436 



THE ROSALES 



The senna family has essentially the same type of flower as 

 the plum save that the pistil usuall}' contains many seeds (nor- 

 mally but one develops in the plum) and splits at maturity into 

 two valves, a form of fruit called a pod. For example, in the 

 honey locust (Gleditsia) and the Kentucky coffee bean (Gymno- 

 cladiis), the receptacle forms a shallow cup which bears the 

 regular sepals, petals and usually ten stamens about a single 

 pistil (Fig. 315, A). The flowers are really monoecious, but in 



Fig. 314. Flowers and fruits of the apple and plum families: A, inflor- 

 escence of the apple {Malus). B, section of flower, showing adhesion of 

 receptacle to the ovary, epigynous flower. C, sections of the fruit — c, car- 

 pels of the pistil; r, fleshy receptacle. D, flower of cherry (Prunus). E, 

 section of flower — r, cup-like receptacle which falls ofif as fruit matures. F, 

 fruit in section, showing the outer part of the wall of the ovary as a fleshy 

 rind and the inner part forming the stone or pit which enclosed a single seed. 



other respects are very suggestive of the plum flower. In the cof- 

 fee bean tree, however, the petals are not quite equal and this ir- 

 regularity becomes more noticeable in the sensitive pea (Cassia) 

 (Fig. 315, B~D). In the redbud, or Judas tree (Cercis), the 

 petals are very irregular, two of them being united into a boat- 

 like structure, known as the keel, which encloses the ten dis- 

 tinct stamens and single pistil, while two laterally placed petals, 



