6 SEEDS 
That part of a kernel which remains after removing the 
coats, consists of a creamy colored embryo, seen on one 
of the broad flat surfaces, and endosperm, which par- 
tially surrounds the embryo. Separate these two parts 
and describe each. 
The embryo is composed of a single cotyledon, a 
radicle, a plumule, and a rudimentary stem, the caulicle. 
The radicle, caulicle and plumule are imbedded in the 
flat surface of the cotyledon and can be only faintly 
seen. Lay these structures bare by removing parts of 
the cotyledon with your needle. The radicle, sur- 
rounded by a thin membrane, the root sheath, points 
toward the smaller end of the kernel, the plumule toward 
the larger, and the caulicle lies between these two. Which 
of these three structures is attached to the cotyledon? 
Cut thin cross sections of the plumule, cover them with 
water on a slide, and trv to work out the structure with 
the aid of a hand lens. 
Cut an entire kernel lengthwise thru the middle 
of the embryo perpendicular to its flat surface, and draw 
it as seen from the cut surface (x2). Make three cross 
sections of a kernel, one thru the plumule. one thru the 
caulicle, and one thru the radicle, and draw each (x2). 
Making use of your experience in studying the bean, 
four-o’clock and corn, work out the structure of the 
following seeds: pea, squash, clover and castor-bean. 
The enlargement found on one end of the castor- 
bean is known as the caruncle. On the side of the 
caruncle next to the flattened side of the bean you will 
find a small dark projection, the hilum. From the hilum 
to the opposite end of the bean note a small flat ridge, 
