160 M. Walpers on the Irregular Form 



will at all events adopt that position in which it meets with 

 the least opposition ; it will consequently approach the upper 

 floral pole, where the other four abortive ovaries would have 

 stood — an appearance which, although in a slight degree, we 

 also find in the true Papilionacece — by which the reciprocal 

 pressure of the individual floral parts on one another becomes 

 more equalized. The irregularity of the flower diminishes 

 however in the proportion in which this equality is established. 

 The calyx in this case is nearly regular {Hymenaea, &c.), and 

 just so the corolla dependent on it ; although frequently, as a 

 sign of the still perceptible eccentricity of the ovarium, a 

 slight irregularity of the floral parts is evident. 



If lastly the calyx is indeed gamosepalous tubular, but if the 

 petals are provided with claws which exceed the calycinal tube 

 in length, or if they cohere with it in their whole length, both 

 which cases are of frequent occurrence in the Mimosea, then 

 all reason for irregularity of the corolla disappears of itself, the 

 corolla as well as the calyx are regularly quinquepartite or 

 expanded rosaceously, and since the petals are then constantly 

 acuminate, they can no longer cover one another laterally in 

 the bud, but are merely folded valvately {(sstivatio valvata). 

 The stamina here frequently occur in very considerable num- 

 ber, and then, in consequence of the increased pressure by the 

 inferiorly narrow calycinal tube, frequently cohere inter se, al- 

 though above the tube they are perfectly free. At the same 

 time the calycinal tube is here so narrow that there can no 

 longer be a question as to a sensible eccentricity of the ova- 

 rium ; and the influence which this would exert on the form 

 of the corolla seems to be thus suspended, from the ovarium 

 being frequently provided with a considerably long stipes, 

 which appears to destroy the reaction against the unilateral 

 pressure of the calyx, since it is but feeble. In this group we 

 find the case, already frequently mentioned, of a pentagynous 

 leguminous plant, which we have considered of such im- 

 portance in explanation of the papilionaceous flower. 



