304 



ORGANOGRAPHY. 



fruits: — namely, the Legume, the Lomentum, the Drupe, and 

 the Utricle. 



1. Legume or Pod. — This is a superior, one-celled, one or 

 many-seeded fruit, dehiscing by both ventral and dorsal su- 

 tures, so as to form two valves, and bearing its seed or seeds on 

 the ventral suture. Examples occur in the Pea {fig. 654), Bean, 

 Clover, and most plants of the order Leguminosse, which has 

 derived its name from this circumstance. The legume assumes 

 a variety of forms, but it is generally more or less convex on its 

 two surfaces, and nearly straight ; at other times, however, it 

 becomes contorted so as to resemble a &cvew{fig. 677), or a 

 snail twisted, as in some species of Mcdicago {fig. 676), or coiled 

 up like a caterpillar, as in Scorpiurus sulcata {fig. 675), or curved 

 like a worm, as in Ccssalpinia coriaria, or it assumes a number 

 of other irregular forms. Certain deviations from the ordinary 

 structure of a legume are met with in some plants ; thus, in As- 

 tragalus {fig. 605), and Phaca {fig. 606), it is two-celled, in conse- 

 quence of the formation of a spurious dissepiment, which in the 

 first plant proceeds from the dorsal suture, in the latter from the 

 ventral. At other times a number of spurious horizontal dis- 

 sepiments are formed, by which the legume becomes divided into 

 as many cells as there are seeds, as in Cathartocarpus Fistula 

 {fig. 600). Another irregularity also occurs in the latter plant, 

 the legume being here indehiscent, but tlie two sutures are clearly 

 marked externally. Other indehiscent legumes are also met 

 with, as in Arachis and Pterocarpus, in which there is some- 

 times no evident mark of the sutures externally ; such legumes 

 will, however, frequently split into two valves like those of a pea, 



Fig. 675. 



Fig. 677. 



Fig. 678. 



^ 676.^ 



Fig. 675. Coiled-up legume of Scorpinrns sulcata. Fig. 676. Snail-like 



legume of Medicago orbiculaia. Fig. 677. Spiral or screw-like legume 



of Lucerne {Medicago). Fig. 678. Indehiscent lomentum of a species 



of Acacia. 



