290 THE FLOWER. 



the figure last cited, and in Fig. 491, 495, &c., one row belonging to 

 eacli margin of the leaf. A simple pistil, accordingly, can have 

 only one placenta ; but that is structurally double. 



545. So a single pistil can have only one style and one stigma. 

 But as the stigma answers to the margins of the apex of the leaf, 

 this must also be double in its nature. And this is evidently the 

 case in the Peony and Isopyrum (Fig. 491), in the Tulip, as well 

 as in Fig. 493 - 495, and in almost all cases in which the stigma 

 extends down the inner face of the style, as it frequently does. 

 Such unilateral stigmas we accordingly take to be the typical form ; 

 and say that, while the united margins of the transformed leaf which 

 compose the ventral suture are turned inwards into the cell of the 

 ovary to hear the ovules, in the simple style they are exposed external- 

 ly to form the stigma. Where the stigma is terminal, or occupies 

 only the apex of the style, we suppose that these margins are in- 

 folded in the style also, and form in its interior the loose conducting 

 tissue through which a communication is established between the 

 stigma and the interior of the ovary. 



546. The ovary of a simple pistil obviously can have but one 

 cavity or cell ; except from some condition out of the natural order 

 of things. But the converse does not hold true : all pistils of a sin- 

 gle cell are not simple. Many compound pistils are one-celled, as 

 will presently be explained. 



547. A leaf or member of the gynsecium then, when separate, 

 forms a simple pistil ; when combined with others, it makes part of a 

 compound pistil. It is convenient to have a name which shall desig- 



* nate a single pistil-leaf, whether occurring as a distinct simple pistil, 

 or as an element of a compound pistil. For this purpose the name 

 of Carpel has been devised. A carpel is either a simple pistil, 

 or is one of a circle of leaves which compose a compound jMstil. 

 When the pistils are distinct from each other, they are said to be 

 apocarpous ; when united into one body, syncarpous. This union 

 produces a 



548. Compound Pistil. All degrees of union of the carpels may 

 be observed, from the coalescence of the lower part of their ovaries, 

 their summits remaining separate (as in Fig. 496), or from the com- 

 plete union of the ovaries into one body, the styles remaining sepa- 

 rate (as in Fig. 497), to the complete coalescence of the styles also 

 (Fig. 498), and even of the stigmas (Fig. 499), into one body. It is 

 evidently the same as if two or more pistils (in Fig. 497 - 499, tliree 



