I2I2 



A TEXTBOOK OF THEORETICAL BOTANY 



Fig. ii8o. — Vasculation of carpels in transverse section. Xylem in black. The 

 radial lines show the carpel boundaries. The marginal bundles of the in- 

 turned margins show reversed orientation. A, Eranthis hiemalis. B, Tulipa 

 gesneriana. C, AmigalUs arvensis. D, Melandyium dioicum. The last shows 

 a ring of axial bundles with normal orientation in the centre of the placenta. 

 (After Vati Tieghem.) 



Structure. The first type, called the " Valve Carpel ", is the one generally 

 recognized, and it is accepted by Saunders as a foliar type of organ. In 

 apocarpous gynoecia it is said to be the only type present and in such cases is 

 usually fertile. It bears only one style and one stigma. The second type, 

 the " Solid Carpel ", is present in most syncarpous gynoecia and in such 

 cases is said to be usually fertile while the valve carpels present are sterile. 

 The solid carpel is supposed to be reduced, in its most extreme form, to 

 no more than a vascular bundle, but it may also have a surrounding area of 

 ground tissue proper to itself. It may contain either one or two bundles, 

 with one or more corresponding rows of ovules. If there is a style it may be 

 either single or bifid. The third type is the " Semi-solid Carpel " or 

 Pseudo-valve, which combines some of the features of both the others. It 

 may have the lateral expansion of a valve carpel, but the ovules are not 

 borne marginally as in that type, but are borne on either side of the central 

 line. When a style is present, the twin dorsal bundles are both continued 

 upward into it and there is a bifid stigma. 



The standard example of a combination of solid and valve carpels is 

 said to be the gynoecium of the Cruciferae, in which the ovules are borne on 



