242 



MORPHOLOGY OF THE ANGIOSPERMS 



gynoecia, and the inferior ovary. Under the theory of carpel poly- 

 morphism, bundles of much morphological significance in the re- 

 ceptacle tip were described as "discarded into the pith," 



The presence of sterile carpels united with fertile carpels has been 

 interpreted as representing a stage in the development of syncarpy 

 from apocarpy. This interpretation is obviously a misreading of the 

 process of evolutionary reduction. 



Fig. 92. Diagrams of cross sections of ovaries showing the structure of pseudo- 

 monomerous gynoecia derived from trimerous types. Dorsal bundles only shown in 

 A to G; ventral bundles only shown in H. Carpel limits shown by radial dotted lines. 

 A, Palmae, two placentae completely sterile, the third fertile on one side; B, Ponte- 

 deriaceae; C, Marantaceae (Thalia); D, Caryophyllaceae (Drypis), the placenta 

 between two carpels is completely sterile, the other two are fertile on one side 

 only; E, Chenopodiaceae (Beta), origin of the ovule trace is directly under the 

 median line of the fertile carpel; F, Gramineae, ovule borne on placenta between 

 two large carpels, attached to one of them; G, Anacardiaceae (Rhus); H, Berber- 

 idaceae (Nandina). (A to F, after Eckardt; G, from Payer; H, from Himmelbaur.) 



The "Solid" Carpel in Syncarpous Gynoecia. Where, in syncarpous 

 gynoecia, reduction in carpel number is in progress, the vestigial 

 carpels are sterile, commonly lack a locule, and are "solid" through 

 part or all their length. Abortive carpels are seen in a number of 

 families (Fig. 76). They are prominent in the ovaries of the Valeriana- 

 ceae, Berberidaceae, and Pontederiaceae, some of the Palmae {Cocos 

 and related genera), the Verbenaceae {Blairia), and the Caprifoliaceae 

 (Vihtirnum). The sterile carpels may be evident as mere ridges on the 

 sides of the ovary wall, as in Pontederia and Valeriana (Fig. 76D), but 

 may be fused into the ovary wall and evident only internally, as in 



