the sensitive plant: A genus of the polygamia order, belonging to the monoecea class of plants; and in the natural method ranking under the 33d order, Lomentaceae. The hermaphrodite calyx is quinquedentate; the corolla quinquefid; there are five or more stamens, one pistil, and a legumen: The male calyx is quinquedentate; the corolla quinquefid; with five, ten, or more stamens.
The name mimosa signifies "mimic;" and is given to this genus on account of the sensibility of the leaves, which, by their motion, mimic or imitate, as it were, the motion of animals. See Sensitive Plant.
To this genus Linnaeus joins many of the acacias; and it comprises near 60 different species, all natives of warm climates. Of the sorts cultivated here in our stoves, &c., some are of the shrub and tree kind, and two or three are herbaceous perennials and annuals. The sensitive kinds are exceedingly curious plants in the very singular circumstance of their leaves receding rapidly from the touch, and running up close together; and in some sorts the footstalks and all are affected, so as instantly to fall downward as if fastened by hinges, which last are called humble sensitives. They have all winged leaves, each wing consisting of many small pinnae.
In the Systema Vegetabilium, this genus, including the mimosas properly so called, and the acacias, is divided into several sections, distinguished by the figure, situation, and arrangement, of the leaves; as, simple, simply-pinnated, bigemino and tergeminous, conjugate and pinnated, doubly pinnated. The following are the most remarkable
Species, with their properties. 1. The Sensitiva, or common sensitive humble plant, rises with an undershrubby prickly stem, branching six or eight feet high, armed with crooked spines; conjugated, pinnated leaves, with bijugated pinnate lobes or wings, having the inner ones the least, each leaf on a long footstalk; and at the sides and ends of the branches many purple flowers in roundish heads; succeeded by broad, flat, jointed pods, in radiated clusters.—This is somewhat of the humble sensitive kind; the leaves, footstalks and all, receding from the touch, though not with such facility as in some of the following sorts.
2. The Pudica, or bashful humble plant, rises with an undershrubby, declinate, prickly stem, branching two or three feet around, armed with hairy spines; pinnated, digitated leaves, each leaf being of five or more long folioles, attached by their base to a long footstalk, and spread out above like the fingers of a hand; and at the sides and ends of the branches roundish heads of greenish white flowers, succeeded by small jointed prickly pods.—This is truly of the humble sensitive kind; for by the least touch the leaves instantly recede, contract, close, and together with the footstalk quickly decline downward, as if ashamed at the approach of the hand.
3. The Pernambucana, or Pernambuco bashful mimosa, has undershrubby, procumbent, unarmed stems, branching two or three feet around; bipinnated leaves, of three or four pair of short, winged folioles; and at the axils drooping spikes of pentandrous flowers, the lower ones castrated.—This species recedes very slowly from the touch, only contracting its pinnae a little when smartly touched; hence the name bashful mimosa.
4. The Alperata, or Panama sensitive plant. Of this curious species, which has been well described by Dr Browne (but not figured), there is a good figure in the Reliquiae Houtonianae published by Sir Joseph Banks. It grows in moist places, and by the sides of rivulets, in the parishes of St James and Hanover, Jamaica. It seldom rises above three feet in height; but its slender branches extend considerably on the neighbouring bushes. It is armed with crooked, sharp, spines; so thickly set on the trunk, branches, and leaves, that there is no touching it with safety. But the plant has a beautiful appearance; the flowers are yellow and globular, growing at the extremity of the branches. The pods are hairy, brown, and jointed; each containing a small, flat, and brown seed. The leaves are numerous, small, and winged; next to those of the mimosa pudica, they are the most irritable; contracting with the least touch, and remaining so for several minutes after. This species would form a good hedge or fence round a garden; and by being trimmed now and then by a cutlass or gardener's scissor, may be easily kept from spreading.
5. The Punctata, or punctated sensitive mimosa, rises with a shrubby, upright, taper, spotted, unarmed stem, branching erectly five or six feet high; bi-pinnated leaves, of four or five pair of long winged folioles, having each about 20 pair of pinnae; and at the axils and termination of the branches oblong spikes of yellowish decandrous flowers, the inferior ones castrated; succeeded above by oblong seed-pods. This sort, though naturally shrubby and perennial in its native soil, yet in this country it sometimes decays in winter. It is only sensitive in the foliole, but quick in the motion.
6. The Viva, lively mimosa, or smallest sensitive weed, has many creeping roots, and spreads itself so as to cover large spots of ground. It rises at most to two inches, has winged leaves, with numerous small pinnae. The flower is globular, of a bluish colour, and grows in clusters from the axil: these are followed by little, short, hairy, pods, containing smooth shining seeds. This is the most sensible of all the mimosas, the pudica not excepted. By running a stick over the plant, a person may write his name, and it will remain visible for ten minutes.
