The Complete Work of Charles Darwin Online

RECORD: Darwin, C. R. 1881.07.08-25. Acacia lophantha. CUL-DAR67.71. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 3.2023. 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-DAR67 contains notes on 'bloom'. Francis Darwin explained: "His researches into the meaning of the 'bloom,' or waxy coating found on many leaves, was one of those inquiries which remained unfinished at the time of his death. He amassed a quantity of notes on the subject". LL3: 339. See an Introduction to these folders by Christine Chua & John van Wyhe.

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July 8th. 1881. Acacia lophantha — gathered leaf — leaflets protected on both sides by bloom — rubbed with needle pulvini of the 3 pairs of terminal leaflets & by slowly they rose from near horizontal position to that opposite leaflets, formed less than rectangle with one another & pointed more towards apex of leaf — like sleep position. — At night leaflets went partially to sleep & woke in morning (9th) — The pulvini of 3 pairs of terminal leaflets again rubbed & again they rose or moved as before.

July 25th. syringed 6 pairs of terminal leaflets with water at 90°-96° for 4'

These leaflets were almost horizontal; but after a few minutes they rose & twisted forwards towards apex of leaf, so that their blades stood almost

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vertically & well adapted for shooting off w rain. — After above one hour when looked at again these leaflets had become horizontal.

It was a young, but fully-formed leaf the second from unfolded apical leaf on Branch. —

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