SUPPRESSION OR ABORTION. 273 



ornament of our vernal woods ; a complete and regular, but re- 

 markably unsymmetrical blossom, only two of the four circles 

 having the same number of members, and one of those (the sta- 

 mens) being abnormal in position. There are only two sepals: 

 within these are five petals : within and opposite these are five 

 stamens ; so that the primary stamineal circle is suppressed, and 

 those present belong to a second circle ; or, which is more likely, 

 as they cohere at the base with the claws of the petals, they may 

 arise from a chorisis of the petals themselves : and in the centre 

 there-are three pistils with their ovaries combined into one. Fur- 

 ther examples will illustrate those graver suppressions which render 

 the flower incomplete, and finally reduce it to a minimum. In 

 the Elm (Ord. UlmaceaB), the petals entirely disappear, and the 

 pistils are reduced to two, both of which are abortive in a part of 

 the flowers, and one always disappears in the fertile flowers dur- 

 ing the formation of the fruit. The occurrence of numerous cases 

 where parts that actually exist in the pistil at the time of flowering 

 are obliterated in the fruit, justifies the use of the term suppression 

 in the case of parts which, though requisite in the ideal plan, are 

 left out in the execution. Our Prickly Ash, as already stated 

 (472), not only wants one circle of floral envelopes altogether 

 (which, however, appear in the species of the Southern States), 

 but, being dioecious (474), the stamens also disappear in all the 

 flowers of one tree, while the pistils are all abortive in those of 

 another individual. In the Elite (Ord. Chenopodiacese), where the 

 plan is trimerous, the petals and two of the stamens are entirely 



o 



wanting ; as the annexed diagram (Fig. 340) shows. In the Cal- 

 litriche (Ord. Callitrichacese), where the plan is tetramerous, the 



FIG. 340. Diagram of the reduced flower of Blitum. 



FIG. 341. Diagram of a perfect flower of Callitriche, which has no floral envelopes, a single 

 stamen, and a four-celled pistil. 



FIG. 342. Diagram of the monoacious flowers of Euphorbia : a, the pistillate flower, reduced 

 to a mere three-celled pistil; and b, one of the staminate flowers reduced to a single stamen. 



FIG. 343. Diagram of the dioecious flowers of the Willow : a, one of the pistillate flowers 

 reduced to a solitary pistil ; 6, a staminate flower reduced to a pair of stamens. 



