INTRODUCTORY LESSONS. XXV11 



the pistil, it is Introrse (Figs. 68, 71, 72, 73); and when it faces away 

 from the pistil, it is Extrorse (Fig. 69). 



The Pistil grows upou tbe receptacle, or upon a stem arising 

 from it, called a Stipe (Fig. 71). In a few orders there are several or 

 many pistils in each flower. Usually there is but one, formed of several 

 simple pistils (carpels) united more or less closely. As in the other floral 

 organs, there are all degrees of cohesion, from a slight union of the 

 bases of the ovaries rarely of the stigmas only to such completeness 

 as leaves no trace of lobes in the stigma (see Fig. on p. 5). Often the 

 free styles tell how many carpels compose the pistil (Fig. 69). Generally 

 the stigmas are divided or lobed (Fig. 68). These marks wanting a cross 

 section of the ovary, or, better still, of the partly grown fruit, will usu- 

 ally show a cell for each carpel (see the right-hand figure, p. 88b). If 

 the ovules (or young seeds) are in the center or grow on more than one 

 side of the ovary (or pod), the pistil is compound. A simple pistil is 

 generally plainly one-sided. A symmetrical pistil is compound. 



Inferior Ovaries. When the calyx adheres to the ovary, so as 

 to form, after the ovary has matured, the outer part of the fruit, it is 

 said to he superior, because the apparent catyx, its lobes, or cup, seem 

 to grow upon the ovary. For the same reason the ovary is said to be in- 

 ferior (Figs. 68, 72). There are all degrees of adhesion, from the slight 

 union at the base, as seen in Whipplea (Fig. 73), to the remarkable ex- 

 treme exhibited in the plant figured on p. 5, in which not only the ovary, 

 but several inches of the style, is adherent to the calyx. When the 

 adhesion is only partial, it can be shown by cutting the flower vertically, 

 as represented in Fig. 73. 



The Fruit is the ripened ovary (or set of ovaries), and all that 

 directly belongs to it. A dry fruit which opens in any way to let out the 

 seeds is called a Pod, A pod formed by the growth of a simple pistil 

 (one-carpeled) is called a Follicle when it splits only along the side which 

 bears the seeds. A Legume splits down both edges. Pods formed of 

 several carpels are called Capsules. Akenes are dry, indehiscent, seed- 

 like fruits, containing but one seed. Utricles are distinguished from 

 akenes by their thin coats, which are too large for the inclosed seed. 



