whether the seed is mono: or dicotyledonous. Having by this summary process decided to which
division of the system a plant belongs we proceed with our investigation. Let us suppose the
plant is dicotyledonous and that we still follow DeCandolle as our guide.
He divides Dicotyledonous or Exogenous plants into 4 sub-classes the characters of which
are taken from the fructification. These four are respectively named Thalamiflorce, Caliciflorae
Corolliflorae and Monochlamydeae.
I. Thalamiflorae are distinguished by having several distinct petals and stamens inserted on
the Thalamus or receptacle of the flower, and not cohering with the calyx.—(flowers hypogynous.)
The petals and stamens do however occasionally cohere as for example in Malvaceae so as
in some degree to resemble those of the third class Corolliflorae, from which however in all such
cases their numerous nearly distinct, carpels distinguish them.
II. Calyciflorae have also several petals, either distinct or united to each other, but inserted
along with the stamens on the calyx, usually through the medium of a disk lining its tube or
concave portion.—(flowers pyrigynous or epigynous).
III. Corolliflorae have the petals united into one bearing the stamens and inserted on the
thalamus, or receptacle (hypogynous).
IV. Monochlamydeae have either no corolla or the petals if present are united to the
calyx forming together a single, not double, perigonium or verticel of flower leaves round the
pistil.
Before going further it may be proper to observe, that this is a mere artificial classification
intended simply to facilitate the arrangement of the orders in a linear series, and to aid in enabling
us to determine to what part of that series we ought to turn to find the order of any plant
under investigation. While it pretty well fulfills these objects, it must be acknowledged, that,
like all such artificial combinations it is liable on the one hand to produce unnatural associations,
and on the other to separate orders most nearly allied, besides presenting examples of Mono-
chlamydeous and dichlamedyous genera in the same order. These, objections, however, apply
to the arrangement, only, of the orders, not to the orders themselves, which may, though individually
perfectly natural, be most unnaturally placed in relation to each other, a defect, to
which all systems yet proposed is more or less liable, and we may almost assume, ever will be,
when we take into consideration that families of plants like provinces of a kingdom, touch each
other, not by one point only but on all sides and that we might as well expect to arrange the latter
in a correct, linear series as the equally irregularly formed and closely surrounded provinces,
that is the natural orders, of the vegetable kingdom. All therefore that can be looked for is well
constructed and correctly defined orders or provinces, the boundaries of which should be as
clearly marked out as the nature of the subjects will permit. The after arrangement of these, in
such a manner as to facilitate reference, or to follow out the simile of kingdoms and provinces,
to teach under what latitude and longitude we must look first for the province (the natural order)
and then for the town (the genus) to which the subject of our enquiry (the species) belongs.
Various plans have been tried for the attainment of this desideratum, but no one seems yet to
have obtained such general favour as the one the ground work of which I have sketched, even
though liable to such striking defects as those I have indicated. But to proceed.
I. T halamiflorae.—This sub-class includes all the plants originably referred by Jussieu to
his 13th class (Polypetalae hypogena) those namely with hypogynous or inferior flowers, and
several petals or which has more recently received the name of Hypopetalee: that is petals
inferior to the pistil or ovary. This is a large class, presenting many anomalies, but upon the
whole, generally of sufficiently easy application in practice.
II. C alyciflor.®.—This sub-class is more «difficult, and often not easily distinguished
from either the preceding or the succeeding one. It is divided into six sections.
1. Peripetalce with several distinct petals inserted on the calyx towards its base,leaving the
ovary superior or free—Leguminosce, the section Potentillece of Rosacece, and Salicariece all afford
easily understood examples of this section.
2. Epipetalce.—ln this section the tube of the calyx is prolonged and lined by the torus
which forms a small disk on the summit of the ovary, and the ovary is4enclos^d by and coheres with
calyx tube : the distinct petals and stamens are inserted on the outside of the disk. The ovary is
here said to be inferior or adherent and the flower superior. Rosece, Pomeae and Combretacece,
apparently afford examples of this section, but want the disk on the summit of the ovary.
Umbelliferee, Araliacece and Cornece are the only orders referred here as being truly epipetalous.
3. Epicorallce Corisantherce ; this section differs from the last in having the petals united,
forming a monopetalous corolla, bearing the stamens inserted on its tube, and the anthers not
cohering round the style. The common honey-suckle is a familiar example of this section to
which also the elder, the coffee, valerian &c., that is the orders Caprifoliacece, Rubiacece, Valeri-
anece &c. belong.
4. Epicorollce Synantherce: the essential distinction between this and the preceding
section consists in the anthers of this cohering by their edges, forming a tube round the style,
and from the succeeding by the corolla being inserted on the top of the ovary not on the bottom
or tube of the calyx.
5. To this section the vast order Compositce alone belongs ; as examples of which it may
suffice to mention the humble Daisy, the common Thistle, the Artichoke, the Dandilion, and
gaudy Dalia to enable every one to understand what is meant by a compound flower the general
flower of each of these being made up of a congeries of small ones.
6. Pericorollae: in this, as in the two preceding sections, the petals are united into a monopetalous
Corolla, but in place of being, inserted on the top of the ovary, it is inserted on the tube,
or towards the base of the calyx; leaving the ovary either partially or all together free.
The Lobelia, the Hairbell, and Heath tribes afford examples of this last section of the 2d
class.
III. C orrolliflor®.—This sub-class differs from the three last sections of the preceding
in the insertion of the corolla only, like them the corolla is monopetalous bearing the stamens,
but in place of being inserted on the calyx, (perigynous) springs from the receptacle or base of
the flower, inferior to the ovary, (hypogynous) hence in the language of Jussieu the section is
now named Hypocorollae (see table below).
The Jasmines and Convolvulus afford the most familiar examples of this class but the
Gentians, Trumpet flowers (Bignonia) Heliotropes,Verbenas, Solanums (Brinjal, Potatoe,&c.) all
belong to it.
IV. M onochlamyde®.— This sub-class is characterized by having a single perianth, that
is, only one verticel or whorl of floral envelopes, or if two are any time present, the petals adhere
to the calyx. It is divided into four sections.
1. Hypostamineae here the stamens are inserted on the receptacle and the ovary is free
even though concealed within the tube of the calyx to which it does not adhere. The Marvel
of Peru ( Mirabilis JalapaJ, so much prized as a garden ornament, and the Amaranthus appertain
to this section. The flower of the former often so delicately variegated is in truth only
a petaloid expansion of the calyx, and not a corolla, in the glabose inflated bottom of which, the
filaments and ovary are found perfectly free This lower portion of the calyx afterwards forms
the black^shell-like covering of the seed.
2. Peristamzneae. In this the stamens are inserted on the calyx, not hypogynous.
Che nopodium, Polygonum and the beautiful Begonia are examples of this section.