“GERMINATION 0 2 8 
plumule depends, amongst other things, on the time of year. 
In a bean grown in damp air in November, the radicle did 
not burst through the testa 
until the third day from the © 
time it was first soaked; in 
spring, the process would be 
much more rapid. oS 
Growin of Lhe raditle, 
Emoryo. having burst the 
testa, grows downwards, 
giving off branches laterally, 
whilst the plumule is pushed 
out from between the cotyle- 
dons owing to the growth in 
length of their stalks. The 
main root which arises from 
the radicle is the primary 
root; its branches are lateral 
roots. 
Structure of ith the ger- 
Grain of mination of a 
moe ean’ ‘seed may 
be compared that of maize. 
A grain of maize is not merely 
a seed ; it is the seed and the 
seed-vessel, so that it answers 
not only to the seed of the 
bean, but to the seed and the 

Fic. 3.—BEAN SEEDLING. 
t, testa ; stk, stalk of cotyledon ; 
rt, primary root ; dat, lateral roots ; 
rh, root-hairs ; p, plumule, 
pod. Its seed-coat has become united to its seed-vessel ; the 
skin of the grain of maize, therefore, represents testa and seed- 
vessel, 
A grain of maize is rather longer than it is broad; at the 
pointed end may be observed the rough edge, by which it 
was attached to the cob; the two broad surfaces are smooth, 
but in the centre of one of them a greyish line is visible. This 
denotes the position of plumule and radicle. Round that is a _ 
shield-like, white substance, called from its shape the scutellum 
