THE LEGUME 123 



one or more nuts. The involucre may be dehiscent, as in the chestnut 

 and hickory-nut, or indehiscent, as in the black walnut (Fig. 345). In 

 some of its forms, the involucre of the glans tends to become fleshy. 

 Inasmuch, however, as the design of such pseudo-fleshy pericarps is 

 not that of subserving transportation by their food-properties, they are 

 more appropriately regarded as non-fleshy. While depending, like the 

 grasses, upon their gregarious habits for perpetuation, nut-yielding 

 plants are apparently in many cases distributed by the rounded form of 

 their coats and the readiness with which they are transported by flowing 

 water. 



The Nuca or Nut (Figs. 345, a, and 346, a). — The relationship of the 

 nut and its glans to the akene and its anthodium has already been 

 pointed out. The nut is in all cases much larger than the akene and its 

 pericarp commonly much thickened and very hard. 



The Spikelet (Fig. 347). — A fruit possessing a glumaceous involucre 

 and pertaining to the Gramineae (grass family) and related orders. 

 This class of fruits, like the glans and nut, connects those fruits which 

 are adapted to transportation with those which are not. Although, 

 in general, these plants depend for their perpetuation upon a highly 

 gregarious habit rather than upon provisions for distribution of their 

 fruits, yet the spikelets of some grasses are unmistakably so designed, 

 and are transported with their caryopses enclosed in the glumes. 



The Caryopsis or Grain (Fig. 348). — A seed-like fruit produced in a 

 spikelet, the ovarian wall and the seed-body closely adnate. 



The Follicle (Fig. 349). — A monocarpellary fruit dehiscing by one 

 suture only, this the ventral, except in rare cases. 



The Legume (Fig. 350). — A monocarpellary fruit, non-fleshy and 

 dehiscing by both ventral and dorsal sutures. Notwithstanding the 

 definition thus given, we have to record the fact that in accordance with 

 a different principle and construction, thte title includes all fruits of the 

 natural order Leguminosae. It, therefore, becomes necessary to point 

 out that the fruits of this family are extremely variable, and this in 

 directions which frequently carry them widely away from both the 

 structural and the physiological characters of the legume. The pecu- 

 liarities of the tamarind have already been pointed out. In the fruit 

 of the Inga the dehiscent legume is filled with a large amount of juicy, 

 edible pulp, in which the seeds are embedded. In other species this 

 pulp is replaced by one of a powdery consistency, while in others it is 

 fleshy or subcorneous. A great many legumes of this family are not 

 only indehiscent, but winged and one-seeded, and thus are true samaras. 



