THE CARPEL 



241 



sterile carpel or carpels may be evident in external form as super- 

 numerary styles (Fig. 91) or external ridges; they may be apparent in 

 cross sections of the ovary, sometimes as obvious sterile units, as in 

 Pontederia ( Fig. 92B ) ; sometimes as solid carpels, as in Valeriana ( Fig. 

 76D), Cocos (Fig. 93), and related taxa. Where, in pseudomonomerous 

 gynoecia, the style of a sterile carpel persists, it is sometimes shorter 

 than that of the fertile carpel — Celtis, Moms — but may be of the same 



Fig. 91. Diagrams of lateral and cross sections of pseudomonomerous gynoecia, con- 

 sisting of two carpels: one fertile, with ovules, and the other "solid," sterile, without 

 locule. A, B, Moms alba; C, D, Ulmtis montana; E, Celtis occidcntalis. df, dorsal 

 bundle of fertile carpel; ds, dorsal bimdle of sterile carpel; /), petal bundle; s, 

 stamen bundle; vf, ventral bundle of fertile carpel; vs, ventral bundle of sterile 

 carpel. (A to D, after Eckardt; E, after Bechtel.) 



length and may be even longer and take on the function of pollen re- 

 ception. Sometimes the abortive carpel is represented only by a vascular 

 bundle in the ovary wall. In tlie receptacle, evidence of carpels that 

 have disappeared externally — seen as mere traces that end blindly — ^is 

 occasional. But the interpretation of "blind" bundles in the receptacle 

 tip is difficult, because they may be vestigial tips of stelar bundles ex- 

 tending beyond the uppermost carpellary traces, or they may be traces 

 of lost carpels. Evidence of the nature of these carpels can be deter- 

 mined by number, origin, and position in relation to carpel traces below 

 them. Misinterpretation of vascular bundles in the receptacle tip has 

 been responsible for errors in understanding the morphology of carpels, 



