LESSON 20.] 



ITS KINDS. 



131 



353. A Samara, or Key-fruit, is either a nut or an achenium, or any 

 other indehiscent fruit, furnished with a wing, like that of the Mapls 

 (Fig. 1), Ash (Fig. 300), and Elm (Fig. 301). 



354. The Capsule, or Pod, is the general name for dry seed-vessels 

 which split or burst open at maturity. 



But several sorts of pod are distin- 

 guished by particular names. Two of 

 them belong to simple pistils, namely, 

 the Follicle and the Legume. 



355. The Follicle is a fruit of a simple 

 pistil opening along the inner suture 

 (307). The pods of the Paeony, Col- 

 umbine, Larkspur, Marsh-Marigold 

 (Fig. 302), and Milkweed are of this 

 kind. The seam along which 



the follicle opens answers to 

 the edges of the pistil-leaf 

 (Fig. 251, 253). 



356. The Legume or true 



Pod, like the Pea-pod (Fig. 302 

 303), is similar to the follicle, only it opens by the outer as well as 

 the inner or ventral suture (307), that is, by what answers to the 

 midrib as well as by what answers to the united margins of the leaf. 

 It splits therefore into two pieces, which are called valves. The le- 

 gume belongs to plants of the Pulse family, which are accordingly 

 termed Leguminosa, that is, leguminous plants. So the fruits of this 

 family keep the name of legume, whatever their form, and whether 

 they open or not. A legume divided across into one-seeded joints, 

 which separate when ripe, as in Tick-Trefoil (Fig. 304), is named a 

 Lament. 



357. The true Capsule is the pod of a compound pistil. Like the 

 ovary it resulted from, it may be one-celled, or it may have as many 

 cells as there are carpels in its composition. It may discharge its 

 seeds through chinks or pores, as in the Poppy, or burst irregularly 

 in some part, as in Lobelia and the Snapdragon ; but commonly it 

 splits open (or is dehiscent) lengthwise into regular pieces, called 

 valves. 



FIG. 300. Samara or key of the White Ash. 301. Samara of the American Elm 



FIG. 30a Follicle of Marsh-Marigold (Caltha palustris). 



'FIG. 303. Legume of a Sweet Pea, opened. 



FIG 304. Loment or jointed legume of Tick-Trefoil (Desino(7iuin,J. 



