THE PRINCIPLES OF BOTANY. 579 
divisible into classes depending upon facts in the situation or 
structure of the floral organs. 
In 1830 Lindley proposed two classes —Vasculares or 
flowering plants, and Cellulares or non-flowering plants; 
these were divided into sub-classes or tribes, depending upon 
various circumstances. 
In 1843 Adolphe Brongniart propounded a system of clas¬ 
sification, in which ‘‘albumen is regarded of high value, 
especially the difference between farinaceous albumen and 
that which is fleshy, oily, and horny, which last are taken to 
be slight modifications of each other.” 
This slight account of the bases of different systems may 
serve to show the interest that has been taken in the subject 
of classification; all afford something good, and probably, as 
our knowledge advances, it will be found that each author 
has contributed something to that precision all should aim 
after. 
The classification which we shall adopt will be that of 
Professor Lindley for 1845, as being not only in itself the 
easiest of adoption, but because his ‘Vegetable Kingdom’ 
will be so handy for constant reference. His plan of alli¬ 
ances, too, will be found convenient in any description in 
which mere principles have to be evolved. 
Classes. 
Asexual or Flotcerless Flants. 
Stems and leaves undistinguishable . . .1. Thallogens. 
Stems and leaves distinguishable . . .11. Acrogens. 
Sexual or Flotcering Plants. 
Fructification springing from a thallus . . III. Khizogens. 
Fructification springing from a stem : 
Wood of stem joungest in the centre; cotyledon 
single. Leaves ))arallel veined, permanent; 
wood of stem always confused . . . IV. Endogens. 
Leaves net-veined, deciduous; wood of the stem, 
when perennial, arranged in a circle with a cen¬ 
tral pith . . . . .V. Lictyogens. 
Wood of stem youngest at the circumference, always 
concentrie; cotyledons two or more: 
Seeds quite naked .... VI. Gymnogens. 
Seeds enclosed in seed vessels . . . VII. Exogens, 
Here we have seven classes, which, after all, may prac¬ 
tically be reduced to four, two of which belong to the flower¬ 
less and two to the flowering plants ; and if we shortly review 
these, we shall find that nothing is more natural than that 
the simply cellular plants, without stems or leaves, should be 
