36 



BOTANY 



PART I 



Cyperaceae it is completely grown together. The sheath of the 

 Grasses is prolonged at the base of the lamina into a scaly out- 

 growth, the ligule (/). Such a sheath, while protecting the lower 

 part of the internodes, which remain soft and in a state of growth, 

 gives them at the same time rigidity. STIPULES are lateral 

 appendages sometimes found at the base of leaves. When present 

 they may be either small and inconspicuous (Fig. 37 nb), or may 

 attain a considerable size. When their function is merely to 

 protect the young growth in the bud, they are usually of a brown 

 or yellow colour, and are not persistent ; whereas, if destined to 

 become assimilatory organs, and to assist in providing nourishment, 



FIG. 37. ttin\Cherry(l'runusAviuin). FIG. 3S.Helleboru.- fott'idu*. Foliage leaf 



Bud-scales (1-3) and the transition (Oiaiul intermediate forms U-tweeii this 



forms (4-6) to the foliage leaf (7),; and the bract (h). (Reduced.) 



sp, leaf -blade; s, leaf-stalk; nb, 

 stipules. (Reduced slightly.) 



they are green, and may assume the structure and form of the 

 leaf-blade, which sometimes becomes modified and adapted to other 

 purposes (Figs. 48, 49). Normally, the stipules are two in number, 

 that is, one on each side of the petiole. In many species of Galium, 

 where*the stipules resemble leaf-blades, the leaf-whorls appear to be 

 composed of six members, but consist actually of but two leaves 

 with their four stipules, which may be easily distinguished by the 

 absence of any buds in their axils. In other species of the same 

 genus (Galium cruciatum and palujtre) there are only four members in 

 the whorls, as each two adjoining stipules become united. In many 

 cases, as in the Rose and the Clover, the stipules have the form of 

 appendages to the enlarged leaf-base. Sometimes both stipules are 

 united into a single one, which then appears to have an axillary 



