Arizona weekly enterprise., 1888-01-21
SENSITIVE PLANTS.
Humility as Typified by the Meek, Gentle
 and Shrinking MimoSa.

The sensitive plants Mtnl0SU pudac0 and SeaSitiUG are among the most in- teresting products of the vegetable kingdom Nearly every one has seen these graceful and humble children of nature, and touched thelr tender, shrinking leaves with an experiment. ing hand; but very few have taken the trouble to examine them as they deserve. The botanist-restrained perhaps, by pity for their humility. seems to have seldom used his section- knife and forceps on them; and while other wonders of the plant-world have been fully investigated. the Mimosa remains almost unknown.
 The Mimosa is a native of Brazil; but it has long been an occupant of our greenhouses. In grace of form and beauty of color. no other plant surpasses it. Its tender leaflets shrink and droop at the slightest touch, like a meek spirit from the worlds gaze
 Its graceful feather-shaped leaves, in common with most similarly shaped leaves of the Leqwmtsoso or pea tribe, to which botanical order the Mimosa belongs. close at the approach of dark
 ness; and it's extreme sensitiveness is
 but an extension of this peculiar plant 1 sleep. Wind or rain causes its leaves | to close and its stalks to droop< When
 suddenly shaken by the wind, the leaf ! Jets and leafstalks fall simultaneously.
 The same effect is seen when plant
 is put into darkened room
 during the day. A strong
 light from a psrsain lamp was placed near two plants of MinoSG
 se'asitiUa at night. After thirty min
 utes had elapsed. one of the plants,
 the more vigorous of the two. opened
 its leaves partially; tie other or less
 robust plant showed almost no feeling.
 A plant which had been on an exhibi-
 ton table at fower-show for two
 days, and which was noticed to re-
 ceive constant attention from some
 children present. was found to have
 lost much of its excita bility, and did
 not again return to its normal state,
 though the plant continued in a seem-
 ingly healthy condition for about n
 month afterward Two leaves which
 were nearest the edge of the table and consequently oftenest touched by the children's fingers, were completely ' The vapor of chloroform, prussic
 acid, ether and nicotine irritates the leaves, ana in some cases destroys their mobility. A little chloroform dropped on the base of leafstalk causes it to droop; and the leaflets.
 beginning at the apex. and proceeding to the base of the leaf, close in success sion. A plant, the leaves of which were heavily chloroformed several 3 times, withered and died in few
 days. The suns rays concentrated in
 lens and thrown on a leaf cause it tC
 contract quickly.
 The cause of the peculiar exeitability of sensitive plants, and the center 0t 2 its action, are still undetermined. , Various theories have been ad duced to explain them. Dr.
 Dutrochet's theory is most favored e by botanists of the present day f His explanation is, that ''the prin ci- . pal point of mobility exists in the ift- e tie swellings situated at the basis ot t the common and partial leaf stalks. : This swelling, or intumescence, is |, formed of delicate cellular tissue. , Il He says that ''the agency .producins the mobility is in the ligneous part O :, the central system of this intumes cence. and in certain tubes supplied i with nervous corpuscles serving fol a the transmission of the sap"
 > Dr. Balfour says: Tn the swell q ings at the bases of the leaf stalk tho
 vascular bundles are disposed in j. circle near the periphery, and may b '- concerned in the leaf movements > Mechanical and chemical stimuli ar C supposed to act by inducing altera u tions in the contents of the vessels an, 1T cells"
 o These theories are unsatisfactory, ant Il there is still much room for furthc I investigation into the origin of tn q peculiar phenomena seen in tn i. Mimosa. The manner in which if closes its stalks and leaves at the ap ,r proach of darkness is very interest n ing. As the gloaming gently fall
 round the plant, the leaflets move up d wards towards each other till the l- touch; the secondary leaf-stalks COB Is verge and slowly droop till they ar It nearly parallel to the main leaf-stalks ot which, in their turn. fall till the IT u, point to tho ground. Thus gently an 1 silently it folds itself to sleep at tn
 close of day, and rests till the light C l. morn awakes it to re newed grace an
 beauty. = Chambers Journal.