32 ELEMENTARY. BOTANY 
much more cut up than ordinary foliage leaves. An example 
of this occurs in water crowfoot, where the leaves above the 
water are round and at least an inch in diameter, whilst the 
leaves in the water are narrow and filamentous. 
Modinen oe Clade | of a leaf may be modified into 
tions of tendrils; this is very common in the pea family ; 
Lamina. thus, in sweet pea, the last two pairs of leaflets 
and the terminal one have become tendrils, by means of which 
the plant climbs (Fig. 32). In some few instances the leaves 
may become spines ; this is well seen in barberry, where the 
lower leaves are foliaceous, the upper ones spiny (Plate I., 
Fig. 30). 
~ In plants which feed on insects the blade is usually fur- 
nished with arrangements for entrapping the insect and for 
‘manufacturing a juice by which it can digest the insect. In 
sundew the leaves have hairs. As an insect alights on the 
leaf, it curls up, the hairs serving to hold the insect; each 
hair has at its tip a little gland, which makes the juice that is 
poured out on the insect. 
Functions be functions of foliage leaves will be dis- 
of Foliage cussed in connection with the phy siology of the 
Leaves. plan . 
DESCRIPTION OF FOLIAGE LEAF. 
Position.— Radical or cauline. 
Arrangement on Stem.—Alternate, opposite, whorled. 
Petiole.—If present, the leaf is petiolate. 
If absent, the leaf is sessile. 
Length of petiole as compared with length of lamina. 
Sheath.—Stipulate or ex-stipulate. 
Size of stipules. 
Lamina— 
(a) Simple (divided or undivided). | opscnd 
(b) Venation.—Pinnate or palmate. 
(c) Shape.—This may be indicated by an accurate drawing. 
_ (a) Margin.—Entire or indented; if indented—serrate, geninte, 
or crenate. 
(e) Apex.—Pointed or blunt; rounded or hollowed out. 
(f) Surface.— Hairy or smooth, 
(g) Modifications of Lamina. —Tendrils, spines, etc. 
