326 



THE FRUIT. 



name is strictly applicable only to fruits of this kind produced by 



the ripening of a single car- 

 pel ; as the plum, apricot, 

 peach (Fig. 447), &c. ; but 

 is extended in a general way 

 to all one-celled and one or 

 two-seeded fruits of similar 

 texture resulting from a com- 

 pound ovary, and even to 

 those of several bony cells in- 

 closed in pulp, as in the Dogwood (Fig. 240, b). The latter, how- 

 ever, are more strictly said to be drupaceous, or drupe-like fruits. 



605. An Achenium is a small and dry indehiscent one-seeded 

 pericarp, formed of a single carpel ; as in the Buttercup, and the 

 allied genera Anemone and Clematis, where they are often termi- 

 nated by the persistent and often plumose style, in the form of a 

 long tail. In the Rose (Fig. 684,) the achenia are borne on the 

 hollow expansion of the receptacle which lines the fleshy tube of 

 the calyx : in Calycanthus the achenia (Fig. 693) are similarly 

 inclosed in a sort of false pod (Fig. 691, 695) of the same nature 

 as the rose-hip, while in the Strawberry (Fig. 678, 679), they are 

 scattered on the surface of the enlarged and pulpy receptacle ; 

 where, as in many other cases, they are commonly mistaken for 

 seeds. But they are all furnished with styles, which show their 

 nature ; and on cutting them across we observe the real seed loose 

 in the cell. These seed-like fruits were incorrectly called naked 

 seeds by the earlier botanists. The strawberry, raspberry, &c., 

 therefore, taken as a whole, are not simple, but aggregate fruits. 

 In the Raspberry and Blackberry (Fig. 680), the achenia are 

 changed into little drupes (604). The name of achenia is also 

 applied to similar one-seeded fruits resulting from a one-celled 

 ovary, even when formed of more than one carpel, and invested by 

 the calyx-tube ; as that of the Sunflower and all Composite or 

 Syngenesious plants, where the limb of the calyx, assuming a va- 

 riety of unusual forms, is termed the Pappus (Fig. 776). 



606. A Cremocarp consists of a pair of achenia placed face to 

 face, and invested by the calyx-tube ; which, when ripe, sepa- 



FIG. 447. Vertical section of a peach. 448. An almond ; where the exocarp, the portion of 

 the pericarp that represents the pulp of the peach, remains thin and juiceless, and at length 

 separates by dehiscence from the endocarp, or shell. 



