122 
YEGETABLE PHYSIOLOGY. 
ture suspended in the atmosphere, to be liberally syringed daily with tepid soft water. When, 
however, the plants are first imported, they must be thoroughly washed, both root, branch, 
and foliage, for until they are cleared of all kinds of filth it will be found impossible to grow 
them to anything like perfection. Rustic baskets, or pots with perforated sides, are the most 
suitable to grow them in, and the compost used should be very fibrous peat and sphagnum moss, 
liberally intermixed with charcoal in large and small pieces ; press the compost close together, 
and to make sure that the plants are firm in the pots, use a few pegs to hold the soil together. 
Suspend the pot or basket close to the glass and take care to keep a moist atmosphere at all 
times, and the plants when once established will then grow with great freedom. Water 
liberally, and shade in very sunny weather, and take care that the plants are not broiled by a 
too free admission of air in immediate contact with them. When the growth is completed, and 
more especially after they begin to show bloom, they may be kept comparatively dry, but 
they must not at any time be subjected to a low temperature.—A. 
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By ABTHUB HENFBEY, Esq., F.L.S., Lecturer on Botany at St. George’s Hospital. 
THE ELEMENTARY STB.HCTUE.E OF PLANTS. 
)?N our last chapter, we examined the microscopic components of which plants, generally, are built 
lv up, and the reader will now be prepared for a more particular account of the manner in which the 
different forms of elementary organs occur in different plants ; but, as it is not intended to enter, 
in these papers, into a minute account of the anatomy of the different parts of a vegetable, and since, 
in the descriptions of roots, stems, leaves, &c., I shall dwell upon their elementary construction so 
far as is necessary for the explanation of the causes of the facts observed, or the practical operations 
carried on in horticulture on such parts, I shall here merely preface those more special observations, 
by a brief summary of the general mode of distribution of the elementary tissues. 
It has been said already, that all vegetable structure consists, at its first production, of mem¬ 
branous cells filled with nutrient juices, and that these cells undergo various changes of form and 
consistence, according to the part of the perfect plant in which they are situated, and as plants differ 
so much in habit and conformation, according to the kind of plant which they contribute to form. 
Moreover, every plant, from the microscopic Alga, to the loftiest forest tree, is at its birth a single, 
simple, membranous cell, and while the former remains in the same condition throughout its brief 
existence, the latter gains its majestic proportions by the process of self-multiplication of cells, all 
descended by generations, continuing an unbroken line through centuries, from that one original, 
mysteriously endowed, germ-cell. 
Taking a general view of the Vegetable Kingdom, we find that the nature of the changes which 
the original cellular tissue undergoes, before the plant arrives at maturity, is a tolerably good charac¬ 
teristic on which to found comparisons as to rank in the scale of vegetation for the purposes of classi¬ 
fication ; in other words, the elementary structure of plants, as might be expected, bears a relation to 
the complexity of external form, and the variety of the functions exercised within the individual 
plant. It may not be uninteresting, therefore, to trace briefly the various links of the chain of 
organization, proceeding from the lowest up to the highest forms, premising, however, that the 
descriptions of the tribes are not those of individual members of a series, but merely sketches of 
the general characters of groups, which, each taken as a whole, may be regarded as inferior or 
superior to one another; for, in no department of organized nature is there less ground for assuming 
the existence of a single direct graduated series of species, than in the vegetable kingdom. 
The lowest tribes of plants are wholly composed of simple cellular tissue, whence they are distin¬ 
guished by some authors by the name of the Cellular plants ; they comprehend the Algae, or family of 
the Sea-weeds, with their fresh-water allies; the Fungi, or Mushroom and Mildew tribe; and the 
Lichens. These plants, although differing among themselves to a great extent in consistence and 
texture, are all distinguished from the higher tribes by the absence of anything like spiral structures 
in their elementary organs, and, indeed, of anything like true woody, or fibrous tissues. 
The simplest Alga is a single membranous cell, those a little more advanced are mere strings of 
cells joined end to end, and where they attain great size, and a firm and resisting substance, we find 
tins to be composed solely of cells, the increased size being given by great multiplication of number, 
