228 



MORPHOLOGY OF THE ANGIOSPERMS 



carpels — especially Degeneria — show a simple closing by folding; the 

 conduplicate carpel so formed has the ventral surfaces of the lamina 

 halves in contact, with the edges side by side. The frequent occurrence 

 of the conduplicate type in primitive taxa and its simplicity have been 



Fig. 87. Cross sections of carpel at various stages of development to show marginal 

 meristems. I to III, Anemone silvestris: I, II, sections of very young carpel, proximal 

 and distal, respectively; III, part of I, showing by shading the cells derived from 

 the marginal initial. IV to VIII, A. Pulsatilla: IV, V, sections of young carpel, proxi- 

 mal and distal, respectively; VI to VIII, sections of carpel with marginal growth 

 completed, mi, marginal initial. ( After Sprotte. ) 



considered evidence that all other types have been derived from this 

 by reduction of the marginal strips and a withdrawal of the edges, to- 

 gether with the ventral, half-inverted, placental bundles. But carpels 

 with edges and margins deeply inrolled are complex and seem not to 

 have been derived from the conduplicate type. The carpels of some 

 taxa seem to close edge to edge; in others, the margins are inrolled 



