THE SEED 315 
seeds show a larger nourishing tissue region and a smaller embryo 
region, Examples: Nux Vomica, Myristica, Coxcuicum, 
Castor, etc. 
Gross STRUCTURE OF A Monocotyt SEED (wiTH Frurr WALL 
ATTACHED), INDIAN Corn.—The ripened seed of Indian Corn is 
surrounded by a thin, tough pericarp which is firmly adherent to 
and inseparable from the spermoderm or seed coat. Because of 
this fact, while in reality a fruit called a caryopsis or grain, this 
structure is sometimes erroneously termed a seed. 
The mature grain of most varieties of Indian Corn is flattened 
and somewhat triangular in outline, the summit being broad and 
the base comparatively narrow. The summit is indented and 
often marked by a small point which represents a vestige of the 
style. The base or “tip” region marks the part of the grain 
which was inserted into the cob. Upon it may be found papery 
chaff, representing parts of the pistillate spikelet. The groove 
noted on the broader surface indicates the position of the 
embryo. 
HisToLoGy OF THE INDIAN Corn SEED (wiTH FRuir WALL 
ATTACHED).—If a longitudinal section be cut through the lesser 
diameter of a soaked grain, the following histologic character- 
istics will be observed: 
1. The Pericarp or ripened ovarian wall which, alike with all 
other grains, adheres firmly to the wall of the seed forming a 
portion of the skin of the grain. ‘The pericarp comprises an 
outer epicarp of elongated cells with thin cuticle, a mesocarp of 
thicker walled cells without, becoming thinner within, and a 
layer of tube cells. 
2. The SPpERMODERM or seed coat, a single layer of delicate 
elongated cells. . 
3. The PerRispeERM, another layer directly underneath the 
Spermoderm, difficult to distinguish without special treatment, 
and representing the ripened nucellar tissue of the ovule. 
4. The ENposPERM or nourishing tissue, consisting of: (a) The 
Aleurone Layer, for the most part a single row of cells, containing 
aleurone grains. Some of the cells may be seen to be divided by 
tangential partitions. (6) Starch Parenchyma, consisting of two 
regions: an outer horny zone composed of cells containing for the 
