The Cytological Aspects of the Deter- Mination of Sex in the Dicecious Forms
نویسندگان
چکیده
IN examining various groups of plants, in the hope of finding one which would throw fresh light on the question of sex determination, the dioecious forms of Lychnis suggested themselves as being particularly suitable. The genus Lychnis, as a whole, is hermaphrodite, and even the dioecious species may readily exhibit this character. In the female flower rudiments of stamens are always present and physiological disturbances may cause them to develop further. In the hybrid between the two nearly related forms L. dioica, L. em. Mill (Afe/andrium rubnim,\ Garcke), and L. alba, Mill. (M. alburn,^ Garcke), these stamen initials tend to develop much further than in the normal pure species, and to reach a fair size, although they do npt usually develop pollen. A more marked disturbance, produced by the attack of Ustilago violacea, Fuck., causes the stamens of female flowers to develop completely, but the anthers usually contain only the spores of the smut. However, Doncaster has reported that he once found, on a diseased plant, uninfected flowers in which the stamens were developed but apparently infertile, although usually such flowers are normal females. Infected male plants remain male in character. Shull worked with a strain of L. dioica\ which did not correspond to either of the two species recognised in
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