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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 8° 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 10° 30' & 1° 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 1° 30 during sleep, & in other case 10°. The petiole of orbicular primary leaf rose rose in one case 5° 30', & in other case fell 3° 30', so say nothing about petioles of young orbicular leaves