RECORD: Darwin, C. R. & Francis Darwin. 1878.07.05-08.06. Porliera Hygrometrica / Draft of Forms of flowers, folio 244. CUL-DAR209.14.105-108. Edited by John van Wyhe (Darwin Online,

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 7.2023. RN1

NOTE: See record in the Darwin Online manuscript catalogue, enter its Identifier here. Reproduced with permission of the Syndics of Cambridge University Library and William Huxley Darwin. The volume CUL-DAR209.14 contains material for Darwin's book Movement in plants (1880).


July 1878

Porliera hygrometrica (Sapindaceæ)

(Circumnutation & Sleep of leaf.)

A fine large vigorous bush 3-4 4-5 ft high.— A leaf, on an upright twig, 3/4 of inch in length — with [sketch] filament fixed fixed longitudinally to midrib traced on vertical glass under skylight

Apex of leaf 7 1/2 inches from glass. Temp. on 7th 19 1/2 to 20 1/2 C. on 8th 19° 1/2. — Stem secured to stick at base of leaf.—

See tracing: on 2d night filament in rising during night got caught under adjoining leaf so position on morning of 9th cd not be given.— See tracing — falls in evening & rises during very early morning to former position. On first day between 1° & 4° stood almost still circumnutating slightly about same point— on 2d day after falling till betw& 5° then rose till 4° & then the nocturnal fall began — so clearly has one circumnutation in early afternoon.—

I cannot make out whether whole leaf or leaflet sink.


Porliera Hygrometrica

July 5th

Fine bush 5? ft high covered with leaves arrived from Kew soil moderately damp — watered slightly on morning of July 6th Hot & dry weather & now watered again slightly — not watered again or syringed— On July 27 & 28 leaves drooped, but [illeg] leaflets were not asleep. On 29th when shaken a good some leaves fell off— Plant looked dying, at night was unable to sleep.

(dry rigidity) so watered & syringed it moderately: on morning of 30th looked as fresh as ever. — (I suspect agitation & drought necessary to make leaves sleep?) & on night of 30th leaflets went to sleep as well as ever.

A twig cut off withered very slowly in my study. A branch in connection with bush enclosed on July 16th in bottle with quick lime seemed fresher (29th) than other twigs!!

29  16 / 6

July 31' shook branch for 2', greatly whipping against my hand I believe leaves become depressed, but leaflets did not close in the least

Aug 2d exposed during day high— N. wind from 12° 15' to 3° P.m leaflets did not go to sleep— — nor did shaking branch for 2' yesterday.—

Aug 6' soil now looks very dry— exposed plants from 7° 30' a.m to 4°. 30' P.m out-of doors light wind but damp air — leaflets did not go to sleep.

I ought to allude to as another one of Sleep of Plants

Failure — Consult describer of species— why called Hygrometrica. — Habitat

Specimen & Habitat of Wurzburg species

(Sleep of Plants)


From Kew

Porliera hygrometrica (Sapindaceæ)

July 6 1878— Leaves pinnated like Mimosa— on upright leaves Branches each sinks at night so as to hang down, almost vertically & parallel to stem — on Horizontal branches no such depression occurs—. The leaflet move forward, so that their midribs become parallel to main petiole (just as with some Leguminosæ) & thus the leaflets overlap each other; but then upper surface on opposite sides of petioles do not come into quite close contacts, owing to intervening main petiole; but upper surfaces are in contact with lower surface of next leaflets forward— about 1/2 of lower surface [sketch] of each leaflet exposed to air—

Leaflet no trace of bloom, wetted with remarkable ease on both surfaces.—


Porliera hygrometrica:— filament fixed to longitudinally [2 words illeg] of the main petiole of leaf; movements traced under a skylight on a vertical glass, from 9. 35 a.m during 36 40 hours, under skylight. July [illeg] 7th to middle of night of the 8th, when the filament caught on adjoining branch. — Apex of leaf 7 1/2 inches from vertical glass.) Temp. 19 1/2 - 20 1/2° C



Ch VI Concluding Remarks

= siderable length, before the grains have touched the stigma; but botanists believe that they afterwards draw nourishment from the conducting tissue of the pistil. It is hardly possible to doubt this must

[The text of the draft corresponds to Forms of flowers, p. 251.]

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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (

File last updated 18 August, 2023