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Melilotus Italica. Sleep

Oct 3d 1877.

Plants in pots now nearly 36 inches high & in full flower.— I do not believe, that cotyledons sleep.— First leaves orbicular single — vertical in sleep. Some young plants 5-6 inches high late seedlings — leaves slept quite normally — ie. terminal leaflet vertical & turned to one side & lateral leaflets toward turned much towards apex of leaf & approached each other. But But at 8º 30' long after plant had gone to sleep & young plants well asleep, not one (& I examined scores of leaves) had terminal leaflet turned too one side, but vertical: the lateral leaflets had likewise twisted on one axes so as to become vertical, but had not moved towards apex of leaf, so that sleep position very different. At 10º 30' & 1º P.m. The terminal leaflets had very slightly turned to one side, so that no longer in quite same line with main petiole & lateral leaflets had approached each other by a trifle; yet position very far from normal. The young plants in their sleep thus show an embryological character like gorze &c. On old plants the older & basal leaves go to sleep — I measured angle of stem beneath & main petioles of one of old plants — (one of uppermost leaves) & no change in this angle during sleep.—

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[113v]

M. Italica

(a)

Oct 4th I also measured angle between stem & petiole of highest leaf on 2 of young small plants, when asleep & awake — These leaves stood almost vertically very highly inclined: in one case the leaf rose 1º 30 during sleep, & in other case 10º. The petiole of orbicular primary leaf rose rose in one case 5º 30', & in other case fell 3º 30', so say nothing about petioles of young orbicular leaves