The _Gymnosperms_ include a group of small palm-like trees and shrubs (the _Cycadeæ_), of which the so-called Sago Palm is a representative; and the _Coniferæ_ or cone-bearing shrubs and trees, which may be spoken of collectively as the Pines. In the latter the leaves are either stiff, linear, and needle-like, or short and scale-like, or are divided into narrow lobes; and the plants are noted for their resinous secretions. The flowers are always unisexual, and are generally arranged in cylindrical or short catkins, where they are protected by closely packed scales; but the female flowers may be solitary. There is no calyx or corolla, but the naked ovules and seeds are sometimes more or less enclosed in the scales (_bracts_) or in a fleshy disc. The _Angiosperms_ form the highest division of the flowering plants; and are subdivided into two extensive groups--the _Monocotyledons_ and the _Dicotyledons_. The chief distinguishing feature of these is that implied in the above names, the embryo of the former containing but one rudimentary leaf (_cotyledon_), while that of the latter contains two. The Monocotyledons are also characterised by having the bundles of vessels (_vascular bundles_) of the stems dispersed; the veins of the leaves are also usually parallel, and the parts of the flower are arranged in whorls of three or six. In the Dicotyledons the vascular bundles of the stem are united into a ring which surrounds a central pith; the veins of the leaves form a network, and the parts of the flower are arranged in whorls of four or five. We are now enabled to understand the relative positions of the principal groups of plants in the scale of vegetable life, and to locate approximately the forms with which we have to deal; and to aid the reader in this portion of his work we present a brief summary of the classification of plants in the form of a table for reference:-- THE CLASSIFICATION OF PLANTS I. =CRYPTOGAMIA=--Flowerless plants. (_a_) =THALLOPHYTES=--Leafless, cellular plants. 1. =Protophyta=--Unicellular plants. 2. =Algæ=--Sea weeds, &c. 3. =Fungi=--Mushrooms, &c. (_b_) =CHARALES.= (_c_) =MUSCINEÆ.= 1. =Hepaticæ=--Liverworts. 2. =Musci=--Mosses. (_d_) =VASCULAR CRYPTOGAMS.= 1. =Filicales=--Ferns. 2. =Equisetales=--Horsetails. 3. =Lycopodiales=--Club-mosses. 4. =Rhizocarpeæ=--Water ferns. 5. =Selaginellales.= II. =PHANEROGAMIA.= (_a_) =GYMNOSPERMIA.= 1. =Cycadeæ=--Cycads. 2. =Coniferæ=--Cone-bearing trees. (_b_) =ANGIOSPERMS.= 1. =Monocotyledons.= 2. =Dicotyledons.=