To George Bentham   12 December 1876

My Dear M^r Bentham,

I am very much obliged for your long & interesting letter.¹ Restio seems a wonderful case.² With respect to Boronia pinnata I have examined all the flowers which you have kindly sent me, but though there is some variability in the length of the stamens & pistils I can see no evidence of the existence of two distinct bodies of individuals. Therefore I do not think it would be worth spending your valuable time in searching for other specimens.³ I have been often deceived about heterostyled plants by several causes. Sometimes the pistil increases so much in length after two or three days, that young & old flowers seem heterostyled. Asa Gray thought Amsinckia was heterostyled, but it is only a case of great variability in the parts.⁴ Again A. de Candolle thought Asperula scoparia was heterostyled, but it is diœcious with rather large rudiments of the sexual organs.⁵ This morning I have been examining Ægiphila obdurata (which was named for me at Kew, perhaps by you)⁶ and instead of being heterostyled, like the two species which you sent me, it has become diœcious. I see in Steudel that two species of Ægiphila grow in India & the Phillipines: do you know whether these extra-American species are heterostyled like Æ mollis & elata?⁷ I ask because it is of some importance to discover whether heterostyled species of the same genus are found in distant parts of the world, as rendering it probable as rendering it probable that this structure is of ancient origin. If you know nothing of the extra-American species of Ægiphila, pray do not trouble yourself by sending any answer.

With very many thanks I remain, my dear M^r Bentham | Yours sincerely | Charles Darwin