VII-The cytology of trisomic mutations in a wild species of Oenothera

Abstract

In September, 1932, seeds were collected of a wild Oenothera on the peninsula known as Penzance, near Wood’s Hole, Massachusetts, from plants growing by the roadside. The following year a culture of fifty plants was grown in the experimental grounds at Regent’s Park. They were quite uniform in character except two plants to be mentioned later. This species in cultivation has foliage remarkably like that of the Oenothera Lamarckiana of de Vries’ experiments, but with leaves somewhat narrower, more pointed, and less crinkled than in that species. The flowers were, however, small like those of O. biennis . It is proposed to call this species O. paralamarckiana , not only on account of its resemblance to O. Lamarckiana , but also because it produces numerous trisomic mutations, in fact, in a much higher proportion than they have ever appeared in O. Lamarckiana itself. A full technical description of this new species will be published elsewhere. Figs. 1 and 2 are from photographs of typical plants of the 1933 culture in the rosette and flowering stages respectively.