RECORD: Darwin, C. R. & Francis Darwin. [1874?].09.09-10.04. Dionaea. CUL-DAR59.1.22-24. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 10.2022. 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 volumes CUL-DAR 54-61 contain material for Darwin's book Insectivorous plants (1875).

Dionaea muscipula is the Venus flytrap. These notes are for Darwin, C. R. 1875. Insectivorous plants. London: John Murray. (F1217)


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Sept 9th 8° 40' Dionaea

flat bit of dry neat & dry albumen on 2 leaves.

Sep 10 [illeg] 7 AM.

The bit of meat though so dry as to be brittle when put on, became very slightly damp during the night owing to the plant having been covered with a bell-glass, & consequently some bits had caused some acid secretion

(A bit of dried albumen continued still dry & had caused not a trace of secretion

Soaked the bit of albumen & placed it on blotting paper & replaced it in the leaf. also put on a bit of dry gelatine

Sept 10th At 4° 30; the albumen had caused much secretion, barely acid.

Sept. 11th 7° 30 A. m. To my great surprise the bit of albumen had caused the end of leaf on which it stood to partially close & when I ↘

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removed albumen but not the albuminous secretion leaf slowly closed. This very important — (albumen of good size) as bearing on slow closure of leaf round captured insect did not occur before. — (I marked this leaf with white Thread—to see when opens.)

it is curious that how little absorption must suffice viz meat slightly dampfrom bit being left on leaf under dry Bell-glass.

Sept 13th 8° Am the distal end began to open & now Sep 14' is much more open than the other end, where I believe the albumen had lain.

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Dionaea 1874

Sept 10' 7° 30' put bit of dry gelatine on leaf no effect after 24° — soaked it & put it Sept 11th at basal end of leaf 7° 45' Sept 11.) I plant under damp bell-glass —

I also placed at 5° P.m. Sept 10th last night on leaf on open plant (ie, not under Bell-Glass) a bit of dry meat, & this morning Sept 11th after 15° no secretion. —

I damped it & placed it Sept 11th (7° 45') at distal end of leaf under damp-Bell-glass

Sept 12th 7° A.m. The damp gelatine has caused no secretion & no closing of leaf.— Whereas the damped meat has caused secretion, judging by narrow strip of Litmus paper & has caused thus one end of leaf almost to shut & it shut suddenly whilst inserting Litmus paper. We thus have that damp food causes secretion & an immeasurably slow movement, ie. if piece large enough.— Perhaps formerly I had not watch ↘

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Evidence very good in both cases, as leaf closed at one end alone very slowly —

(Oct 4th examined the roots of a moderately good plant still growing & there were only 2 single roots about 1 inch in length, proceedingfrom small bulb-like enlargement at the bases of the leaves,

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the insects &c &c long enough so that I did not discover these slow movement. Observe opening of leaf as it will show difference of gelatinefrom albumen & meat

Meat & gelatine of about same size.

Sept. 23d at 7° A.m. Leaf closed at 12° the end with gelatine quite open — the end with meat still half-closed — so no great difference in period of opening — much softened gelatine left. —

Oct 4th Put leaf in water 59° did not close, though kept in for about a 1', but when slowly withdrawn still attached to plant shut rather quickly. (After rain, though doubt on sugar & water)

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Sept 23d 8° Am Dipped leaf into water at 65° did not close — cut it off 1/3from top of petiole, dipped it, did not close— yet when I touched filament closed, put it to stand in water.

Sept 24th standing with stalk in water partly opened—

Sept 25th 7° 40' more open submerged it in water at 62° 1/2 did not close; touched filament & it closed — then completely submerged it, by head & footstalk

A second poor leaf, dipped it whilst attached to plant, did not close— touched it filament & it closed. —

After immersed in water or a mere touch; for the in these latter cases the lobes generally began to reexpand in under a day. On the other hand of


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Citation: John van Wyhe, ed. 2002-. The Complete Work of Charles Darwin Online. (http://darwin-online.org.uk/)

File last updated 1 November, 2022