108 BOTANY. 
to proceed. When the seed is placed in the ground, in favourable condi- 
tions of heat and moisture, it soon begins to ger- 
minate! or sprout. Changes take place within 
the seed itself, new cells are formed, and through 
a hole in the covering of the seed, not in general 
easily perceptible before, a little root is sent out, 
which descends into the soil to seek nourishment ; 
whilst from the same part of the seed a shoot 
ascends into the air, and begins to develop leaves, by 
which also the plant seeks nourishment ; for it is 
sustained not only from the soil through its roots, 
but from the air through its leaves, the leaves 
being organs of nutrition as much as the roots, 
and equally essential to life. The part of the seed 
which extends downward into the soil and forms 
the root, is called the radvcle? or little root (¢, fig. 
72); the ascending part, which becomes the stem, 
and from which leaves, flowers, and fruit are devel- 
oped, is called the plumule? or little feather (0, fig. 72), many plants, when 
they first spring from the ground, having somewhat the appearance which 
this term suggests. | 
Growth and Structure of Plants—As plants grow, the stem of many 
divides and subdivides into branches, but there are others in which no 
such division takes place, and there are many, as primroses, lilies, and 
hyacinths, which send up no stem, but have only flower-stalks, such as 
spring from the buds of other plants, arising from the crown of the root. 
There are also plants which have neither stem nor leaves, nor even roots, 
but which imbibe their nourishment through their whole surface from 
the air or water in which they live, as lichens, fungi, and sea-weeds. 
In the very lowest and simplest forms of vegetation, nothing is to be 
found but a mere cell, or a number of cells variously grouped together, 
each cell, however, appearing to be an independent plant. 
Cellular Tissue and Vascular Tissue.—Some portions of all plants, and 
the whole of some, consist of what is called cellular tisswe—that is, of mere . 
cells variously aggregated. Cellular tissue abounds in the soft and fleshy 
parts of plants; and some of these are often greatly developed and 
increased by cultivation, so as to render the plant more useful to man. 
The parts of plants used for food consist mainly of cellular tissue. 
Cells, however, often extend in particular directions as the plant grows, 
or numerous cells are combined into one, some part of the separating 

Fig. 72.—A bean beginning 
to grow, spread open. 
1 Latin germinare, to sprout. 3 From Latin plwma, a feather. 
2 From Latin radix, radicis, a root. 
