GROUP V. ANGIOSPERM/E. 



473 



The following varieties of true fruits have been distinguished by the 

 character of the pericarp, whether it is dry or succulent, hard or soft. 

 and by the dehiscence or indehiscence of the pericarp. 



A. DRY FRUITS. The pericarp is woody or coriaceous ; when ripe, the 

 sap has usually disappeared from all the cells. 



I. Dry Jndehiscent Fruits. The pericarp does not rupture, but encloses 

 the seed until germination; the testa is usually thin, and frequently coa- 

 lescent with the pericarp. 



(1) One-seeded fruits : 



(a) The nut (glans), e.g. Acorn, Hazel-Nut (but not the Walnut) ; the 

 dry pericarp is hard and sclerenchymatous : it is inferior and 

 syncarpous. 



(b) The aakene is superior and monome- 

 rous : the pericarp is thin and cori- 

 aceous ; e.g. the Rose and the But- 

 tercup. The similar fruit of the 

 Compos itse is a cypsela 5 it is in- 

 ferior and dimerous. 



The fruit of Grasses, termed a 

 caryopsis, is very similar to the 

 achene; it differs from it in that 

 the testa and the pericarp closely 

 adhere, whereas in the achene they 

 are not adherent. 



(2) Many-sseled fruits: these (schizocarpn) 

 commonly split into one-seeded fruits, which 

 usually enclose the solitary seeds until germin- 

 ation: e.g. the Umbelliferse (Fig. 287) and Maple, 

 with two, the Euphorbiacese with three, meri- 

 carps ; the Geraniacese, with five mericarps ; 

 and most Malvaceae, where the fruit is termed 

 a carcerule, and splits into many mericarps. 



The pericarp of dry indehiscent fruits is 

 sometimes developed into a membranous wing 

 (e.g. Ash, Elm, Birch) ; to such a fruit the term 

 samara is applied : the fruit of the Maple is a 

 double samara. 



II. Dry Dehiscent Fruit*. The pericarp rup- 

 tures and allows the seeds, which usually have a firm and thick testa, to 

 escape: they are commonly many-seeded. 



(1) Dehiscence longitudinal. 



(a) The follicle, consisting of a single carpel which dehisces along 



the ventral suture, where also the seeds are borne, e.g. Pseonia 

 and Illicium (Fig. 288) ; but sometimes (e.g. Magnolia) along 

 the dorsal suture : it is superior. 



(b) The legume or pod likewise consists of but one carpel which 



dehisces along buth the dorsal and ventral sutures (Fig. 288 A, 

 "transverse section Fig. 282 A) : e.g. the Vetch, Pea, Bean, and 



FIG. 287.-C<zrum Carut. 

 one of the Umbellifersp. A 

 Ovary of the flower (/). 

 B Ripe schizocarp which 

 has divided into two cocci 

 or mericarps (m), a portion 

 of the median wall (a) forms 

 the carpophore. 



