RECORD: Darwin, C. R. 1875.10.20-.12.29. Melastomaceous Plant. CUL-DAR205.8.58-59. Edited by John van Wyhe (Darwin Online, http://darwin-online.org.uk/)

REVISION HISTORY: Transcribed by Christine Chua and edited by John van Wyhe 4.2022. 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 volume CUL-DAR205.8 contains notes on the genus Monochaetum and other plants.


[58]

Oct. 20. 1875. Melastomaceous Plant.

[in margin: Pleroma, unnamed Sp. from Brazil, from Kew] upper part of [illeg] protected & thickly clothed with [fica] Bristler.

Tall straggling bush with very large fine purple flowers. – 2 sets of stamen of 5 each quite alike, but then near centre of flower smaller. – Pistil upturned – By passing down & letting fly both sets of stamens, clouds & little jets of white very fine-grained pollen emitted - & this seems necessary for emission by turn is a force, no doubt this all adapted for insects to visit centre of flower – I shd think pollen too little & incoherent for pollen collectors.

[illeg] of various curved out like bushes. – Lower part of ovaria with [illeg] scales, & sometimes little fluid here which seemed to me sweet. (I think some error, all seems quite dry & no soft tissue to penetrate) I cannot conceive what attraction is – possibly secretes under proper climate

58v]

Oct 26 – 75

Crossed 3 fl with pollen from long stamens of other fl on same plant} white Thread

2 fl with pollen from short stamens of other flower on same plant} Black Thread ß

3 fl with pollen from both stamens of other flower} White & Black Thread

Dec 29th 1875

2 pods with black thread

2 black & white

Self-fertile 3 white, (but one of them prematurely set, containing chiefly imperfect seeds, with a few perfect like little snail shells –

(Not one flower on which bush has spontaneously set a capsule)

[59]

Plain watch glass White Thread

numbered watch glass Black Thread

Red glasses Black & white Thread

Blue glasses No thread

The 3 white thread all set, but one contained very few seeds – the other 2 more fine seed than any of the others except those with black & white thread which contained an almost equal quantity. – Of black & white 2 set. –

Both black threads set, but contained a very large proportion of small & shrivelled seed which [mournfully] wd not set.

It is clear that pollen from longer stamens more effective.

Two flowers on white plant (in winter when no insect in House) set spontaneously in one of them contained a very few seed, & the other but mingled with innumerable shrivelled seeds.


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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 25 September, 2022