ORGANS OF REPRODUCTION. 



49 



the most important points. The ovary consists of either 

 one entire piece like a bladder, or of two, three, four, 

 ■five, or more pieces united by their edges, the line of 

 union, or seam being called the suture, and the pieces 

 valves. An ovary so formed is called valved, and accord- 

 ing to the number of i^ieces, hi- valved, tri-valved, &c. 

 The interior consists of one chamber, or it is divided by 

 one or more partitions meeting in the centre (fig. 7, e), 

 being what are termed (in the fruit) dissepiments ; they 

 are either simple, straight, wavy, or branching and uniting 

 in various ways, forming equal or unequal cells called 

 loculi. Each cell contains one, two, or more ovules, and 

 whatever may be the character of the ovary or fruit as 

 regards the number of cells, or whether the cells contain 

 one or many ovules (even to several hundreds, as in the . 

 poppy), each ovule has a special attachment to somejj 

 part of the inside of the ovary, the point of attachmeni/ { 

 being called the placenta, which consists of a simple 

 point, or of thickened lines or ridges rising from the 

 internal surface of the ovary or partition, or of an 

 elevated disk or central column (fig. 7, c). These points, 

 lines, or columns have a direct connexion with the tube 

 of the pistil, through which by induction the ovules be- 

 come fertilized (see Fertilization). 



The attachment of the ovules to the placenta is more 

 readily seen as the fruit advances to maturity ; for ex- 

 ample, on opening a young pea-pod the ovules will be 

 /seen lying in a row on one side attached to a thickened \ 

 'cord (the placenta), which is the continuation of the '■ 

 footstalk terminating in the pointed apex of the pod, 

 originally the base of the pistil. 



In general, superior ovaries are sessile, but some are 

 elevated above the thalamus. In the passion-flower and 



E 



