arma oe. N ™ Oe Me 7 ie ee 2 tp My ‘fae L \ Ls - >. ase 
th Pi hee eee ok | J Ap 4 ty } Se Ae Nia eS ME ee Pip * f C1 ae a me 
é : 5 
The External Form of Plants. 71 
downwards, and the stem-bud upwards. The stem-bud, or 
plumule, is divided from the outset into stem and leaves. | 
The leaves therefore do not grow on a stem already 
_ formed ; on the contrary, they constitute from the first, to- 
gether with the stem, a hemispherical body consisting of 
O 
t 
ys 
ue 
—2 
fk” 
a z ee: Ges PRE 
darts SSA Se #S 
=. ee Bh soy = 
OOP IITA! ; 
Lit 
— 
SUT] Pou 
ee ee 
Fic. 99.—Germinating bean; a & Fic. 1oo.—Longitudinal section through the 
- cotyledons; cd leaves; e ter- apex of a root of Asfidistra elatior; wh 
minal bud; % primary root; ¢ root-cap ; M pith; o epidermis; G’ narrow 
lateral roots, -. ae vessels ; G’* broad reticulate vessels. 
x 75). 
primary parenchyma, which then becomes lobed. It is ~ 
therefore impossible to draw accurate lines of demarcation 
between the three main organs of the plant, the roof, stem, 
and /eaf. ‘The stem is distinguished from the root only by 
=~ 
