2 l6 
PHARMACEUTICAL BOTANY 
4. The Endosperm 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. ( b ) Starch Parenchyma, consisting of two 
regions: an outer horny zone composed of cells containing for the 
most part polygonal starch grains and oil droplets; and an inner 
mealy zone of cells with mostly rounded starch grains. 
5. The Embryo , consisting of a single shield-shaped cotyledon 
adjoining the endosperm, the plumule or rudimentary bud at the 
end of the caulicle or rudimentary stem and the radicle or rudimen¬ 
tary root, with its tip covered by a root cap. Continuous with the 
root cap is a root sheath or coleorhiza. The cotyledon or seed leaf 
consists of two parts: the scutellum which lies next to the endosperm, 
and is an organ of absorption; and the sheating portion which sur¬ 
rounds and protects the rest of the embryo. 
The embryo contains oil and proteids, but no starch. 
If a similar longitudinal section of a soaked grain be mounted in 
dilute iodine solution, the contents of the aleurone cells will be col¬ 
ored yellow indicating their proteid nature, while the starch grains 
will take on a blue to violet coloration. The endosperm will be 
observed taking up most of the room within the seed coat. The con¬ 
tents of its cells are not baled out to the embryo until after germina¬ 
tion begins. Indian Corn is therefore an albuminous seed. 
A MONOCOTYL SEEDLING 
Germination. —When any viable seed is planted in suitable soil, 
and furnished with oxygen and water and a certain degree of heat, 
germination takes place. In the presence of moisture, etc., the seed 
swells, the ferments present within the cells of the endosper n then 
change the insoluble proteid, starch, and oil to soluble materials, 
which, in the ckse of Indian Corn, are absorbed in solution by the 
scutellum which bales this nourishment out to other parts of the 
growing embryo, there to be used in part in constructing new tissues, 
and in part to be consumed by oxidation or respiration. The process 
of respiration or breathing takes place when the plant takes in oxy¬ 
gen and gives off carbon dioxide. The oxygen oxidizes the tissues 
