THE CARPEL 



191 



Conduplicate and Involute Closure. The closing of the carpel comes 

 about, structurally, by an upturning of the sides of the lamina and the 

 bringing together adaxially of the surfaces or edges, with more or less 

 complete fusion. (Recent description of abaxial folding in Cercidiphijl- 

 lum was based on the error of interpretation of the inflorescence as a 

 flower.) The upturning may be a simple folding on the midrib region 

 as an axis, with the margins lying side by side (Fig. 74A), or it may be 



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Fig. 74. Semidiagrammatic sketches of cross sections of carpels to show two methods 

 of closure of carpels. A, conduplicate method, borders of the lamina meeting face 

 to face by ventral surface, vascular bundles half-inverted; B, involute method, 

 margin of lamina meeting margin (marginal initials meet), vascular bundles in- 

 verted; C, involute method, borclers of the lamina meeting by their dorsal surfaces, 

 margins free. 



a more or less extensive incurving or inrolling, with contact face to 

 face by the edges (Fig. 74B) or, where the inrolling is strong, by parts 

 of the abaxial surface, with the margins free within the locule (Fig. 

 74C). The carpel has apparently closed independently in many lines 

 and in a variety of ways. A primitive method of closing is that of a 

 simple folding so that considerable parts of the adaxial surface come 

 together; a carpel, closed in this way, is called conduplicate (Fig. 74A). 

 Conduplicate closing has been considered the basic type from which 

 all others have been derived, but a survey of many families sug- 

 gests that this method is only part of the history of carpel closure. 

 Carpels in which the lamina sides appear rolled upward and inward 



