt 
ZdTZrn ftf X ", - •»- “ 
dun cs 111 p . -66 folgendermaassen heisst: 
„rrom it we recognise that the ascending series shows a pro 
gressive Sterilisation of the tissues of the neutral Generation and 
an increasing e.aboration of external form and inSTÄ^ Z 
h " eS ° f ,W e - going- - a measure, band in band. ’ 
function ^ ‘‘ f® pi '°S ression were as above stated, the 
.« sporophyte i„ p„,„ tim ,. spo „. prod „ d „* JZe’.T“ 
fh.s Sense, be termed primary from the point of view of descent and 
the vegetative members, secondary; the morphology of spore produ 
cing members should accordingly take precedenoerf the mo plm 0 
of vegetative members.“ murpnoiogy 
, r/ antl ’ SChe Und ^ower'sehe Hypothese steht einer an- 
icicn u assung gegenüber, die bisher wohl die meisten Vertreter 
gefunden hat, und welche die fertilen Blätter der Farne als meta- 