7. The Quadrivalvis, perennial, or quadrivalve humble mi- MIMOSA
The mimosa, has herbaceous, slender, quadrangular, prickly stems, branching and spreading all around, armed with recurved spines; bipinnate leaves of two or three pairs of winged lobes, having each many pinnae; and at the axils globular heads of purple flowers, succeeded by quadrivalvular pods. This is of the humble sensitive kind, both leaves and footstalks receding from the touch.
8. The Plena, annual, or double-flowered sensitive mimosa, rises with an herbaceous, erect, round, unarmed stem, closely branching and spreading every way, three or four feet high; bipinnate leaves of four or five pair of winged lobes, of many pairs of pinnae; and at the axils and termination of the branches spikes of yellow pentandrous flowers, the lower ones double; succeeded by short broad pods. This annual is only sensitive in the foliola, but extremely sensible of the touch or air.
9. The Cornigera, or horned Mexican mimosa, commonly called great horned acacia, has a shrubby, upright, deformed stem, branching irregularly, armed with very large, horn-like white spines, by pairs, connated at the base; bipinnate leaves thinly placed; and flowers growing in spikes. This species is esteemed a curiosity for the oddity of its large spines, resembling the horns of animals, and which are often variously wreathed, twisted, and contorted.
10. The Fariniflora, or fragrant acacia, grows in woodlands and waste lands in most parts of Jamaica; rising to 25 or 30 feet, with suitable thickness. The bark of the trunk is brown and scaly, the branches are alternate. It is adorned with bipinnate leaves of a bright green colour; and yellow globular flowers from the axilla, of a fragrant smell. The pods are about three inches long, and half an inch broad: they are of a light brown colour, smooth, compressed, and contain five or six smooth flat seeds. Formerly the flowers of this tree were used as an ingredient in the theriaca andromachi of the old dispensatories. The tree is sometimes planted for a hedge or fence round inclosures; and the timber, though small, is useful in rural economy.
11. The Arborea, or wild tamarind tree, is common in all the woodlands, and especially near where settlements have been made, in Jamaica. It rises to a considerable height, and is proportionably thick. The timber is excellent, and serves many purposes in rural economy: it is of the colour of cedar, pretty hard, and takes a good polish. The leaves are numerous; the flowers globular and white. The pods are about a foot in length, of a fine scarlet colour; when they are ripe they open and become twisted. The seeds then appear; they are oblong, smooth, of a shining black, and quite soft. On the whole, from the leaves, flowers, and pods, this tree exhibits a singular and beautiful contrast. With us this plant is raised in hot-houses; but it appears, that with a little pains it may be made to grow in the open air. A good sizeable tree of this sort grew in the garden of the late Dr William Pitcairn, at Islington, near London.
12. The Latifolia, shag-bark, or white wild tamarind. This excellent timber tree is very common in Jamaica, and rises to a moderate height and good thickness. The trunk is rough and scaly: The leaves are numerous, of a rhomboidal figure, and yellowish cast. The flower-spikes are from the axilla; their colour is yellow. The seed-vessels are flat, jointed, and twisted. The seeds are of the bigness of a vetch, white, and finely streaked with blue.
Of this tree there is a variety which some botanists call M. serpentina. The chief difference is in the leaves, which are smaller, and of a shining dark green.
13. The Lebeck, or ebony tree. This is a native of the East Indies, but raised from seeds in Jamaica and St Vincent's. It is figured, though not accurately, by Plukenet, Tab. 331, fig. 1. To what height this tree grows, we cannot yet say; but it must be of a considerable thickness if it be the ebony we have in use here. Time will soon determine this, as the few plants in the islands are reared with great care by Dr Dauver in Jamaica, and Mr Alexander Anderson in St Vincent's.
14, 15. The Cinerea — Pinnata? Calhaw bushes. These species are common about Kingston and Spanish town Jamaica, and rise by slender trunks to about 20 feet.
Dr Roxburgh of Madras, amongst a number of useful discoveries, has found the lac insect on this species of mimosa*. We have seen the native gum-lac* See Aff on one of the small twigs, and a specimen of the plant in the collection of a gentleman here. The plant is a variety of the cinerea, and appears rather to be the M. pinnata, Lin. It is to be hoped, that in a short time the useful insect just mentioned may be transported from Asia to the West Indies, where this gum, or rather wax, may be also produced.
