8 



EXAMINATION OF 



[CHAP. 



is somewhat pointed, ending in a loose, cellular tip. This 

 cellular surface is termed the stigma. It is invariably 

 present. The lower portion of the carpel, containing the 

 ovule, is the ovary. The stigma is very shortly stalked 

 in the buttercup. In many plants the stalk of the stigma 

 is of considerable length, sometimes several inches ; 

 whether long or short, however, it is called a style. If 

 there be no style, the stigma is sessile. 



The structure of all the carpels of the buttercup is iden- 

 tical : they each contain one ovule, and are each provided 

 with a stigma, and a very short style. 



The carpels, taken together, constitute the pistil j they 

 are the fourth and last series of the flower-leaves, and 

 occupy the centre of the flower and, consequently, the 

 extremity of the stem. As the parts of the pistil in the 

 buttercup are wholly free from the calyx, the pistil is 

 termed superior, and as the carpels which compose it are 

 free from each other the pistil is apocarpous. 



9. Gather now another specimen of the buttercup : one 

 in a more advanced state, with the sepals, petals, and 

 stamens of some of its flowers all fallen away, and only 



FIG. 6. Longitudinal 

 section of a fruit- 

 carpel (acttene) of 

 Buttercup, contain- 

 ing one seed. 



FIG. 7. Longitudiial 

 section of a seed of 

 Buttercup, showing 

 the minute embryo 

 at the base of the 

 albumen. 



the heads of carpels (pistils) remaining. The pistil here 

 is passing into fruit. The carpels remain distinct from 

 each other as at first, but they have enlarged and hard- 

 ened ; the stigmatic apex has dried up, so that the top 

 of each carpel is simply pointed or slightly hooked. Open- 



