222 MORPHOLOGY OF THE ANGIOSPERMS 



Definitions of these valve, solid, and semisolid types are difficult to 

 make, because the basis for each type was continually changed, as the 

 theory was extended, and the types are not distinct. The valve carpel 

 is described as open, commonly sterile — if fertile, with one or more 

 ovules on the lateral parts; the solid carpel, as "consolidated," colum- 

 nar, narrowed, usually fertile, with one or many ovules on the flanks; 

 the semisolid or "pseudovalve" as resembling the solid type but with 

 lateral wings, approaching in form the valve type. The interpretation of 

 structure of the simple, follicular carpel well illustrates the two basic 

 types: (1) a solid carpel, the dorsal part, with the midrib vascular 

 bundle and a narrow band of surrounding tissues — broad and winglike 

 in its semisolid variation; and (2) a valve carpel, the larger, ventral part, 

 with the ventral vascular supply and the sides of the carpel. No line of 

 demarcation between the carpels was described. 



The basis for the establishment of these types was anatomical. Each 

 vascular strand supplying the gynoecium or the individual carpel was 

 considered evidence of the presence of a carpel. The explanation of 

 the pair of bundles or a double bundle on the ventral side of many 

 carpels was that the bundle is split longitudinally, in preparation for 

 dehiscence along the suture. The number of vascular traces supplying a 

 gynoecium, apocarpous or syncarpous, was seen to indicate the number 

 of carpels present, and the origin of these traces at two levels indicated 

 two whorls of carpels. That the members of the "double trace" arose in 

 the receptacle at two points, often widely separated, was not considered. 



The polymorphism theory received very little support at any time 

 and was refuted from several viewpoints. It became prominent because 

 of the large amount of descriptive material published by its promoter 

 over a long period, and the ingenuity shown in the interpretation of the 

 gynoecia of many families under a theory that appeared fantastic to 

 many morphologists. It is valueless because, though its basis was an- 

 atomical, its interpretations of vascular structure were made without 

 regard to the basic vascular structure of the plant body. The funda- 

 mental error lay in the misinterpretation of stelar and trace structure in 

 the floral receptacle and of the vascularization of the carpels themselves. 

 Axis and appendages have a constant vascular relation at the node. If the 

 leaf were interpreted on the same basis as the carpel under the poly- 

 morphism theory, each leaf with three-trace vascular supply would 

 consist of two basic leaves, one a median "solid" leaf, and two lateral 

 wings, which, together, form a "valve" leaf. Aside from the anatomical 

 error, many inconsistencies rendered the morphological interpretations 

 unacceptable. 



The detailed descriptions of flower anatomy published as a basis 

 for this theory are apparently generally accurate and provide much 



