ITS STRUCTURE AND TRANSFORMATIONS. 287 



carpel across its cell (Fig. 539-541) ; and the solitary carpel 

 is similarly divided lengthwise in many species of Astragalus. 

 as in Fig. 534. Transverse divisions or constrictions across 



o 



a maturing ovaiy (such as is seen in Fig. 620) are not uncom- 

 mon, especially in legumes and other pods, and are of little mor- 

 phological significance. 



538. External Accessions may here be referred to. The wing 

 of the pericarp in Maple, Ash, and the like (Fig. 625-G27) , are 

 familiar instances of this ; and of the same nature are the im- 

 bricated scales which cover some Palm-fruits ; the prickles on 

 the pod of Datura, Ricinus, &c., and the hooked or barbed 

 prickles of many small pericarps (as in various Borraginaceae) , 

 which thus become burs and are disseminated by adhering to the 

 hairy coat of cattle. All these are of the nature of superficial 

 outgrowths, and these especially affect the pericarp or parts 

 connected with it. 



539. Persistence of Connected Organs. An adnate calyx (331 ) , 

 being consolidated with the ovaiy, necessarily makes a constit- 

 uent part of the fruit, in the pome (575) doubtless a very large 

 part. The limb or lobes of such adnate organ may persist, as 

 the tips of the sepals on an apple or quince, and may be turned 

 to useful account, as is the pappus of Composite for dissemina- 

 tion. Or, in small pericarps, the style may persist as part of the 

 fruit, and subserve the same ends, either by becoming feathery 

 for aerial dissemination, as in Clematis and in one section of 

 Geum, or by becoming hooked at the tip for adhesion to fleece, 

 &c., as in other species of the latter genus. Or adjacent parts 

 which are not actually incorporated with the pericarp may play 

 similar parts in the economy, as the hooks on the calyx-tube of 

 the dry calyx of Agrimonia, which at maturity is detached with 

 the included fruit, the fleshy fructiferous calyx of Gaultheria (Fig. 

 651) and of Mulberry (Fig. 654) ; and the pulpy fructiferous re- 

 ceptacle of the strawberry (Fig. 653) : the ultimate utilities in 

 both classes of instances being similar, viz., wide dispersion of 

 the seed by animals, whether by external carriage, or by being 

 devoured and the voided seeds of fleshy fruits thus disseminated. 



540. Transformations in Consistence. In the change from 

 ovaiy to mature pericarp, various kinds of transformations may 

 take place. In some the wall of the ovary remains thin and 

 becomes in fruit foliaceous or leaf-like, as in a pea-pod, the 

 carpels of Columbine, and Marsh Marigold (Caltha), or the pod 

 of Colutea or Bladder Senna. In others it thickens and becomes 

 at maturit}' either dry throughout, as in nuts and capsules ; or 

 fleshy or pulpy throughout, as in berries ; or hard-rinded with- 



