DEHISCENT APOCARPOUS FRUITS. 



263 



Magnolias, Banksias, and Liriodendron (fig. 306). Occasionally in 

 Magnolia grandiflora, some of the follicles open by the dorsal suture. 



548. The Legume or Pod (legumen, pulse) is a solitary, simple, ma- 

 ture carpel, dehiscing by the ventral and dorsal suture, and bearing 

 seeds on the former. It characterizes leguminous plants, and is seen 

 in the Bean and Pea (fig. 469). In the Bladder-senna (fig. 470) 

 it retains its leaf-like appearance, and forms an inflated legume. In 

 some Leguminosse, as Arachis, the fruit must be considered a legume, 

 although it does not dehisce. In place of opening at the sutures, some 

 legumes are contracted at intervals, so as to include each seed in a 



separate cell, and when ripe, the different divisions of the pod separate 

 from each other. This constitutes theLomentum(lomentum, bean-meal), 

 or lomentaceous legume of Hedysarum coronarium (fig. 460), Coronillas, 

 Ornithopus, &c. In Medicago, the legume is twisted like a snail (fig. 

 471), and in Csesalpinia coriaria, or Divi-divi, it is vermiform or curved 

 like a worm ; in Carmichaelia, the valves give way close to the suture, 

 and separate from it, leaving a division. 



549. Syncarpous Fruits are formed by several carpels, which are 



Fig. 469. Legume of Pisum sativum, common Pea, opened. It is formed by a single carpel, 

 and dehisces by the ventral and dorsal suture, v v. Valves formed by the two parts of thi 

 pericarp, p, The epicarp or external layer of the pericarp, f/, Endocarp or internal layer. 

 Between these the mesocarp is situated g, Seeds placed one over the other, attached to the 

 placenta by short funiculi or cords, //. The placenta forms a narrow line along the ventral 

 suture, v. s d, The dorsal suture corresponding to the midrib of the carpellary leaf. 



Fig. 470. Legume of Bladder-senna (C'olutea arbor escens), showing an inflated, foliaceous 

 pericarp. 



Fig. 47L Twisted or spiral legume of Medicago. 



