THE OVULE. 117-— 
of the nucleus, and of course to each other. The exostome, 
or aperture in the primine; and endostome, or aperture in 
the secundine, do not always correspond, as in the Euphorbia- 
cee, according to Mirbel. The radicle of the seed is always 
next to the foramen. These parts are seen in Fig. 43,—a the 
base or hilum of the ovule, where it is attached to the podos- 
perm, } the base of the nucleus, ¢ the secundine, d the pri- 
mine, e the apex of the nucleus, f the foramen, n the nucleus. 
See also Figs. 44, and 45. 
453. In what appears the normal structure, the primine, 
secundine, and nucleus, are connected to each other at the 
base of the ovule, that is, next to the placenta. _In this case, 
the axis or line of direction of the ovule is rectilinear, or or-— 
thotropous, and the foramen is at the extremity of the ovule 
opposite to, or farthest from.the hilum. See Fig. 43, next 
page. 
454. It sometimes happens that the base of the nucleus, 
or point of connection between it and the sacs, is at the apex 
of the ovule, the position being altered during the growth of 
the latter. In this case a bundle of vessels, called a raphe, 
(8, fig. 44), extends between the base of the ovule and the 
base of the nucleus, to supply the latter with nourishment. 
The raphe enlarges where it joins the base of the nucleus, 
forming the chalaza,(h, fig. 44.). In this case, the foramen 
and the apex of the nucleus are brought round, and are found _ 
near the base of the ovule. This results from the unequal 
growth of the different sides of the ovule, and is termed ana- 
tropous. See Fig. 44, next page. - 
445. In other instances, the ovule becomes curved like « an Z 
U, the inner sides of the curve adhering. This brings the __ 
apex of the ovule round near its base. But the base of the — 
ovule, and base of the nucleus are still at the same point, that 
_is, next the hilum; the apex of the nucleus being bent round — 
with the apex of the ovule. Tits structars 9 See ee 
Pen peg See Fig. 45, next page. ie 
456. These three varieties wil esi understood fom 
Site ee a 
