J. Hered. 40(1): 3–6 (1949).
II. The Separation of Homologous Chromosomes in Trillium Species
Department of Botany, University of Wisconsin

TREATMENT with solutions of sodium nucleate of tissues under. going mitosis induces, amongst other departures from normal, a certain number of reduction type divisions as reported by Huskins.2,8 Reduction-divisions have also been found in Allium root tips alter treatment with phosphates (Galinsky, unpub.) as well as in untreated roots from onions which have been stored for several months and in untreated Trillium root tips near the end of their root formation period.

The theoretical and practical implications of these reduction-divisions, both natural and induced have been discussed in detail by Huskins4 in the first paper of this series. The initial work on Allium cepa left unanswered the question of whether or not homologous chromosomes are preferentially separated in these segregations, owing to the fact that it is difficult to distinguish homologues with any degree of certainty in that species. This is the primary question to be considered in the present paper.

The most common observation, from all sodium nucleate treatments in all eleven plant genera so far studied in this program is the separation of the chromosomes into two groups. This separation may occur at any degree or stage of chromosome condensation from that characteristic of early mitotic prophase to that of mitotic or even meiotic metaphase. With regard to these separations two specific questions may be asked: 1) do the two groups tend to equality and 2) are homologues separated with greater than random frequency The Allium data presented by Huskins4 gave a positive answer to the first question and it is confirmed by the Trillium data presented below. They give, in addition, a positive answer to the second question.

Somatic Segregation Biblio