[107]

Canary Grass

Nov. 13th gummed gummed filament to very young blade, next day after shooting up, but all the plants bent during whole day so extraordinary towards me, though kept in darkness, that observations spoiled. I cannot understand this. Did the light of candle with which I looked at them the cause? Or did light to which they were exposed for about 1/4 of Hour whilst filament was gummed on act during whole day? Or had they received tendency previous day in hot-House to bend in one direction? & did this chance to be the direction in which they stood in darkness; this very improbable. —Although all the many plants moved in one direction towards me, for they were upright when experiment begun, yet this one zig-zagged once twice or thrice considerably, so that I suppose nutates.

Nov. 14th I tried again—Filament slipped down on one so useless— On another I tied glass-filament this killed top of plant— On the 3d & old plant on which filament had been gummed transversely previous day I suspect from shrunken appearance of tip that it was injured. There was some zig zagging but whether nutation I dare not say.—

Heliotropism. The plant from previous days' action all pointed obliquely to my left Hand, & at night most continued to do so, but several (a)

[107v]

(Canary grass.)

(a) pointed directly towards me, ie towards the candle taper which I used for observation; they were looked at 18 times in the course of day & this sufficed to make some alter their direction; & therefore I do not doubt that it was the action of taper which caused the day before all to bend towards me —

At 10° 25' P.m Nov. 14th I turned pot round so that all the plants were bowed from me & then put a mortar before them & next morning Nov. 15th (mortar burnt to between 6& 7° a.m) all 29 in number had reversed their curvature & pointed towards where mortar stood. Their upper parts were chiefly bent, as if the white tip was far more sensitive than other parts. The one with glass filament gummed transversely just beneath tip did not bend. It is remarkable compared with other plants that during night of 13th the flexure towards candle was not counteracted by an geotropism.

Nov. 14th 8° 45' P.m Most of the plants are now upright, so that apo an-geotropism has come into play.

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(N.B All my observations on other plants in some degree falsified but the complex courses show that not much falsified.)