10 
THE FLORIST’S JOURNAL. 
to do, will be to give you a brief outline of what is generally 
acknowledged on the subject before us, and to express my own 
opinion on those points which seem to be debatable. 
The materials of which plants are composed, or, in other 
words, the elementary organs of plants, consist of substances 
called tissue , the chemical bases of which have been found to be 
oxygen, hydrogen, and carbon, to which nitrogen is occasionally 
added, and these are found to be combined in variable propor¬ 
tions : vegetable tissue exists in three forms, which are termed 
cellular tissue , vascular tissue , and woody tissue. 
Cellular Tissue is the only kind which exists in all plants. 
It consists of little vesicles, or cells, of colourless transparent 
matter, contained within a delicate membrane, which, by cohesion, 
forms the sides of the cells; these assume a variety of forms in 
consequence of being susceptible of pressure in any direction. 
Membranous cellular tissue , in its normal form, has these vesicles 
spheroidal; but, in consequence of the pressure of the adjoining 
vesicles, they are frequently met with in other shapes : thus 
we have the oblong, and the lobed, as in many leaves; the 
square, as in the cuticle of some plants, and frequently in 
the pith ; the prismatical, as in the liber, and in the vicinity of 
vessels ; the cylindrical, as in the genus Chara, where it has 
been discovered so large, that a single bladder has been found 
to measure four inches in length, and one third of a line in di¬ 
ameter ; the fusiform, as frequently found in wood ; the muriform, 
in which the prismatical bladders, viewed laterally, are so 
arranged as to resemble the bricks in a wall $ the compressed, 
as in the cuticle of all plants, which, although composed of cells, 
assumes, in consequence of compression, the form of a simple 
membrane ; the sinuous, as in the cuticle, and frequently beneath 
it. When the edges of these vesicles fit together by plane 
surfaces, it is called parenchyma ; when they are elongated, and- 
overlap each other at the extremities, it is called prosenchyma. 
Fibrous cellular tissue , is that in which the sides of the vesicles 
are either composed of vegetable fibre and membrane in con¬ 
junction, or of fibre only. This kind occurs in the leaves of 
Sphagnum , the pith of Rubus odoratus, the parenchyma of On- 
cidium altissimum, the coating of many seeds, and the aerial 
roots of orchidaceous plants; it also constitutes the lining of 
the valves of almost all anthers. It differs from that previously 
noticed, in being composed either wholly or in part of vegetable 
