Botany of the Southern states . esent the ap-pearance represented in Fig. 136, 3, in which n represents thenucleus, a the secundine, or internal membrane of Brown, theinner envelope, and b the primine, or external membrane ofBrown, which is the outer one. These continue to increaseuntil they inclose the nucleus entirely, leaving only a micro-scopic orifice, called the foramen, in the ovule, and micropyle inthe seed. 137. This is the mode of developmentof all ovules that have integuments aroundthe nucleus. The ovule is attached tothe ovary by a bundle of vessels, of greateror less length, which
Botany of the Southern states . esent the ap-pearance represented in Fig. 136, 3, in which n represents thenucleus, a the secundine, or internal membrane of Brown, theinner envelope, and b the primine, or external membrane ofBrown, which is the outer one. These continue to increaseuntil they inclose the nucleus entirely, leaving only a micro-scopic orifice, called the foramen, in the ovule, and micropyle inthe seed. 137. This is the mode of developmentof all ovules that have integuments aroundthe nucleus. The ovule is attached tothe ovary by a bundle of vessels, of greateror less length, which is called the funicu-lus. (Fig. 136, 1,/.) The point of at-tachment to the ovule is called the hi-lum. (Fig. 136, 2, h.) The hilum isalways the base, and the foramen theapex of the ovule. 138. When the parts are developedas above described, that is, when the nu-cleus remains in its original position, withits base next the placenta, and its apex in the opposite direc-tion, the ovule is said to be orthotropous (orthos, straight,. r, the , the chalazao, , nucleus. a, secundine. b, , hilum. What do we find later ? What did Mirbel call it? What next makesits appearance ? What is it called ? What is the foramen ? What is itcalled in the seed ?—137. How is the ovule attached ? What is it called?What is the Hilum ? What is the base of the ovule ? What is the apex ? 138 When is the ovule orthotropous? 84 OVULE. and tropos, form). This is the case in comparatively fewplants. The Polygonums, Nettles, Walnuts, and a few others,are in this manner, but scarcely ever the Monopetalge. Oftenerthan otherwise the ovule undergoes changes during its develop-ment, so that the various parts bear very different most frequent change is where the ovule is completely re-versed ; that is, the apex of the nucleus is in contact with theplacenta, and the base of it in the opposite direction. In thiscase the bundle of vessels that we called the funiculus
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