Natural hybridization in JapaneseCalamagrostis |
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Authors: | Tuguo Tateoka |
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Institution: | (1) Department of Botany, National Science Museum, Shinjuku, 160 Tokyo;(2) Present address: Department of Botany, Natural Science Museum, 300-31 Ibaragi |
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Abstract: | Morphological and pollen studies were made for the collections belonging toCalamagrostis langsdorffii, C. Sachalinensis, C. longiseta, C. nana and various intermediates between these species from central Honshu, the chromosome numbers of which were reported in a previous
paper (Tateoka, 1976). Additional collections made from the Akaishi Range in 1976 were also subjected to the present work.
The intermediates showed 0%, or nearly 0%, pollen stainability and a mosaic of morphological features of putative parental
taxa which can be estimated to occur for F1 hybrids. This estimation was sustained by a comparison with the pattern of character expressions for the artificially raised
F1 hybrids of various European species ofCalamagrostis as reported by Nygren (1962). These results as well as field observations strongly suggested that the intermediates may be
wholly or almost wholly F1 hybrids. The hybrids were sometimes found in abundance within a limited area, but seemed to have little capacity to migrate
from the places where they originated. The following combinations, which were not previously recorded, were disclosed:C. longiseta×C. sachalinensis, C. langsdorffii×C. nana, C. langsdorffii×C. longiseta, C. longiseta×C. nana. Possibilities of introgression in these hybridizing species were discussed. The hybrids were tetraploids except one hexaploid
which was discovered in a mixed population ofC. nana, C. longiseta and their putative F1 hybrids at the tetraploid level. The hexaploid in question, which seemed to have resulted from the participation of an unreduced
gamete, was very similar morphologically toC. nana subsp.hayachinensis distributed in the mountain far distant from central Honshu. Geographical distributions of the hybrid plants were surveyed
through examination of the herbarium specimens. |
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