[From the Greek, for mimic, as the irritable leaves imitate the sensibility of animals.]
Mimosa pudica, - Sensitive Plant. - A native of Brazil, and well-known for the extreme irritability of the leaves, which, when touched, immediately fold themselves together, and the petiole at the same time droops. The cause of this motion has been the subject of many curious speculations. "The most irritable part of the plant is in the foot-stalk, between the stem and the leaflets.
During the night, they remain in the same state as when touched in the day-time; yet, if touched then, will fold their leaves still closer."
"Miller, in one of the earlier editions of his Dictionary, speaks of a Calabrian philosopher, who was driven mad by considering the mysterious nature of this plant; 'just,' continues he, 'as Aristotle is said to have flung himself into the sea, because he could not comprehend the ebbing and flowing thereof.' "
When any of the upper leaves are touched, if in falling they touch those below them, these also will contract and fall, so that by touching one another, they will continue to fall for some time.
Many years since I was greatly interested in a bed of Sensitive Plants, which filled a frame four feet by ten. I set out the youngs plants in a hot-bed, where the heat was nearly spent, some time in May, about eight inches apart. The glass was kept on till the middle of June, when the plants were fully exposed. They continued to flourish until the bed was completely filled. It was a source of great amusement to myself and visitors to irritate this mass of plants, which was easily done, by giving the frame a gentle kick. The effect would be to cause every plant to drop its foot-stalks and close its leaves. If it was very warm, the foot-stalks would gradually rise, and the leaflets resume their expanded state; the plant is most irritable in the greatest heat. Dr. Darwin thus characterizes it:-
"Weak with nice sense the chaste Mimosa stands, From each rude touch withdraws her tender hands i Oft as light clouds o'erpass the summer glade, Alarmed, she trembles at the moving shade, And feels alive through all her tender form, The whispered murmurs of the gathering storm; Shuts her sweet eye-lids to approaching night And hails with freshened charms the rising light.'.'
In cloudy damp weather, or on the approach of storms, or in the damp of the evening and through the night, the foot-stalks fall, the leaflets close, and the plant appears to be in a state of repose. It is an annual, which, if started in a hot-bed, will flourish in the borders during the summer, but looses its sensitiveness in a great measure as cold weather approaches.
[From the Greek for ape, in allusion to the gaping corolla.]
The species are showy plants of the easiest culture in almost any soil or situation. They are perennials in the green-house, where they are easily propagated from cuttings or from seed. In the open ground they are annuals, flowering profusely from seed the same season. I have known them to stand through the winter, when covered with ice and snow most of the season. The seeds are very small, and require considerable attention to get them to vegetate. I have known seeds, self-sown in autumn, to come up freely in the spring, commencing to flower in June, and continuing in bloom till October. They succeed best in a moist soil, partially shaded.
From this species, sometimes called M. rivularis, a great number of beautiful varieties have been produced. The flowers are tubular, with wide-spreading segments; the ground color, all shades of yellow, from light straw to deep-orange, beautifully spotted or blotched with crimson or scarlet. On some varieties there is a large blotch or spot on each segment of the corolla, while the throat of the plant is beautifully spotted or mottled. It is a flower very much given to sporting. The following remarkable account of the success in the cultivation of this plant is detailed in an English paper:-
"This plant delights in a rich, moist soil, mixed with sand, and if it be a little shady it is beneficial; the colors of the flower are better, and the plant more vigorous. A free supply of water is necessary, in order to grow it successfully. I have had a single plant grow three feet and one-half high, and be six feet in circumference, producing a vast profusion of flowers, most amply repaying the little extra attention paid to its culture. When I obtained this plant at first, I was instructed to grow it in a small, shallow pond, keeping the roots immersed in water. I was told it would there succeed far better than by any-other method; but in this particular I find it very much to the contrary. A soil as above described, and a good supply of water in dry weather, are all that is required. I had a plant grown in a pot this summer, the size above particularized. The species and all its varieties are readily increased by taking off rooted shoots, or by cuttings. Seed sown in spring, and the plants pricked out into a bed of rich soil, will flower by July, and continue through the season. The impregnation of these kinds, with any or all of the others, produces a pleasing and interesting variation of flowers." A variety of this, called M. variegatus, is a delicate flowering one, and other varieties have been called species under the names of M. punctatus, M. speciosus, M. rubinus, etc.
This is another very ornamental species, with brilliant scarlet flowers, with varieties having rose or orange-colored blossoms. It requires the same treatment as the other species, and is equally rapid in its growth. I have not, however, ever raised plants as large as have been described.
This well-known Mimu-las is cultivated on account of the musky odor of the plant, rather than for its flowers, which are yellow and much smaller than in most of the species. It delights in a rich soil, and if the summer proves dry, the plant requires a free supply of water; if deprived of this, it will be weakly, and produce but few flowers. When grown in such a soil, and well attended with water, a plant has been known to grow two feet high. To effect this, the suckers, as fast as they appeared, were pinched off, so that the strength of the plant was thrown into a single stem; the result was, an upright pyramidal plant, two feet high, clothed with blossoms from bottom to top.
The general" habit of the plant when left to itself, is weak and trailing. It is, therefore, a very pretty plant for a hanging vase. The shoots will push rapidly, and hanging gracefully down the sides with its numerous yellow flowers, presents a very pleasing appearance, perfuming the air to a considerable distance.
All the varieties and species require the same care in cultivation as has been described; always remembering that in our climate the mid-summer's sun is most too powerful for them if fully exposed to its influence. A situation, therefore, should be selected where the plants will have sun only in the morning a few hours, and in the afternoon the same.