[58]

Mimosa pudica

November 1879.

a pot with young seedlings with 1 or 2 internodes above above hypoctyl (November 8th) developed was kept in study (cold weather) 57°-59° F. for 2 days in dark, Loss of Periodicity of Leaves in Dark except that it was looked at every hour on first days & every 3 or 4 days hours on 2d day as circumnutation of stem hypocotyl was observed— on evening of 2d day leaflets not properly asleep— Pot was then kept for 3 days in dark cupboards, & it show no signs of sleep in leaves & vy very slightly sensitive to strong touches. On next day Nov 13' filament with little [sketch] triangle fixed to pinnæ of 2 seedlings) (stem cemented cemented to little sticks) & movements traced on vertical glass for next 3 days — Of course there was some exposure to light as filament affixed &c — & at each observation, which often lasted 3' or 4' the seedlings were illuminated by 2 bright candles. At close of the 3 days leaflets & leaves continued to have a vestige of sensitiveness, but they had quite lost habit of sleeping. Nevertheless night & day both were circumnutating, but they had lost the proper periodicity of movement. — A (left) descended during 2 night (ie between 10° P.m & 7° am) & on 3d night moved laterally with little ascent; whereas they ought to ascend during night— During day During 2 days rose about midday instead of falling. B (right) moved laterally on one night with little ascent, on 2d night fell greatly on 3d night rose enormously: on first day-time circumnutated, but on whole fell & thus behaved normally— on 2d day circumnutated about nearly same spot— on 3d day fell enormously & this was normal movement — & next night rose enormously & this was normal movement — ((over)

[58v]

Conclusion — young plant kept in dark till all nyctitropic movement … & with only a vestige of sensitiveness retained — still circumnutated in plainest manner day & night in the dark, but the proper rate of movement lost — leaves sometimes descended or moved laterally during night— sometimes ascended during former instead of descending The amplitude of the periodical movement — vastly reduced

[Movement in plants, pp. 378-9]