THE LEAF 255 
Dicotyi LEAVEs 
. Epidermal! cells usually iso-diametric 
or sinuous in surface sections. 
. The stomata are on the whole more 
numerous but smaller. 
. Non-glandular and glandular hairs 
frequent on upper but more fre- 
quent on lower surface, or both. 
. Leaf glands which excrete varied 
products are rather abundant. 
. Water stomata over the upper sur- 
face, more rarely over the lower 
surface, are frequent, especially 
along margins of leaves. 
. Palisade and spongy parenchyma 
in dicotyledons are more distinct 
and palisade parenchyma is 
denser. 
. The vascular bundles, in their in- 
trinsic elements, are more indur- 
ated but the accessory fibrous 
sheath is feebly developed. 
. A greater variety of accessory prod- 
ucts of assimilation are devel- 
oped. 
Monocotyt LEAVES 
1. Epidermal cells usually elongate 
with rectilinear vertical walls, in 
surface sections. 
. Stomata larger. 
. Hairs rare in Monocotyls. 
. Leaf glands rare and only seen as a 
rule on the sepals. 
. Water stomata absent or very rare. 
Present in some Araceae. 
. Palisade and spongy parenchyma 
are less distinct and dense. 
. The vascular bundles, in their in- 
trinsic elements, are less indu- 
rated. The fibrous sheath is 
strongly developed. 
. A comparatively small variety of 
accessory products of assimilation 
are developed. 
