OVULK, 



83 



cellular substance, nearly transparent, with its base fonnir.^r a 

 part of the wall of the ovary. If we examine a bud a Httle 

 later, we shall find a ring swelling out from the base of the 

 nucleus, expanding and rising round it, and forming a partial 

 covering to it. (Fig. 136, 2, cc.) This first integument is 



d . 



Fig. 136. 



»i, tte nnclens ; a, lie secnndine ; 6, the primine ; /, the fanicRlus ; h, tte hilnra. 



Fig. 13,1 



called the ^ecundine by Mirbel, and is scarcely formed when a 

 second makes its appearance in the same manner, which is 

 called ikiQ primine, and both increase until they present the a}>- 

 pearance represented in Fig. 136, 3, in which n represents the 

 nucleus, a the secundinc^ or internal membrane of Brown, the 

 inner envelope, and b the prviune^ or external membrane of 

 Brown, which is the outer one. These continue to increase 

 until they inclose the nucleus entirely, leaving only a micro- 

 scopic orifice, called ih.^ foramen^ in the ovuie, and micropyle in 

 the seed. 



137t This is the mode of dev^elopraent 

 of all ovules that have integuments around 

 the nucleus. The ovule is attached to 

 the ovary by a bundle of vessels, of greater 

 or less length, which is called i\\Q fmiicn- 

 ius. (Fig. 136, I,/,) The point of at- 

 tachment to the ovule is called the ki~ 

 lum. (Fig. 136, 2, k.) The hilum is 

 always the base^ and the foramen the 

 apex of the ovule, 



138. When the parts are developed 

 as above described, that is, when the nu- 

 cleus remains in its original position, witli 

 its base next the placenta, and its apex in the opposite direc- 

 tion, the ovule is said to be ortholroixiKS [ortkos, straight, 



r, the raphe. 

 ch, the chalaza 

 o, foraraen. 

 n, niic?eus. 

 a, sccundine. 

 h, prirr.ine. 

 /, funiculus. 

 ft, hitura. 



"What do vre find later? What did Mirbel call it? What next makes 

 its appearance ? What is it called ? What is the foramen ? What is it 

 called in the seed ? — 137. How is the ovule attached ? What is it called ? 

 What is the Ililum ? What is the base of the ovule ? What is the apex f 

 138 When is the ovule orthotropous? 



