230 
THE PLANT WORLD. 
photograph was made from the same section as Fig. 40, but em¬ 
braces only a small portion of the upper, left-hand end of the 
scutellum. 
In Fig. 41 the parts of the embryo may be seen in detail. PI 
is the plumule, a short axis or stem on which are borne the young 
leaves. Our figure shows two of these. The other end of the 
embryo is composed of a root sheath surrounding the embryonic 
roots, of which there are several. One of these is median, and 
appears in this figure cut longitudinally. Its histological struc¬ 
ture and that of its root cap are clearly seen. The disposition 
of the lateral roots (r) is best seen in a transverse section passing 
Fig. 47. Transverse section of a grain through the tip of the plumule. 
The groove which runs along the inner side of the grain is seen as a notch, 
which is partly filled with loose tissues derived from the nucellus, testa and 
pericarp. The groove is traversed by a strand of vascular tissue. 
through the base of the median root Pr., (Fig. 45). The asym¬ 
metry of this section is apparent, and not real, and is due to the 
fact that the cut is not exactly transverse. In the possession of 
