the sensitive plant; a genus of the monœcia order, belonging to the polygamy class of plants.

This genus comprises shrubby and herbaceous plants, but mostly of the shrub kind, some trailing, others erect, all natives of the Indies, &c. retained here in stoves as great curiosities, particularly for the very singular sensibility of the leaves of some sorts, which on being touched, suddenly recede, contract, and fall down in a very wonderful manner: all of them garnished with pinnated leaves, and monopetalous, funnel-shaped, five-parted, polygamous flowers at the axillas and ends of the branches in clusters and spikes.

The name *mimosa* of this genus, signifies mimic, originating from the sensibility of the leaves, which, by their motion, mimic or imitate, as it were, the motions of animals.

To this genus Linnæus joins many of the acacias, and it comprises upwards of 40 different species; though not more than a quarter of them are common in the English gardens, or possess any particular merit either for curiosity or ornament, and none for use. 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; are mostly of the sensitive kinds, except the acacia sorts, which are motionless, as expressed under their proper heads, i.e. sensitive and humble kinds, and senseless kinds. The former of which are exceedingly curious plants in the very singular circumstance of their leaves receding rapidly from the touch; the leaves are winged, each composed of numerous small lobes, all of which on being touched, hastily run up close together; and in some sorts the footstalks and all are affected, so as instantly to fall downward, as if fastened by hinges.

**Shrubby, Sensitive, and Humble Kinds.**

They have all winged leaves, each wing consisting of many small pinnae; some only contract the lobes of the leaves and pinnae at the touch; others not only contract every part of their leaves, but their footstalks also suddenly drop downward; and for distinction sake, the former are called sensitive mimosas, and the latter humble sensitive; but the leaves of both sorts soon recover their usual position. The most remarkable species are,

1. Sen- 1. 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 bifurcated partial 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, recede 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 foliicles, 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 slothful mimosa. Hath undershrubby, procumbent, unarmed stems, branching two or three feet around; bipinnated leaves, of three or four pair of short, winged folioli; and at the axillas drooping spikes of pentandrous flowers, the lower ones castrated.

This sort recedes very slowly from the touch, only contracting its pinnae a little when smartly touched; hence the name slothful mimosa.

4. The asperata, or rough sensitive mimosa, hath a shrubby, upright, prickly, hairy, rough stem, branching four or five feet high, armed with short, broad, whitish spines; bipinnated, prickly leaves, of five or six pair of folioli, or wings, arranged opposite, having two thorns between each pair; and at the upper axillas globular heads of purple flowers, succeeded by short, flat, jointed pods, in clusters, spreading each way like a radius.

This is only moderately sensitive in its folioli, but not in the footstalks.

5. The punctata, or punctated sensitive mimosa, rises with a shrubby, upright, taper, punctated, or spotted, unarmed stem, branching erectly five or six feet high; bipinnated leaves, of four or five pair of long, winged folioles, having each about 20 pair of pinnae; and at the axillas 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 folioli, but quick in the motion.

Herbaceous Sensitive and Humble Kinds.

Of these sorts two are perennial of the trailing kind; and one is annual, of somewhat erect growth; have all winged leaves, with the wings formed of many small pinnae.

6. The viva,—perennial, or lively sensitive mimosa, hath herbaceous, trailing, unarmed, repent stems, very branchy, spreading widely around, rooting at the joints as they advance; conjugated pinnated leaves, with quadriradiated, roundish, partial lobes, or wings; and at the axillas globular heads of yellowish flowers; succeeded by short, flat, jointed pods.

This species is only sensitive in the folioli; but is the most lively of that kind, it being so susceptible that all the folioli recede rapidly from the least touch, whereby it has the distinctive appellation of vivacious, or lively mimosa.

7. The quadrivalvis,—perennial, or quadrivalve humble mimosa, hath herbaceous slender, quadrangular, prickly stems, branching and spreading all around, armed with recurved spines; bipinnated leaves of two or three pair of winged lobes, having each many pinnae; and at the axillas globular heads of purple flowers, succeeded by quadrivalvular pods.

This is of the humble sensitive kind, both leaves and footstalks recede from the touch.

8. The plena,—annual, or double-flowered sensitive annual mimosa, rises with an herbaceous, erect, round, unarmed stem, closely branching and spreading every way, three or four feet high; bipinnated leaves of four or five pair of winged lobes, of many pairs of pinnae; and at the axillas 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 folioli, but extremely sensible of the touch or air.

Shrubby Insensitive Kinds.

These are of the acacia kind, formerly a distinct genus, but now all species of Mimosa; but their leaves are destitute of motion or sensibility at the touch: there are about three noted species in the English gardens, all for the show.

9. The cornigera, or horned Mexican mimosa, commonly called great horned acacia, hath a shrubby, upright, deformed stem, branching irregularly, armed with very large, horned-like white spines, by pairs, connated at the base; bipinnated 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 farnesiana, or farnesian fragrant acacia, hath a shrubby stem, branching many feet high, armed with distinct spines; bipinnated leaves, having eight pair of partial lobes, or wings; and globular, clove-scented spikes of yellow sweet-scented flowers.

11. The nilotica, or nilotic true Egyptian acacia, hath an upright tree-stem, branching many feet high, armed with spreading spines; bipinnated leaves; and globular spikes of flowers, having footstalks. From the exudation of the leaves of this sort is procured the drugs called succus acaciae and gum-arabic.

Propagation, &c. These 11 species of mimosa are the most noted sorts in the English gardens; all the shrubby kinds are durable in root, stem, and branches; those of the perennial herbaceous kinds are also often abiding; but the annual sort always perish, root and branch, at the approach of winter. They are all natives of the Indies; and in this country require the continual shelter of a hot-house, or of a hot-bed of similar Mina lar temperature under frames and glasses; though they can hardly be supported alive in winter unless placed in a stove; so all the forts must constantly be kept in pots, and placed principally in that department, especially during the winter; nor will they succeed well in the open air in summer, except about a month during the greatest heat; but the sensitive and humble kinds, if exposed to the open air, even in the hottest days, will be deprived of their sensibility during the time they remain so exposed, therefore should always be kept under glasses, in a stove if possible; or in default of such a convenience, the plants might be raised from seed in spring in any common hot-bed under frames, &c., as directed for tender annuals, and continued constantly under the glasses, and thereby will afford pleasure all summer by the oddity of their sensitive foliage; however, to have them to remain in perfection the year round, some must be continued always in a stove, as before observed; for the warmer they are kept, the stronger will be their sensible quality: but for a particular account of this quality, see the article Sensitive Plant.

The propagation of all the forts, both sensitives and acacias, is by seed in spring in a hot-bed, or in the bark-bed in the stove; and some of the sensitive kinds also by layers and cuttings.