Biosystematic Studies onMaianthemum (Liliaceae-Polygonatae)

V. Variation in Gross Morphology, Karyology, and Ecology of North American Populations ofM. dilatatumsensu lato

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The North American populations ofMaianthemum dilatatum sensu lato (=M. kamtschaticumauct.) were studied from morphological, karyological, and ecological standpoints, and were compared with those from Northeastern Asia. It became apparent that the variability of North American populations ofM. dilatatumis quite broad, but differs significantly in several important morphological characters from that of Northeastern Asiatic populations, and thus forms another additional discrete geographical population group withinM. dilatatum. In comparison with the Asiatic plants, those from North America have much more robust and taller flowering scapes with longer racemes, ranging from 3 to 6 cm in length, and more robust rhizomes. The cauline
leaves are much larger, often markedly thick, lucid, and ovate which are clearly attenuate toward the tip. Ecologically, the habitats of North AmericanM. dilatatum extend primarily in the underlayer of evergreen coniferous forests represented byPicea sitchensis, the underlying ecophysiologic conditions markedly distinct from those in Eastern Asia. Karyologically, however, the North American plants proved to be diploid with
2n=36 chromosomes, with karyotype composition quite identical to those observed in Asiatic materials, namely, 2n=36=4V (2V₁+2V₂)+16J+8j+8v.