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July 10' 1878

Smithia Pfundii

Circumnutation of downward Hooked terminal shoot.—

(Stem secured to stick close beneath the bowed part.)

This African Leguminous marsh or aquatic plant always kept in Hot-House, the end of shoot or stem forms almost a rectangle, the bent part bowed vertically downwards, the arch insensibly straightening itself as plant grow upwards— But to my surprise when a pan of plants was placed under skylight in the course of 3 days the shoots were all directed upwards.

[Insertion:] (Shoots in Hot-House not all directed to Light)

[in margin:] Perhaps growth somewhat checked from temperature not being high enough. (see below for Temp.)

A plant 1 ft 10 inches 20 inches high had glass filament with 2 triangular triangular lights fixed on convex light a little on convex surface — the tip being forming less than right angle with the main stem. [sketch] vertical glass

The filament was consequently a little inclined upwards toward the vertical glass & the movements of axil were traced during 4 days whilst it straightened itself — tracing on vertical glass— the descending lines show that shoot was rising straightening itself or rising—; whereas an the ascending lines show that cu shoot was descending — or curvature increasing. (Temp. on 10th 18° 1/2 - 19° C. — on 11th 17° 1/2 to 18° — on 12th 17 1/2 to 18 1/2 C.) Shoot stood 9 1/2 inches from vertical glass.— See tracing which shows that on first day the shoot did not rise or straighten itself at all, but on next day or 11th did so for the line descended whole day (with one rise between 10° & 1°) & in zig-zag line, showing that some circumnutation. //at' 4° P.m the tip formed a rectangle with the straight upper part of stem.

During night rose a very little, &, then descended next day till 11° 10' a.m, & then it

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Smithia Pfundii

circumnutated in the most conspicuous manner till 7° 20', it then began again to descend, (ie shoot rose) On the During the night rose considerably, but (ie terminal shoot became bend bent downwards.)— On next day (13th) chiefly descended but with one fine circumnutation between 10° 30' am & about 2° P.m— & then descended & by this time glass-filament stood nearly vertical & tracing cd not be continued on vertical glass— All the tracing after 4° P.m on the 11th much exaggerated for oblique on vertical glass.—

On another plant, with terminal shoot at right angle to stem, a filament with light was fixed transversely on the convex summit & traced during 10th, 11th, 12th.— The movement to right in Tracing shows the ascent or straightening of the shoot, & we clearly see that it must have circumnutated up & down, ie from left to right in Tracing, but this not good plan, for any lateral movement greatly exaggerated.

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Smithia Pfundii

July 26th The terminal part of shoots ar now form rectangle or rather less than one with lower part & are quite independent & lateral light.— I think the most probable explanation of shoot becoming straight under skylight is that there was growth enough there in cool place for shoot slowly to straighten itself, but not enough for terminal portion to grow out laterally or rectangularly.—