16. The Scandens, cacoon, or mafootoo wyth (Gigalobium scandens), Browne's Jam. p. 362. Pfeiffer maximus perennis, Sloane's Cat. 68. Pericin Kaku-valli, H. M. viii. T. 32, 3, 4.) This species of mimosa is frequent in all the upland valleys and woodlands on the north side of Jamaica. It climbs up the tallest trees, and spreads itself in every direction by means of its cirri or claspers, so as to form a complete arbour, and to cover the space of an English acre from one root. This circumstance has a bad effect on the trees or bushes so shaded. Light, air, and rain (so necessary for all plants), being shut out, the leaves drop off, the tree gradually rots, and the limbs fall down by the weight of this parasite.
Several authors have mentioned the cacoon; but their descriptions of the plant, and particularly the figures, are erroneous. On that account we have given a figure from the herbarium of a gentleman long resident in Jamaica; and the following are the characters, transcribed from his field notes.
Folia conjugata. Petioli communis longi oppositi cirrho terminali. Pinnae quadrifluge vel duodecim jugae, oblonge apice obtusa nitide utrinque glabrae. Cirrus longus contortus apice bifidus. Spica axillares erectae, longiflumeae, multiflorae floribus parvis, colore viride flavo. Calyx quinquedentatus minus. Corolla pentapetala, erecta, parva. Filamenta numeroa, e basi corollae, et eodem longitudine. Antherae globose erectae. Stylos filiformis, tortus, longitudine itaminum. Stigma simplex. Legumen maximum, lignosum durum, 5 vel 8-pedale longum et 4-5 unciarum latitudine, varie contortum, compressum, bivalve. Semina plura, circiter decem vel quindecim numero, orbiculata, subcompressa, cortice duro, nitido-tusco. Hilo nigro breve.
The roots of this plant run superficially under the ground or herbage. The trunk is seldom thicker than a man's thigh, and sends off many branches, with numerous shining green leaves, each of which terminates in a tendril or clasper, that serves to fasten it to trees or bushes. The flower-spikes are from the axil: they are slender, and the florets on them small and numerous. The pod is perhaps the largest and longest of any other in the world; being sometimes eight or nine feet in length, five inches broad, jointed, and containing 10 or 15 seeds. These seeds are brown, shining, flattened, and very hard, and called cocoons. They are the same mentioned in the Philosophical Transactions, n° 222, page 298, by Sir Hans Sloane, as being thrown ashore on the Hebrides and Orkneys. This happens in the following manner: The seeds or beans fall into the rivers, and are conveyed to the sea. The trade-winds carry them westward till they fall into the gulf stream, which forces them northward along the coast of America and Bahama islands. As the winds blow frequent and strong from America, these seeds are driven to the eastward, till at length they are thrown ashore and left with the tide as aforesaid.
This bean, after being long soaked in water, is boiled and eaten by some negroes; but, in general, there seems to be no other use made of it than as a sort of snuff-box.
17. The Catechu, according to Mr Ker†, grows only to 12 feet in height, and to one foot in diameter; it is covered with a thick rough brown bark, and towards the top divides into many close branches: the leaves are bipinnate, or doubly winged, and are placed alternately upon the younger branches: the partial pinnae are nearly two inches long, and are commonly from 15 to 30 pair, having small glands inserted between the pinnae: each wing is usually furnished with about 40 pair of pinnae or linear lobes, beset with short hairs: the spines are short, recurved, and placed in pairs at the bases of each leaf: the flowers are hermaphrodite and male, and stand in close spikes, which arise from the axil of the leaves, and are four or five inches long: the calyx is tubular, hairy, and divides at the limb into five oval pointed segments: the corolla is monopetalous, whitish, and of the same form as the calyx, but twice its length: the filaments are numerous, capillary, double the length of the corolla, adhering at the base of the germen, and crowned with roundish antherae: the germen is oval, and supports a slender style, which is of the length of the filaments, and terminated by a simple stigma: the fruit, or pod, is lance-shaped, brown, smooth, compressed, with an undulated thin margin; it contains six or eight roundish flattened seeds which produce a nauseous odour when chewed. From this tree, which grows plentifully on the mountainous parts of Indostan, where it flowers in June, is produced the officinal drug long known in Europe by the name of terra japonica; for the history and preparation of which, see the article Terra Japonica.
18. The Nilotic, or true Egyptian acacia, rises to a greater height than the preceding: the bark of the trunk is smooth, and of a grey colour; that of the Mimosa branches has commonly a purplish tinge: the leaves are bipinnate, and placed alternately; the partial pinnae are opposite, furnished with a small gland between the outermost pair, and beset with numerous pairs of narrow elliptical pinnae, or leaflets: the spines are long, white, spreading, and proceed from each side of the base of the leaves: the flowers are hermaphrodite and male; they assume a globular shape, and stand four or five together upon slender peduncles, which arise from the axil of the leaves: the calyx is small, bell-shaped, and divided at the mouth into five minute teeth: the corolla consists of five narrow yellowish segments: the filaments are numerous, capillary, and furnished with roundish yellow antherae: the germen is conical, and supports a slender style, crowned with a simple stigma: the fruit is a long pod, resembling that of the lupin, and contains many flatish brown seeds. It is a native of Arabia and Egypt, and flowers in July.
