In this first part I shall endeavour to familiarise my readers with botanical details, as all the orders I shall describe contain a great number of genera; and to begin at the beginning, I must first tell them what is here meant by an order, and what by a genus of plants. A genus then may be compared to a family of children, all the plants in it being known by one common or generic name, in addition to their particular or specific one. Thus, if Rosa alba be spoken of, _Rosa_ is the generic name which is common to all roses, but _alba_ is the specific name which is only applied to the white rose. An order includes many genera, and bears the same affinity to a nation as a genus does to a family. In many cases the resemblance which the plants in each order bear to each other is sufficiently strong to enable the student to recognise them at first sight; in the same manner as you may generally know a Frenchman or a German from an Englishman, even before you hear him speak. But unfortunately this general outward resemblance does not always exist, and it is necessary for the student to become acquainted with the general construction of flowers before the points of resemblance which have occasioned certain genera to be linked together to form orders, can be understood. [Illustration: FIG. 1.—STAMEN AND PISTIL.] It is thus evident that the first step towards a knowledge of systematic botany is to study flowers thoroughly, and few objects of study can be more interesting, whether we regard the elegance of their forms or the beauty and brilliancy of their colours. My readers may perhaps, however, be as much surprised as I was, to learn that the beautifully coloured parts of flowers are the least important; and that, as they only serve as a covering to the stamens and pistil, which are designed for the production of seed, they may be, and indeed actually are, wanting in a great many of what are considered perfect flowers. In examining a flower, therefore, it must be remembered that the production of seed is the object, for which all the curious contrivances we discover are designed. The germen or ovary (_a_ in fig. 1) is protected by a thick fleshy substance (_b_), called the receptacle or disk, which serves as a bed or foundation on which the other parts of the flower rest, and which is thence frequently called a thalamus or torus, both words signifying a bed. The ovary itself is hollow, and it is sometimes divided into several cells, each enclosing a number of ovules, which are afterwards to become seeds; but sometimes there is only one cell, and sometimes only one seed in each cell. The ovary is juicy and succulent when young, and very different from what it afterwards becomes when the seeds are ripe. Rising from the ovary in most flowers, is a long and slender stalk called the style (_c_), which supports a kind of head, called the stigma (_d_). The ovary, the style, and the stigma, constitute what is called the pistil; but the