PAPILIONACEI, in botany, a term applied to certain flowers, from their supposed resemblance to the figure of a butterfly. The term is applied also to the thirty-second order of Linnxus's "Fragments of a Natural Method." They are divided into two sections ; viz. those that have the filaments on the stamina distinct, and those with one set of united filaments. These plants, otherwise call ed leguminous, from the seed-vessel, which is that sort termed a legumen, are very different both in size and duration ; some of them being herbaceous, and those either annual or perennial ; others, woody vegetables of the shrub and tree kind, a few of which rise to the height of seventy feet, and upwards. The herba ceous plants of this order generally climb ; for being weak, and as it were helpless of;themselves, indulgent nature has either"provided them with tendrils, and even sharp-pointed hooks at their extremities, to fasten upon the neigh bouring trees or rocks, or endued the stalks with a faculty of twisting them selves for the purpose of support around the bodies in their neighbourhood. The pea, vetch, and kidney-bean, afford fa miliar examples of the appearances in question. The shrubs and trees this natural family are mostly armed with strong spines. The roots are very long, and furnished with fibres : some genera have fleshy tubercles, placed at proper intervals along the fibres. The stems are cylindric, as are likewise the young branches, which are placed alternately: those which climb twig themselves from right to left, in a direction opposite to the apparent diurnal motion of the sun. The bark of the large trees is extremely thick and wrinkled, so as to resemble a net with long meshes ; the wood is very hard in the middle, and commonly coloured or veined ; the alburnum is less hard, and generally of a yellow colour. The buds are hemispherical, without scales, and proceed from the branches a little above the angle which they form with the leaves. The leaves are alter nate, and of different forms, being either simple, finger-shaped, or winged. The flowers are hermaphrodite, and proceed either from the wings of the leaves, as in furze, liquorice, lupin, kidney-bean, &c. or from the extremity of the branch es, as in ebony of Crete, false acacia, tre foil, coral-tree, &c. The calyx is a peri anthium of one leaf, bell-shaped, branch ing out at the bottom, and cut on its brim or margin into five irregular divisions, or teeth, the lowermost of which being the odd one, is longer than the rest the other four stand in pairs, of which the uppermost is shortest, and stands furthest asunder. The bottom of the calyx is moistened with a sweet liquor, like honey, which may be deemed the nee tazium of these plants. The petals are
four or five in number, very irregular, and from their figure and position bear an obvious resemblance in most of the genera to a butterfly expanding its wings tbr flight. The stamina are generally ten in number. These are either totally distinct, as in plants of the first section ; or united by the filaments into one or two bundles, involving the seed bud, as in those of the second and third. In the latter case, where there are two sets of united filaments, one of the sets is com posed of nine stamina, which are united into a crooked cylinder, that is cleft on one side through its whole length. Along this cleft lies the tenth filament, or sta men, which constitutes the second set, and is often so closely attached to the large bundle, that it cannot be separated without some difficulty. The seed-bud is single, placed upon the receptacle of the flower, oblong, cylindrical, slightly compressed, of the length of the cylinder of the united stamina by which it is in volved; and sometimes, as in the coral tree, elevated by a slender foot-stalk, which issues from the centre of the ca lyx. The style is single, slender, and ge nerally crooked. In the pea the style is hairy, three-cornered, and keel-shaped above ; by which last circumstance ehief ly that genus is distinguished from the lathyrus, in which the style is plain. The stigma, or summit of the style, is gene-0 rally covered with a beautiful down, and placed immediately under the anthers, or tops of the stamina. The seed-ves sel in this order is that sort of pod term ed a legumen, which is Of an oblong figure, more or less compressed, with two valves, and one, two, or more cavi these cavities arc often separated, when ripe, by a sort of joints, which are conspicuous in the pods of the coronilla, French honey-suckle, horse-shoe vetch, bird's•fbot, bastard sensitive-plant, and scorpiurus : the seeds are generally few in number, round, smooth, and fleshy. Jointed pods have generally a single seed in each articulation. The seeds are all fastened along one suture, and not al ternately to both, as in the other species of pod termed siliqua.
The plants of this funny are in general mucilaginous ; from the inner bark flows a clammy liquor, which dries and hardens like gum : the, uice of others, as that of the liquorice, is sweet like sugar. Some of the plants are bitter, purgative, or emetic, and some are poisonous. They are, however, emollient, useful in the healing of wounds, and astringent. See Milne 's Botanical Dictionary.