126 



ACADEMIC BOTANY. 



285, The number of cells is determined by the styles; the free 

 stigmas; the stigma-lobes ; the placenta;. 



Fia. 180.— Ovules. A, Pellitory-on tlie-Wall (Parielaria offiiAnala). Ti, Groundsel 

 {Senecw vulgaris). C^'P&o.^Oiwnis rolundifolia). D, Mezereoa (Daj^Ane). E, Mare'a-tail 

 {jSippuris vulgaris). F, Horse-cheBtnut {^scidw hylyrida). 



286. Abortion. — The Filbert is 2-eelled at first; each cell is 1- 

 ovuled ; but the rapid growth of one ovule soon destroys the other, and 

 the ovary becomes 1-celled, 1-seeded. The same thing occurs with 

 the Acorn, which is at first 3-celled, with 2 ovules in each cell. 



287. The Ovule, in its position in the cell, is 



Ascending when it rises obliquely, as in the Pellitory (Fig. 180, A) ; 

 Erect when it rises directly from the base : Groundsel (B) ; 

 Horizontal when at right angles with the axis ; Pea (C) ; 

 Pendulous when hanging from the upper part : Mezereon (D) ; 

 Suspended when hanging directly from the top: Mare's-tail (E). 

 In the Horse-chestnut there are two positions (F) ; one ovule is 

 erect, the other suspended. 



Fig. 181. — A, Ovule of Olax strictti. B, Lenma miTwr. C, Chelidonium 

 raphe; e, chalaza; A, hilum; /, funiculus; n, nucleus; h*, tegmen; te. 

 Wall-flower {CkeiraiUhui Cheiri). 



majvs; r, 

 testa. D, 



288. The position of the Ovule on His funiculus is very important. 

 It is Orthotropous, or straight (Gr. orthos, straight ; iropo, I turn), in 

 the Smartweed (Fig. 3, a) and Olax (Fig. 181, A) ; here the ovule has 

 the chalaza and hilum coincident (on the same line), with the mi- 

 cropyle opposite to them. The ovule is Anairopous, or inverted (Gr. 

 ana, up), in the Celandine (Fig. 181, C) ; here it is reversed on the 

 funiculus, which is prolonged into a stalk, the greater part of this 



