ENDOSPERM OF UTRICULARIA 15 
The micropylar haustorium, in contrast to that of the antipodal 
end, usually finds no receptive tissue before it, so there is little 
to encourage prolongation in that direction. Outside the thin 
zone of the nucellus lies the sterile micropyle or the fused in- 
teguments. Only in the case of anatropous ovules is there nu- 
tritive invitation beyond the integument, where further elonga- 
tion might tap the placental tissues. Mere inversion of the ovule 
is not sufficient, however, to insure suitable conditions for the 
development of a haustorium at the micropylar end. It is im- 
portant that there be contact with the placenta so that any pro- 
truding part may not enter a space system if extended beyond 
the micropyle. Further, there must be no serious growth move- 
ments, preliminary to, or especially after fertilization to alter 
the relations of these adjacent parts which are merely pressed 
together and are not organically connected. 
Utricularia offers favorable opportunity, therefore, for basi- 
lar outgrowth from the embryo-sae, and both the female game- 
tophyte and the endosperm participate in its development. 
After mid phase in embryo development it seems to be the only 
channel for transfer of food to the ovule. 
There is no development of vascular tissue in the funiculus, 
which gradually is subordinated until later it becomes a mere 
rudiment. The seeds are scarcely attached as they approach 
maturity, and may be lifted off from the receptacle in a coher- 
ing layer, so feebly do their funiculi support them. 
Utricularia thus presents an anomalous situation in that the 
embryo is nourished throughout its development by haustorial 
outgrowths. The fact that the developing seeds are held firmly 
in place between ovary wall and placenta, while lateral displace- 
ment is prevented by mutual pressure of the ovules, permits 
diminished emphasis upon funicular attachment and favors di- 
rect transfer of materials by means of the micropylar haustor- 
ium. The not infrequent abortions are probably due to dis- 
placement of ovules thus severing the soft suctorial organs. In 
any event the specializations here noted suggest that with 
greater liberty the female gametophyte and endosperm might 
offer in general greater variety of form and behavior. 
Such views are fortified by comparison of Utricularia with 
