47 



the Cherries, Mulberries, and some Maples, in summer ; but most 

 of them, like the Oaks, Chestnut, Pines, and others, in autumn. The 

 seeds of some species like the Willows die unless they germinate 

 soon after they mature. Most species retain their capacity to 

 germinate for several months or several years, while a few members 

 of the Pulse family are reported to retain their vitality for more 

 than 325 years. 



The mature fruit and seeds of our common trees show a wide 

 variation in their form and structure. Fruits are usually classified 

 on the basis of their texture, as fleshy fruits and dry fruits. Fleshy 

 fruits are represented by the fruits of such species as Cherries, 

 Papaw, Osage Orange, etc. (Plate X, 1, 2, 5, 7, 10). Dry fruits 

 are those which do not have any flesh or pulp, and are represented 

 by the fruits of such species as the Maples, Ashes, and Oaks (Plate 

 IX, 1-16, and Plate X, 3, 4, 6, 8, 9, 11, 12). Fleshy fruits including 

 the stone fruits, are indehiscent. Indehiscent fruits (Plate X, 1, 2, 

 5, 7, 10) are those which do not split apart regularly along certain 

 lines for the liberation of the seeds, while dehiscent fruits do split 

 open. Dry fruits may be indehiscent or dehiscent. 



The following general types of fruits are commonly recognized: 

 the pome (Plate XOII), the drupe (Plate X, 7, 10), the nut (Plate IX, 

 7, 8, 9, 14, 15), the samara (Plate X, 3, 6, 11), the follicle (Plates 

 LXXVI-LXXVIII), the capsule (Plate IX, 3, 5) and (Plate X, 9), 

 the legume (Plates XCIV-XCVII), the cone (Plate IX, 1) and the 

 collective or aggregate fruits, (Plate IX, 17). The species belonging 

 to a single genus usually produce a common type of fruit, but genera 

 belonging to the same family often have an entirely different kind 

 of fruit. This difference of fruit of genera in the same family is 

 shown very clearly in the Nettle family, to which belong the Elms, 

 Hackberry, Osage Orange, and Mulberry, whose fruit are shown on 

 Plate X, 3, 2, 1, and Plate IX, 17. A wide variation may also occur 

 within the general types mentioned above. The nut is one of the 

 commonest types of fruit found in the forest and will possibly 

 show this wide variation best. Nuts may be small and light, as in 

 the Buttonwood and Birches, or large and heavy as in the Oaks and 

 Chestnut. Light nuts often have appendages attached to them in 

 the form of a membranous wing or a tuft of hairs. The nuts may 

 be produced singly or in strobiles as in the Birches and Alder. 

 They may also be covered or naked. If covered, the covering may be 

 indehiscent and semi-fleshy (Plate IX, 7), or dehiscent and dry 

 (Plate IX, 8). It may also consist of a stalked prickly dehiscent 

 bur (Plate IX, 13), a large spiny dehiscent bur (Plate IX, 14), a 

 bladder-like bag (Plate IX, 10) or a leafy involucre, as in the Com- 

 mon Hazlenuts (Plate LI). In some species the seeds are not cov- 

 ered entirely but simply subtended by a leafy bract (Plate IX, 9). 



