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July 1878.

Trifolium subterraneum

(Circumnutation & sleep of terminal Leaflet)

Some fine vigorous plants in a pot just beginning to flower.— Petiole secured close to base of 3 leaflets, & filament observed fixed to midrib of youngish terminal leaflet, which faced almost directly vertical [sketch] glass under skylight. Temp. on 4th 16° to 16° 3/4' C.—

Length of leaflet with its sub-petiole .68 of inch. — (Distance of tip from vertical glass 3 7/8 of inch— distance of base of leaflet 4.7 of inch This applies to July 4th)

(July 3d pot not knowing how wonderfully the leaflet circumnutates up & down independently of the great nocturnal movement, pot placed at first 7 or 8 inches from glass & the tracing so gigantic of no use for copying; it moved, however, between 8° a.m & 6° P.m. 3 times up & 2 times down)

July 4th pot moved nearer (very near glass ie 3 7/8 of inch (see above) & Tracing carefully made.

Between 6° 45' a.m. & 6° P.m. it moved 3 times down & 3 times to great distances, & all this movement independent of the nocturnal movement, which is evidently evidently & manifestly at an exaggeration late in evening of one of the ups & downs swings.— We here see clearly that the movement is circumnutation, as the ascending & descending lines do not coincide.— I was so much struck with the wonderful amt amount of movement, that George Carefully measured & calculated angles & amt amounts — During the day, (independently of nocturnal movement, during which

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Trifolium subterraneum

the terminal leaflet not only stands vertically — so cd not be traced but curls over) the leaf rose 50° degrees above the horizontal line & sank 48° beneath do.— The tip of the leaf in the 2 extreme positions, during day-time was 1.03 inches apart.— In the tracing the distance of these 2 points is 10.78 inches, so that tracing about 10 1/2 exaggerated.─