Of the experiments of previous years, those dealing with Matthiola annua and glabra, Zea, and Mirabilis were concluded last year. Their hybrids behave exactly like those of Pisum. Darwin's statements concerning hybrids of the genera mentioned in The variation of animals and plants under domestication, based on reports of others, need to be corrected in many respects.
Letter VIII, July 3rd, 1870. - Letters to Carl Nägeli