[55]

Gardeners Ch, 1862. p. 648

Heterocentron roseum not in systematic working

H. mexicanum has white flowers

H. Macrostachyum has pink, but otherwise very like H. mexicanum¹

¹ Darwin had been examining the two sets of different stamens in the flowers of Heterocentron roseum since October 1861. Hooker sent examples from Kew. Darwin thought the family of Melastomataceae might possess a unique form of dimorphism. After pollination experiments on several species of this family of flowering plants through 1863, he was unable to explain the two sets of stamens. Heterocentron roseum and Heterocentron macrostachyum were never mentioned in Darwin's publications. Heterocentron mexicanum was reported in Cross and self fertilisation, in a "List of Plants which, when Insects are excluded, are either quite sterile, or produce, as far as I could judge, less than half the number of Seeds produced by unprotected Plants." "Heterocentron mexicanum (Malastomaceae).—Quite sterile; but this species and the following members of the group produce plenty of seed when artificially self-fertilised." (p. 364). See the numerous letters on these plants in Correspondence vols. 9-10 and Darwin's notes in CUL-DAR205.8.