13 6 
PHARMACEUTICAL BOTANY 
cells. This mode of development is seen in theLabiat(e,Papilionace(E, 
Crucifertz , Solanacea, Crassulacece, Cactacecz, and Begoniacece, also 
in a number of ferns. 
Histologic Differences between Leaves of Dicotyledsuo and 
Monocotyledons. — The following may be cited as broad compara- 
tive histologic differences between Dicotyl and Monocotyl leaves: 
Dicotyl Leaves 
1. Epidermal cells usually iso-dia- 
metric or sinuous. 
2. The stomata are on the whole more 
numerous but smaller. 
3. Non-glandular and glandular hairs 
frequent on upper but more fre- 
quent on lower surface, or both. 
4. Leaf glands which excrete varied 
products are rather abundant. 
5. Water stomata over the upper sur- 
face, more rarely over the lower 
surface, are frequent, especially 
along margins of leaves. 
6. Palisade and spongy parenchyma 
in dicotyledons are more distinct 
and palisade parenchyma is 
denser. 
7. The vascular bundles, in their in- 
trinsic elements, are more indur- 
ated but the accessory fibrous 
sheath is feebly developed. 
8. A greater variety of accessory prod- 
ucts of assimilation are de- 
veloped. 
Monocotyl Leaves 
1. Epidermal cells usually elongate 
and equilateral. 
2. Stomata larger. 
3. Hairs rare in Monocotyls. 
4. Leaf glands rare and only seen as a 
rule on the sepals. 
5. Water stomata absent or very rare. 
Present in some Aracetz. 
6. Palisade and spongy parenchyma 
is less distinct and dense. 
7. The vascular bundles, in their in- 
trinsic elements, are less indur- 
ated. The fibrous sheath is 
strongly developed. 
8. A comparatively small variety of 
accessory products of assimila- 
tion are developed. 
INFLORESCENCE 
Inflorescence or Anthotaxy. — A typical flower consists of four 
whorls of leaves modified for the purpose of reproduction, and com- 
pactly placed on a stem. The terms Inflorescence and Anthotaxy are 
applied to the arrangement of the flowers and their position on the 
stem, both of which are governed by the same law which determines 
the arrangement of leaves. For this reason flower buds are always 
either terminal or axillary. In either case the bud may develop a 
