122 



CLASSIFICATION OF FRUITS 



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-trans- 

 portation or for attaching themselves to passing bodies, and yet there 

 are numerous cases in which such appendages have become entirely 

 obsolete. For these reasons, it becomes a matter of extreme difficulty 

 to frame a definition at once comprehensive and delimiting fpr this 

 group. The inferior akene is sometimes distinguished bj^ the term 

 Cypsela (Figs. 74 to 80). 



Fig. 339. Samara of ash. 340. Of maple. 341. Utricle. 342. Several winged samara of Mascaffraia. 

 343. Vertical section of anthodium. 344. Vertical section of akene of buttercup. 345. Same of the 

 glans of black walnut. 346. Glans of Fagus, or beech-nut. 



Note should here be taken of the fact that the latter is characteristic 

 of the largest of all families, the Compositae, in which the akenes of 

 the head are massed and partially, or sometimes completely, surrounded 

 and enclosed by an involucre, the whole constituting a multiple fruit to 

 which the name Anthodium (Fig. 343) has been applied. The anthodium 

 varies greatly in its character. Although usually many-flowered, it is 

 commonly few-, or even in rare cases, one-flowered. In those cases in 

 which the involucre completely encloses the akenes, it is commonly 

 appendaged for distribution in an entire condition, as in the burdock. 

 This condition connects the anthodium with the glans and the contained 

 achenium with the nut. Indeed, it is almost impossible to distinguish 

 structurally between fruits representing these two classes, as, for instance, 

 those of Xanthium and Fagus. 



The Glans (Figs. 345 and 346). — A fruit consisting of an accrescent 

 and partially or (commonly) completely enclosing involucre containing 



