Page:British Flowering Plants.djvu/24

10 When, in a pinnate leaf, the leaflets are arranged on the sides of the leaf-stalk with a terminal leaflet, the leaf is called imparipinnate (fig. 57); when the terminal leaflet is wanting, paripinnate (fig. 58); intteruptedly pinnate when the pairs of leaflets are alternately larger and smaller (fig. 59); and bi-pinnate when the leaflets are themselves compound (fig. 60). Other forms of compound leaves are palmate-partite (fig. 61), lyrate (fig. 62), and pedate (fig- 63).

Many leaves are divided into three principal parts: the lamina, or surface of the leaf; the foot-stalk; and the clasping base, embracing a portion of the stem of the plant (fig. 64). When the leaf-stalk is absent, the leaf is said to be sessile (fig. 65). When the sessile leaf interruptedly pinnate when the pairs of leaflets are encloses the stem, it is called amplexicaul (fig. 66); and when the stem grows through it, it is said to be perfoliate (fig. 67). Sometimes small leaves are formed near the base of the leaf-stalk. These are called stipules, and the leaf is then said to be stipulate (figs. 68-71).

Occasionally, as in the Plantains, there is a "rosette" of leaves close to the ground (fig. 72);