Although the mimosa nilotica grows in great abundance over the vast extent of Africa, yet gum arabic is produced chiefly by those trees, which are situated near the equatorial regions; and we are told that in Lower Egypt the solar heat is never sufficiently intense for this purpose. The gum exudes in a liquid state from the bark of the trunk and branches of the tree, in a similar manner to the gum which is often produced upon the cherry-trees &c. in this country; and by exposure to the air it soon acquires solidity and hardness. In Senegal the gum begins to flow when the tree first opens its flowers; and continues during the rainy season till the month of December, when it is collected for the first time. Another collection of the gum is made in the month of March, from incisions in the bark, which the extreme dryness of the air at that time is said to render necessary. Gum arabic is now usually imported into England from Barbary; not packed up in skins, which was the practice in Egypt and Arabia, but in large casks or hogsheads. The common appearance of this gum is well known; and the various figures which it assumes seem to depend upon a variety of accidental circumstances attending its transmutation and concretion. Gum Arabic of a pale yellowish colour is most esteemed; on the contrary, those pieces which are large, rough, of a roundish figure, and of a brownish or reddish hue, are found to be less pure, and are said to be produced from a different species of mimosa (M. Senegal); but the Arabian and Egyptian gum is commonly intermixed with pieces of this kind, similar to that which comes from the coast of Africa near the river Senegal.
Gum-arabic does not admit of solution by spirit or oil, but in twice its quantity of water it dissolves into a mucilaginous fluid, of the consistence of a thick syrup; and in this state answers many useful pharmaceutical purposes, by rendering oily, refrinous, and pinguisous substances, miscible with water. The glutinous quality of gum Arabic is preferred to most other gums and mucilaginous substances, as a demulcent in coughs, hoarsenesses, and other catarrhal affections, in order to obtund irritating acrimonious humours, and to supply the loss of abraded mucus. It has been very generally employed in cases of ardor urinis and stranguria; Mimosa: but it is the opinion of Dr Cullen, "that even this mucilage, as an internal demulcent, can be of no service beyond the alimentary canal." See farther the article Gum Arabic.
19. The Senegal is a native of Guinea, and was some time ago introduced into Jamaica. Dr Wright tells us, he saw both this and the mimosa nilotica, of the size of a cherry tree, growing at Dr Pateron's in the parish of Hanover, Jamaica. The flowers are globular, yellow, and fragrant. The pods are brown, and of the size of a goose-quill. The tree, on being wounded, exudes gum arabic, though in less quantity, and less transparent, than that of the shops, which is obtained from the mimica above described.
There are above 40 other species characterized in the Systema Vegetabilium.
On Plate CCCXII, is figured a new species, of an uncommon size, mentioned by Mr Paterson in his Travels among the Hottentots, but not particularly described. Like several of the other mimosas, it produces gum, which is considered by the natives as a peculiarly delicate species of food: the leaves and lower points of the branches seem to constitute the principal aliment of the camelopardalis; and, from the extent of its boughs, and the smoothness of the trunk, it affords a sufficient defense to a species of gregarious bird against the tribe of serpents and other reptiles which would otherwise destroy its eggs. See the article Loxia.
Mr Bruce describes two plants which seem referable to this genus; the one named ergett el dimmo, the other ergett el korne.
The former, in our author's opinion, should be named mimosa fanguea; its name in the Abyssinian language signifies the bloody ergett, and derived, as he supposes, from its being partly composed of beautiful pink filaments. When the blossoms are fully spread, the upper part of them consists of yellow curled filaments, and the under part of pink filaments of a similar shape. In its unripe state, that part which afterwards becomes pink is of a green colour, and composed of tubercles of a larger size, and more detached than those which afterwards produce the yellow filaments; the latter being smaller, and closer set together: the leaves are of the double-pinnated kind.
The name of the other species, in the Abyssinian language, signifies the horned ergett; which our author supposes to be given it on account of the figure of the pods. The flower very much resembles that of the acacia vera in size and shape, excepting that it is attached to the branch by a strong woody stalk of considerable length, which grows out at the bottom of the branch bearing the leaves, and is sheltered as in a cage by the lower part of it. The branches are all covered with short, strong, and sharp-pointed thorns, having their points inclined backwards towards the root. The pods are covered with a prickly kind of hair, which easily rubs off with the fingers, sticks to them, and gives a very uneasy sensation. They have thirteen divisions; in each of which are three hard, round, and shining seeds, of a dusky brown colour.
Both of these shrubs shut their leaves on the coming on of the violent rains in the wet season, and never fully expand them till the dry season returns.