[55]

Cassias cotyledons

Nov. 13' C. glauca. Lett. [Lettington] says cots. absolutely closed at 6° P.m & about at 4 ° 10' they were certainly closing & at 6° a.m.

Nov. 14th quite closed, whereas at 7° 30' partly open & by 11° & probably earlier quite open. Cots. with no bloom on upper or lower surface & water adheres to them, Make True leaves repel water & have bloom, I tried on 13th & cd perceive no movement when touched, but on 14th 11°, a cot. which appears horizontal in 10' after being rubbed with little twig for 2' stood at ∠ 124, so apparently had risen 34°.— Another rose 6°— another did not seem to rise at all — Stems most sensitive to rubbing.)

At 12° 30' I tried 2 fresh Cots. I rubbed one on upper surface for 1' 30" with end of twigs & it rose from 107° to 124 ie 17° [diagram]

The other was lightly pinched between my fingers & rubbed on upper surface for 1' & rose from 114° to 127°. ie 13°— These Cots. are not so sensitive as those of S. Brazilian species.— (Used)

(Nov. 14th most of plants well asleep & perfectly at 4° 45'— Pinned open 2 on cork black wool & exposed on lawn clear clear night to temp of 42°, probably fell lower during night, (Radiation) but in morning rain at temp of 50', also bent one over so that lower surface exposed to temp. radiation, horizontally, marked white wool. Next morning 8° 30' at 9° all plants fast asleep or closed, so that paralysed; those The 2 which had been pinned open, partially closed as soon as free, & one quite closed & then responded, & then shut again, so quite alive.

(over)

[in margin:] (Nov. 23d Drops of water placed gently on Cots. no effect.)

(Nov. 27' drops of tepid water for 1' produced no effect)

[55v]

(Not worth using)

at 11° (15th Nov.)' beginning to open. — At 6° P.m. 1/2 asleep

(Nov. 20' I put out same seedlings again, fastened in same manner. Clear night, Temp. 36°, but in the morning there was hoar first frost in many places. The pot stood within a very large pot so as to break the wind which was strong in the early part of the night. Nov. 22d I can see no signs of injury to Cots, or little growing axis. This hardiness is astonishing in an Indian plant, as stated by Steudel—)

Nov. 25th there are some brown speckles on the upper surfaces of both leaves, & it is very odd so there are & still more plain on upper surface of the one upper cot. of the plant (white wool) which was bent over to one side; whilst there is no sign of injury on the lower surface itself which was exposed!

Radiation & Bloom on Cots

[56]

Cassia Cotyledons

C. pubescens. Nov. 13th Lett says quite open partly closed at 6° P.M. quite open at 6° a.m.

Nov. 14th. — no bloom on surface.— Used

Yesterday & today cd detect no movement from rubbing surface.

Nov. 14' Both quite closed at 4° 45' (pinned one open see (Black wool) see paper on C. glauca. The one to which nothing had been done was quite asleep at 9°, but expanded at 11° — On following night both plants thoroughly asleep.—

(Not used)

Radiation

(Nov. 21', I think the growing axis between the cots. of the seedling which was pinned open have been killed & dropped off & the Cots. have ceased to grow grow; important, if confirmed, as showing that the Cots. act as protecting the tender little leaves & growing point.— Nov. 26. The Cots. have never increased in size & plant dying, whilst the other plant which was closed at night is perfectly sound). (Nov. 27. not affected by dripping of tepid water for 1')