Most of the species in this genus are heterostyled or dimorphic; that is, they present two forms,--one long-styled with short stamens, and the other short-styled with long stamens. (6/6. See my paper ‘On the Two Forms or Dimorphic Condition in the Species of Primula’ in ‘Journal of the Proceedings of the Linnean Society’ volume 6 1862 page 77. A second paper, to which I presently refer ‘On the Hybrid-like Nature of the Offspring from the Illegitimate Unions of Dimorphic and Trimorphic Plants’ was published in volume 10 1867 page 393 of the same journal.) For complete fertilisation it is necessary that pollen from the one form should be applied to the stigma of the other form; and this is effected under nature by insects. Such unions, and the seedlings raised from them, I have called legitimate. If one form is fertilised with pollen from the same form, the full complement of seed is not produced; and in the case of some heterostyled genera no seed at all is produced. Such unions, and the seedlings raised from them, I have called illegitimate. These seedlings are often dwarfed and more or less sterile, like hybrids. I possessed some long-styled plants of Primula veris, which during four successive generations had been produced from illegitimate unions between long-styled plants; they were, moreover, in some degree inter-related, and had been subjected all the time to similar conditions in pots in the greenhouse. As long as they were cultivated in this manner, they grew well and were healthy and fertile. Their fertility even increased in the later generations, as if they were becoming habituated to illegitimate fertilisation. Plants of the first illegitimate generation when taken from the greenhouse and planted in moderately good soil out of doors grew well and were healthy; but when those of the two last illegitimate generations were thus treated they became excessively sterile and dwarfed, and remained so during the following year, by which time they ought to have become accustomed to growing out of doors, so that they must have possessed a weak constitution.