CLASSIFICA.TION OF FRUITS. 



55 



thickened and entirely distinct from the 

 enclosed seed. The akene varies in many 

 directions toward other fruits. In many 

 cases the pericarp is inclined to be fleshy 

 and in a few it tends toward dehiscence, 

 thus simulating a follicle. Some forms of 

 the akene are distinctly winged, so that 

 they might but for the relationship of the 

 species yielding them to akene producing 

 species be with equal propriety classed 

 as samaras. They are in nearly all cases 

 provided with some means for securing 

 wind transportation or for attaching them- 

 selves to passing bodies, and yet there are 

 numerous cases in which all such appen- 

 dages have become entirely obsolete. For 

 these reasons it becomes a matter of ex- 

 treme difficulty to frame a definitiDU at 

 once comprehensive and delimiting for 

 this group. The inferior akene is some- 

 times distinguished by the term Cypsela 



(Figs. 61 to 67). 



Note should here be takenof the fact that 

 the latter is characteristic of that largest 

 of all families, the Compositae, in which 

 the akenes of the head are massed and 

 partially, or sometimes completely, sur- 

 rounded and enclosed by an involucre, the 

 whole constituting a multiple fruit to 

 which the name Hypanthodium (Fig. 295) 

 has been applied. The Hypanthodium 

 varies greatly in its characters. Although 

 usually multiflorate, it is commonly few, 



flowered. In 



or even \n rare cases 

 those cases in which the involucre com- 

 pletely encloses the achenia it is commonly 

 appendaged for distribution in an entire 

 condition, as in the burdock. This condi- 

 tion connects the Hypanthodium with the 

 glans and the contained achenia with the 

 nut. Indeed, it is almost impossible to 

 distinguish structurally between the fruitf 

 of the Xanthium and that of the Fagus, 



The Glans (Fig. 297 and 298).— A fruit 

 consisting of an accrescent and partially 

 or (commonly completely) enclosing in- 

 volucre containing one or more nuts. The 

 involucre may be dehiscent as in the chest- 

 nut and hickory nut, or indehiscent, as in 

 the Brazil nut and black walnut. In some 

 of its forms, moreover, the involucre of 

 the glans tends to become fleshy. Inas- 

 much, however, as the design of such 

 pseudo-fleshy pericarps is not that of sub- 



erties, they are more appropriately re- 

 garded as non-fleshy. While depending 

 like the grasses upon their gregarious hab- 

 its for perpetuation, nut-yielding plants 

 apparently in many cases are distributed 

 by the rounded form of their coats and 

 the readiness with which they are trans- 

 ported by flowing water. 



TheNuca or Nut (Figs. 297 and 298 a) 

 The relationship of the nut and its glans to 

 the akene and its hypanthodium has al- 

 ready 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. 299).— A fruit posess- 

 ing a glumaceous involucre and pertaining 

 to the Gramineae (grass family) and re- 

 lated 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 un- 

 mistakably so designed, and are trans- 

 ported with the caryopsis enclosed in 



the glumes. 



The Caryopsis or Grain (Fig. 299 A) —A 

 seedlike fruit produced in a spikelet, the 

 ovarian wall and the seed coats closely 



adnate. 

 The Follicle (Fig. 300).— A monocar- 



pellary fruit dehiscing by one suture only, 

 except in rare cases the ventral. 



The Legume (Fig. 301).— A monocarpel- 

 lary fruit, non-fleshy and dehiscing by 

 both ventral and dorsal sutures. Not* 

 withstanding the definition thus given, 

 we have to record the fact that in accord- 

 ance with a different principle and con- 

 struction, the title includes all fruita of 

 the natural order Leguminosae. It there- 

 fore becomes necessary to point out t}iat 

 the fruits of this family are extremely 

 variable, and this in directions which fre- 

 quently carry them widely away fr:^m the 

 structural characters of the legume, "J-ho 

 peculiarities 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 pulp, in which the seeds 

 are embedded. In other species this pulp 



serving transportation by their food prop- Is replaced by one of a powdery cousis- 



