Darwin Correspondence Project

Down, | Beckenham, Kent.

Sat.

My dear Mr Farrer

I send the following extract from a letter recd yesterday from F. Müller in S. Brazil, as a caution about Passiflora in contrast with Tacsonia.

Do not trouble yourself to acknowledge this

Yours very sincerely | Ch Darwin

``In one of your letters you called my attention on perennial Passiflora. I have in consequence planted several species into my garden; only 2 have as yet flowered, & these are self-sterile. In one species the first flowers, which appeared after transplantion, had contabescent anthers.

As to the fertilization of Passiflora, Delpino thinks in his interesting ``Ulteriori osservazioni sulla Dicogamia'', which I recd a few days ago) that in the larger species this is effected by humming birds. I had come to the same conclusion by observing how frequently these flowers are visited by humming-birds, while I did not yet see neither humble-bees, nor butterflies, nor any other large insects able to fertilize them.''