146 



MORPHOLOGY, OR COMPARATIVE ANATOMY. 



part of a multiple fruit, as in Ranunculus, Geum (fig. 289), c., where 

 they occur on a dry receptacle or thalamus, or as in the Strawberry, where 

 they occur imbedded in a succulent receptacle. Achaenia are popularly 

 mistaken for seeds, from which they may be known by the stylar beak 

 and by the seed lying loose inside. 



The term achaenium is often loosely applied to the halves of Umbel- 

 liferous fruits (fig. 300), the cocci of Mallows, the nucules or nuts of 

 Boraginacese, Labiatse, &c. (the carcerule of some authors) (fig. 282), and 

 to the cypsela of Composite (figs. 283-285). 



Fig. 283. 



Fig. 285. 



Fig. 284. 



Fig. 283. 



Cypsela of Scorzonera. Fig, 284. Cypsela of Bidens. 



Fig. 285. Cypsela sliced vertically, to show the seed within. 



Drupe. The Drupe is a one-celled fleshy fruit, represented 

 by stone-fruits formed from a single pistil, such as the Cherry or 

 Plum, where the stone is formed by the inner part of the pericarp, 

 and the pulp by the outer part. 



In common stone-fruits the drupe is solitary ; but minute drupes formed 

 on the same plan are assembled together on the receptacle of the Easp- 

 berry and Blackberry (fig. 290). The term drupe is often improperly 

 applied to the compound stone-fruits, like the Cocoa-nut, &c., or to the 

 Date, where the stone is formed by the seed alone, and the pulp by the 

 pericarp (fig. 280). Fruits of this general kind are called drupaceous. 



Follicle. The Follicle is a simple pod, splitting down the ven- 

 tral suture only, and bearing the numerous ovules on its margins. 



This rarely occurs solitary, but mostly combined with others in a circle, 

 as in Aquilegia, Sempervwum (fig. 281), &c. j and they are then often 

 coherent at the base. 



Legume. The Legume is a one- or many-seeded simple fruit, 

 usually splitting down both sutures, with the placentas on the 

 margins of the ventral suture. 



In most cases the legume is elongated and pod-like (fig. 286), as in the 

 Pea, &c. ; but sometimes it is curved or even spirally coiled like a snail's 

 shell, as in Medicago (fig. 287), or lobed and knotted, as in Acacia (fig. 288). 

 In Astragalus a spurious sutural septum is formed by projection inward 

 of one of the sutures (fig. 252). 



