304 BOTANICAL GAZETTE [ NOVEMBER 
nate. The lowest ovule, having no ovule below to sustain it, 
may descend into the hollow at the bottom of the pistil. 
In Caltha leptosepala the ovules are mostly alternate, and are 
fewer in number than in the pistils of Delphinium, the difference 
being apparently compensated by the greater number of pistils 
in the former. The only other difference worthy of mention is 
that the ovules of Caltha are two-coated, while those of Del- 
phinium have only one integument (fig. 37). 
ALISMACE., 
The two genera studied were Sagittaria and Alisma. These 
are in the main, alike so far as the development of the pistils is 
cerned, for the slight differences that do occur are easily explica- 
ble by the difference in number of the pistils, involving their 
relations to each other and to the receptacle. Thus in Adsma 
Plantago aquatica L. there is but a single whorl of pistils, while 
in Sagittaria latifoha Willd. the ovules are very numerous and 
arranged spirally over the whole surface of the receptacle. 
SAGITTARIA LaTIFOLIA. In this plant, as in Myosurus, the 
pistils are developed acropetally. Each pistil makes its appear- 
ance as a papilla on the side or summit of the spherical recep- 
tacle. As this papilla enlarges it grows so as to leave a hollow 
onthe upper side. In its axil there now appears a second papilla, 
which grows out into the space between the laminae of the 
pistil, which has now become somewhat curved. As _ these 
laminae increase in width they surround the ovule entirely except 
the very slightly developed ‘axillary placenta.” Asa result of 
this the ovule appears to arise from the floor of the pistil, as 
indeed some descriptions aver (figs. 33-35). While the pistil 
has been thus developing, the ovule has not remained unchanged. 
It has increased in length, and about half way from base to 
apex makes a sudden turn, at which place the two integuments 
arise. The ovule continues to bend upon the funiculus until by 
the time that the integuments have reached the apex of the 
nucellus the latter lies parallel to the surface of the receptacle, 
with its apex pointed away from the apex of the receptacle (fig: 
