THE OVULES. 



49 



ovule is solitary y in Umbelliferge it is also solitary in each of the 

 two carpels ; in the Pea order they are definite, being but few ; 

 in Mullein and Poppy, indefinite ( OO ), too many to be readily 

 counted. As to position, the ovule is erect when it grows up- 

 ward from the base of the cell, as in Composite; ascending, 

 when it turns upward from the side of the cell ; horizontal, when 

 neither turning upward nor downward ; pendulous, when turned 

 downward; and suspended, when growing directly downward 

 from the top of the cell, as in Birch (158-161). 



150 



150, Pistil of Celosia: the pericarp detached, showing the young ovules. 151, Flower of Rlmbarb, 



pericarp reuw>ved, showing the young ovule. 152, A similar ovule (orthotropous) of Polygonum. 153, 

 The same, full grown ; foramen at top. 154, Section showing its two coats, nucleus, and sac. 155, Ana- 

 tropous ovule, as of Columbine; , foramen. 156, Section of same. 157, Campylotropous ovule, as of 

 Bean; <i, foramen. 158, Section of a Cherry; ovule anatropous, suspended. 159, Section of carpel of 



Ranunculus; ovule ascending. 160, Senecio; ovule erect. 161, Hippuris; ovule pendulous. 



140. 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 faniculus ; the point of its juncture with the 

 base of the nucleus is the chalaza. The nucleus was first formed ; 

 then the tegmen, 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 orifice, 

 the foramen. 



141. 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 



tists, and it stands straight, as in the Buckwheat order, it is 



4 



