3 Satalig very small leaves whieh” can be raade” out Sole bee a 
the young state; but in some cases, as the potato, there ie 
are a number of ae concealed in depressions, which arey; pes 
me called eyes ( Figs. 116, 117). Many plants form only one 
_.. tuber, as the pig-nut, Carum bulbocastanum (Fig. 118), 
“*. others several, as the potato. The spherical or palmate 
Fic. 117.—A tuber c formed 
in the axil between a small 
leaf 4 and the stem a. (x 2.) 
fi 
‘Fic. 116.—A six-weeks’ old potato-plant developed 
74 from*the seed, the upper branches a 6 being cut 
ort 3a cotyledons ; in the axils of the cotyledons 
fry" are ‘developed the underground branches e e, which 
be penetrate into the ground and form tubers fg at 
their apex or in the axils of small leaves. The 
hy ‘tubers are formed only on the branches which are Fic. 118.—Single tuber of the 
ee produced in the axils of the cotyledons, never on pig-nut, Carum bulbocasta- | 
PCE ED, the true roots %. num (natural size). ' 
‘tubers of some orchids (Figs. 119, 120) are considered by a 
‘some to be tuberous roots, by others true tubers. ae . 
~The dz is also fleshy, but is distinguished by its leaves, 
gaa r 
if a} 
/ vy 
which [in the form of scales] surround the solid base of = ~ 
the stem which is called the disc, or are attached to its . 
a apex. ‘This plate or disc is either comparatively large, and 
| _ when surrounded by only a few leaves, as in the crocus, is: 
