NATURAL ORDERS. | Ixxy 
v. ARRANGEMENT OF THE NATURAL ORDERS IN THE 
PRESENT WORK. | 
The very unequal manner in which the several Natural Orders are 
represented in the British Isles, renders it impossible, in a work confined to 
British Plants, to give any fair idea of the subclasses into which these 
Orders have been grouped, or of the principles which have guided the 
authors of the linear arrangement the most generally followed. The 
following recapitulation is therefore merely intended as a sort of table of 
contents, showing the order in which the families follow each other in the 
present work; at the same time that.the attention is called to one or 
two of the most striking, the most important, or the easiest observed 
features of each one. These characters are, however, general, not always 
without exception, and sometimes specially applicable to British genera 
only. 
CLASS J.—DICOTYLEDONS,. 
In the germination of the seed the plumula arises between two (rarely 
more) lobes or cotyledons of the embryo, or from a terminal notch. 
Subclass I. THALAMIFLORH.—Petals distinct from the calyx, and 
from each other, seldom wanting. Stamens usually hypogynous, or 
nearly so. ‘ 
* Ovary apocarpous. 
I. Ranunculacee. Petals definite. Stamens indefinite. 
II, Berberideze. Perianth and stamens in twos or threes, or their mul. 
tiples. Anthers opening by recurved valves. 
IIT. Nympheacer. Aquatic plants with indefinite petals and stamens, 
the inner petals passing gradually into the outer stamens. 
*k Ovary syncarpous. Placentas parietal (except in Polygalacez). 
- IV. Papaveracez. Perianth regular, in twos or fours. Stamens in- 
definite. 
VY. Fumariacez. Perianth very irregular, in twos or fours. Stamens 6, 
in two sets. 
VI. Cruciferee. Sepals and petals 4 each. Stamens 6, of which 2 
shorter. . 
VII. Resedaceze. Petals small, unequal, some divided. Stamens few 
but indefinite. Capsule open at the top before it is ripe. 
VIIJ. Cistaceze. Sepals 3, equal, or with additional small ones. Petals 
5, regular. Stamens indefinite. 
IX. Violacezee. Stamens 5; the anthers on the inner face of very short 
broad filaments, usually united ina ring. Capsule three-valved. 
X. Polygalacee. Perianth very irregular. Stamens 8, in two parcels; 
petals united with them. Capsule 2-celled. 
XI. Frankeniacee. As in Caryophyllacee, except the parietal pla- 
centas, 
**EE Ovary syncarpous. Placentas axile. 
XII. Caryophyllaceee. Leaves opposite, entire. Flowers regular. Stas 
mens definite, Capsule one-celled, with a free central placenta. 
