CHAP. II. 
ELEMENTARY ORGANS. 
297 
bedded. It is, therefore, readily permeable to fluid, although 
it has no visible pores. 
In all cases of wounds, or even of the developement of new 
parts, cellular tissue is first generated : for example, the gra- 
nulations that form at the extremity of a cutting when em- 
bedded in earth, or on the lips of incisions in the wood or 
bark ; the extremities of young roots ; scales, which are 
generally the commencement of leaves; pith, which is the 
first part created, when the stem shoots up ; nascent stamens 
and pistils ; ovules ; and, finally, many rudimentary parts : in 
all these at first, or constantly, is formed cellular tissue alone. 
It is that from which leaf-huds are generated. These organs 
always appear from some part of the medullary system ; 
when adventitious, from the ends of the medullary rays if 
developed by stems, or from the parenchyma if appearing 
upon leaves. 
It may be considered the flesh of vegetable bodies. The 
matter which surrounds and keeps in their place all the 
ramifications or divisions of the vascular system is cellular 
tissue. In it the plates of wood of exogenous plants, the 
woody bundles of endogenous plants, the veins of leaves, and, 
indeed, the whole of the central system of all of them, are 
either embedded or enclosed. 
The action of fertilisation appears to take place exclusively 
through its agency. Pollen is only cellular tissue in a parti- 
cular state ; the coats of the anther are composed entirely of 
it ; and the tissue of the stigma, through which fertilisation 
is conveyed to the ovules, is merely a modification of the 
cellular. The ovules themselves, with their sacs, at the time 
they receive the vivifying influence, are a semitransparent 
congeries of cellules. 
It is, finally, the tissue in which chiefiy amylaceous or sac-- 
charine secretions are deposited. These occur chiefly in tubers, 
as in the Potato and Arrow-root ; in rhizomata, as in the 
Ginger ; in soft stems, such as those of the Sago- Palm and 
Sugar-cane ; in albumen, as that of Corn ; in pith, as in the 
Cassava ; in the disk of the flower, as in Amygdalus ; and, 
finally, in the bark, as in all exogenous plants ; and cellular 
tissue is the principal, or exclusive, constituent of these. 
