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Natural interspecific hybridization between sexual and apogamous species of the beech fern genus Phegopteris Fée

1972; Canadian Science Publishing; Volume: 50; Issue: 6 Linguagem: Inglês

10.1139/b72-158

1480-3305

Gerald A. Mulligan, Lionel Cinq-Mars, William J. Cody,

Ecology and Vegetation Dynamics Studies

A clone of beech fern found growing on a mountain near Rougemont in Rouville County of Quebec is shown to be a natural hybrid between two species of Phegopteris that grow together at that location, the circumboreal species P. polypodioides Fée and a species endemic to eastern North America, P. hexagonoptera (Michx.) Fée. Phegopteris polypodioides is shown to be an apogamous triploid (2n = 90), P. hexagonoptera a sexual diploid (2n = 60), and the interspecific hybrid between these two species an apogamous tetraploid (2n = 120). It was concluded that the natural hybrid was produced by the union of a motile gamete, containing 90 chromosomes, from an antheridium on a prothallus of apogamous P. polypodioides with a female gamete, containing 30 chromosomes, on a prothallus of sexual P. hexagonoptera. This is the second report of interspecific hybridization between sexual and apogamous species of ferns. The morphology of both parents and the hybrid supports the conclusion that the apogamous species contributed more genetic material to the hybrid than did the sexual species. It is suggested that this hybrid probably occurs at other locations where the ranges of P. polypodioides and P. hexagonoptera overlap.