280 



STRUCTURE OP OVARIUM, PISTIL, ETC. 



extremity, termed pores, as at c ; and sometimes by valves, as 

 at d. These different methods are characteristic of different 

 tribes of Flowering plants. 



434. Now the portion of the reproductive system in the 

 Phanerogamia, to which nothing analogous exists in the lower 

 tribes, is that which is denominated the ovarium or seed-vessel ; 

 this occupies the centre of the flower, being sometimes situated 

 above, and sometimes apparently below, the point at which the 

 leafy parts of the flower arise from the axis which bears them. 

 This ovarium is the part, in which are formed the ovules or 

 young seeds ; and these, after being fertilised in the manner 

 presently to be described, ripen into the perfect seeds. Some- 

 times it consists of several evident divisions ; in other instances, 

 these are united together, more or less closely ; and all mark of a 

 division may even disappear. The ad- 

 joining figure represents the centre of 

 a flower, in which the several parts of 

 the ovarium remain separated ; three 

 only are seen, the others being con- 

 cealed by them. These separate parts 

 are termed carpels. Each carpel is 

 surmounted by a sort of pillar, termed 

 the style; which usually expands at 

 its summit, into a fleshy surface called 

 the stigma. When the carpels adhere 

 closely together, their styles also fre- 

 quently unite, so as to form a single 

 pillar ; which sometimes, however, di- 

 vides again into several branches at the 

 top. The ovarium, with its style and 

 stigma, is then called the pistil; and sometimes each separate 

 carpel, with its own style and stigma, receives the same appel- 

 lation. An excellent illustration of an ovarium consisting of 

 many carpels, appearing externally single, but each really sepa- 

 rate from the rest, is the Orange ; the juicy part of which fruit 

 is the ovarium, composed of a number of carpels adhering to- 

 gether, but not so closely united as to prevent their being torn 



FIG. 81. PISTIL OF CORIARIA 

 MYRTIFOLIA, showing distinct 

 carpels and styles. 



