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Pontedria– Highland of St. Catharina. F. Muller

Circumnutation of leaf

July 2d an oldish leaf which with petiole was 8 inches in length first observed, under skylight with filament attached to mid-rib, & highly inclined, so tracing on vertical glass much magnified— leaf first circumnutated & then during following night & day moved in ma same general direction from some unknown cause, but on 2d day so zig-zag that clearly cir was circumnutating.

July 2d in evening of same day filament was fixed in same manner differently & transversely across apex of leaf of younger leaf, 7 1/2 inches high., with apex 16 1/4 from vertical glass. [sketch]

Therefore tracing greatly magnified, & movement consequently very small — Yet seeing way it travelled back on July 3d, there can be no doubt circumnutated slightly.—

(Temperature under skylight probably too low for much growth & movements: on 2nd 17 1/2 –18° C. on 3d 17° — on morning of 15th only 16° C. —

(A filament was fixed across the apex of a a moderately young arrow shaped leaf, 7 1/2 inches in height, & its movement was traced during 42 1/2 hour, See Fig on commencing on first the evening, when tracing was begun, the leaf & during the night the leaf descended; on the next morning it ascended in strong marked zig-zag line & descended again in the evening & during the night. — These movements, therefore seem to be periodical, but some little doubt is thrown on this conclusion, because as it a rather a older leaf

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