THE LEAVES. 



21 



Stipules are foUaceous (s. foliacece), when of the colour and texture of leaves 

 {Heartsease, fig. 60) ; — scale-UJce (s. squamiformes), when thin like scales ; — meTn- 

 hranous (s. membranacew), when thin, flexible, and almost transparent ; — scarious 

 (s. scariosce), when dry and coriaceous {Beech, Willow, Hornbeam) ; — spinous 

 (s. spinosce), when contracted and hardened into spines {Bubinia, fig. 114) ; cirrhose 

 (s. cirrhiform.es), when they lengthen into twining tendrils {Melon, fig. 61). (We 

 retain the name of stipules for the tendrUs of the Melon and other Cucurbitacece, in 

 deference to the glossology adopted by botanists; but we shall return to this 

 subject when discussing tendrils. 



Stipules axe lateral (s. later ales), when inserted left and right of the leaf {Hearts- 

 ease, fig. 60; Robinia, fig. 114); — axillary (s. axillares), when in the axil of the 

 leaf; they are then usually consolidated into one. Such axiUary stipules may 

 cover only a part of the circumference of the stem {Drosera), or may completely 

 surround it {Buckivheat, fig. 62), in which latter case it bears the name ot ochrea. 



The ligule of grasses {ligula, Meadoiv-grass, fig. 63) is simply an axillary stipule 

 (Lig.), situated at the separatioii of the blade (l) from the sheathing petiole (g) ; 

 it may be entire, emarginate, laciniate, pilose, &c. 



Of the whorled leaves of Madder (fig. 4) and other Rubiacece, the two opposite 

 ones are alone considered as true leaves, and bear each a bud in its axil ; the others 

 are regarded as stipules, sometimes multiplied, when there are more than four, or 

 confluent, when fewer than four. 



The Nerves of the leaf are said to be parallel {n. paralleli), when. they run free 

 and parallel to the edge of the leaf and to each other {Iris, figs. 33, 79) ; — branching 

 or anastomosing {n. ramosi, anastomosantes) , when they subdivide and join each other 



{Cherry, fig. 6). 



Branching nerves are pinnate {n.pinnati), and 

 the leaves penni-nerved (/. penni-nerma), when 

 lateral nerves, like the plumes of a feather, spring 

 from the midrib {Cherry, fig. 6) ; — palmate {n. pal- 

 rtiati, palmatinervia) , when several primary nerves 

 diverge from the base of the blade like the 

 fingers of a hand {Melon, fig. 64). The primary 

 nerves only are palmate ; the secondary, tertiary, 

 &c., are always pinnately arranged. 



As regards position, leaves are radical (/. radi- 

 calia), when they spring from near the neck, 

 and hence appear to rise from the root [Dandelion, 

 fig. 29 ; Plantain, Erophila, fig. 65) ; — cauline 

 (/. caulina), when they spring from the stem and 

 branches {Rose, fig,\50). Leaves are clasping or 

 amplexicaul (/. amplexicaulia), when the base of 

 their petiole or blade surrounds the stem {Butter^ 



Henbane); — decurrent (/. decurrentia), when ^"^ lea^'"'^'' 



69. Yew. Disticlious leaves. 



cup, 



their blade is continued down the stem, forming a sort of foliaceous wing ; 



Weymouth 

 Pine. 



