I would advise such of my readers as are anxious to turn the preceding pages to account, to procure as many of the plants I have described as possible, and to compare them with each other, and with any other plants belonging to the order Ranunculaceæ that they can obtain. Those who have access to a botanic garden will have no difficulty in finding the names of the genera included in the order; and those who have not this advantage, must consult Don’s edition of Sweet’s Hortus Britannicus, or any other catalogue in which the plants are arranged according to the Natural System. When a number of specimens have been collected, the student will be surprised to see how many points of resemblance exist between them. The stems of all, when cut, will yield a watery juice; which is always acrid, though some of the plants are more poisonous than others. The stamens will be found to be always numerous, and always attached to the receptacle below the carpels; and the anthers are generally adnate, that is attached to the filaments from one end to the other (see p. [12]). The carpels are in most cases numerous, and either distinct, or adhering in such a manner as to show plainly the line of junction between them; they are also always one-celled, whether one or many-seeded, and generally either caryopsides (see p. [24]), or follicles (see p. [28]). The leaves are generally divided into three or five lobes, each of which is cut into several smaller divisions; and the petioles or leaf-stalks are very frequently dilated at the base, and sheathing the stem. In most cases, the flowers are of brilliant colours, several of them being cup-shaped, and many with the calyx more ornamental than the corolla. The seeds will generally keep good for several years; and several of them, particularly those of the kind called caryopsides, when sown, are often a long time before they come up.
CHAPTER II.
THE ORDER LEGUMINOSÆ: ILLUSTRATED BY THE SWEET-PEA, THE RED CLOVER, ACACIA ARMATA, THE SENSITIVE PLANT, THE BARBADOES FLOWER-FENCE, THE CAROB-TREE, THE TAMARIND, THE SENNA, THE GLEDITSCHIA, THE LOGWOOD, THE JUDAS-TREE, AND THE KENTUCKY COFFEE-TREE.
This order is a very numerous one, containing above three hundred genera, and including several highly important plants, both for food and commerce. As examples of the utility of the Leguminosæ for food, I need only mention the pea and bean, and all their numerous allies; and as examples of their importance in medicine and the arts, I may enumerate senna, liquorice, the tamarind, gum-arabic, and logwood. Among the ornamental plants belonging to this order are, the Laburnum, the Furze or Gorse, the Robinia or False Acacia, the true Acacias, the Sensitive Plant, and the Barbadoes Flower-fence. It will be seen by this enumeration, that the flowers of the Leguminosæ differ from each other nearly as much as those of Ranunculaceæ; but when in seed, they are all easily recognised by their seed-vessels, which are always legumes, that is, bearing more or less resemblance to the pod of the common pea. To aid the memory in retaining the great number of genera included in this order, various methods have been devised of re-dividing it; and of these I shall adopt the newest, which is also the simplest, by which they are arranged in three tribes, according to their flowers.
TRIBE I.—PAPILIONACEOUS FLOWERS.
The flowers of this tribe are called Papilionaceous;
Fig. 13.—Flower, pod, and tendril, of the Sweet-pea. because Papilio is the scientific name of a genus of butterflies, which they were supposed to resemble. The type of this tribe may be considered the flower of the sweet-pea (Lathyrus odoratus), which has a small green calyx, cut into five deep notches, but not divided into regular sepals. (See a and b in fig. 13.) The corolla is in five petals, the largest of which (c) stands erect, and is called the vexillum or standard; below this are two smaller petals (d), which are called the algæ or wings; and below these are two petals, joined together so as to form a kind of boat (e), which are called the carina or keel, and which serve as a cradle for the stamens and pistil. There are ten stamens, nine of which have the lower half of their filaments growing together, so as to form a fleshy substance at the base, as shown in fig. 14 at f, and the other (g) is free.