THE OVULES. 



109 



415 



416 



417 



410 



406, Pistil of Celosia, the pericarp detached showing the young ovnles. 413, Flower of Rhu- 

 barb ; pericarp removed showing the young ovule. 407, A similar ovule (orthotropous) of 

 Polygon nun. 403, The same, full grown ; foramen at top. 409, Section showing its two 

 coats, nucleus and sac. 410, Anatropous ovule, as of columbine; a, foramen. 411, Section of 

 same. 412, Campylotropous ovule, as of Bean ; a, foramen. 414, Section of a cherry, ovule 

 anatropous, suspended. 415, Section of carpel of Banunculus; ovule ascending. 416, Senecio ; 

 ovule erect. 417, Hippuris; ovule pendulous. 



533. THE NUMBER of ovules in the ovary varies from one to hun- 

 dreds. Thus in buttercups, Composite and grasses the ovule is solitary; 

 in Umbeliferse it is also solitary in each of the two carpels ; in the Pea 

 Order they are definite, being but few ; in Mullein, Poppy, indefinite^ o>), 

 too many to be readily counted. 



534. THE POSITION of the ovule in the cell is defined by certain 

 terms as follows; erect, when it grows upwards from the base of the 

 cell, as in Composite ; ascending, when it turns upwards from its point 

 of lateral attachment; horizontal, when neither turning upwards nor 

 downwards ; pendulous, when turned downwards, and suspended, when 

 growing directly downwards from the top of the cell, as in birch. (315, 

 316, 317, 319). 



535. THE OVULE AT THE TIME OF FLOWERING is soft and pulpy, 

 consisting of a nucleus within two coats, supported on a stalk. The 

 stalk is called funiculus ; the point of its juncture with the base of the 

 nucleus is the chalaza. The nucleus was first formed, then the legmen 

 or inner coat grew up from the chalaza and covered it, and lastly the 

 outer coat, the testa, invested the whole. Both coats remain open at 

 the top by a small passage, the micropyle. 



536. CHANGE OF POSITION. In most cases the ovule, in the course 

 of its growth, changes position, curving over in various degrees upon its 

 lengthening funiculus or upon itself. When no such curvature exists, 

 and it stands straight, as in the buckwheat order, it is orthotropous. It is 



