Dear Darwin,

On second thoughts an-heliotropic will not do at all. It would mean non-heliotropic. I should have thought that the best nomenclature would be

But I think that it would be quite possible to speak of heliotropic and aphheliotropic. I presume that the latter word would in general lose its second h, and be written apheliotropic.¹ I do not know whether from a philological point of view these words are correctly formed.

I should have thought that negative heliotropic was an unhappy phrase.

Yours ever, | Henry Jackson.

F. Darwin Esq.