8 ELEMENTARY BOTANY 
Comparing the germination of sunflower with that of bean, 
there is this difference to note: the two cotyledons do not remain 
AND 11.—SUNFLOWER. 
Figs. 10 

in the ground as they do 
in the bean, but are borne 
upwards by the growth in 
length of the stem beneath 
the cotyledons, generally 
carrying the seed-vessel 
with them. This soon 
falls off; the cotyledons 
then expose their inner 
-surfaces to the sunlight, 
turn green, and begin to 
make food for the seedling. 
The plumule emerges 
from between the cotyle- 
dons, and grows into the 
shoot. 
The portion of the stem 
beneath the cotyledons is 
: called the —hypocotyle- 
, wall of seed-vessel; 2, attach- ee 
eh of parts of flower; 7, radicle ; donary stem (Gk. hypo= 
c, cotyledons ; m, micropyle ; rh, root- — under). 
hairs. 
COMPARISON OF GERMINATION. 
BEAN. SUNFLOWER. 
1. A seed. A seed + seed-vessel, the brown 
2. The brown skin is the seed 
coat. 
| fasiele- 
plumule. 
liwo cotyledons. 
4. Cotyledons remain in the 
ground, and do not turn 
green. 
5. One main root with lateral 
branches. 
3. Embryo 
shell being wall of seed- 
vessel. 
The seed coat is the thin, white 
skin within the brown 
shell. 
radicle. 
Embryo, plumule. 
two cotyledons. 
Cotyledonscomeabove ground 
and turn green. 
One main root with lateral 
branches. 
