6 ELEMENTARY BOTANY 
(Latin scutwm, a shield) ; this answers in part to the cotyledon. 
The rest of the grain, chiefly yellow, is food material. 
Fics. 4 To 7.—Mams. 
4,—HXxTERNAL VIEW OFGRAIN. 5.—EMBRYO, 
6 AND 7,—SEEDLINGS, 
x, remains of style; y, stalk of attachment 
to cob; sc, scutellum ; p, plumule; 7, radicle ; 
sh, root-sheath ; rh, root-hairs ; e, food-material. 
REMOVED FROM GRAIN. 
lateral roots. 







Stages in The first 
| Germination. step in 
germination is in- 
variably the swelling 
of the seed owing 
to the taking in of 
: water; then the skin 
+ bursts in consequence 
. of the pressure of 
the radicle against 
it; this soon pro- 
~ trudes, and the skin 
goes on _ splitting 
until the plumule 
also emerges. The 
radicle soon gives 
off branches forming 
In maize, two other roots, called secondary, 
arise from the scutellum. The first root has a little sheath at its 
base, so that it is possible to tell which the primary root is. 
The plumule grows into the shoot; in maize the leaves 
ensheathe the stem. 
COMPARISON OF SEED OF BEAN AND 
GRAIN OF MAIZE, 
BEAN. 
1. A seed. 
2. Brown skin is testa. 
3. Two fleshy cotyledons, 
containing food. 
4. Food stored within the 
; young plant. 
5. Radicle develops into 
primary root, bearing 
lateral branches. 
6. Plumule grows into shoot. 
MAIZE. 
A seed + seed-vessel. 
Skin is testa + wall of seed- 
vessel. 
One cotyledon. 
Food supply external to the 
young plant. 
Radicle develops into primary 
root with lateral branches ; 
in addition there are two 
other roots, which are 
soon as long as _ the 
primary root. 
Plumule grows into shoot. 
