Intraspecific polymorphism of pollen sculpture inParis tetraphylla A. Gray (Liliaceae)

Paris tetraphylla has a greater diversity of pollen exine sculpture than was previously thought. On the basis of 357 plants from 52 localities of Japan, we distinguished seven sculpture types that are tentatively referred to here as G₁, G₂, G₃, R₁, R₂, R₃ and S. G₁, G₂ and G₃ have gemmate sculpture in which the gemmae are characteristically large, medium and small in size, respectively; likewise, R₁, R₂ and R₃, have coarsely to finely ruglate sculpture; and S, scrobiculate sculpture. In general, any one of the seven types always or predominantly occurs in each plant, thus allowing us to make comparisons among plants and further among local populations. We thus found that G₂ and G₃, respectively, are the most and the second most widespread and occur in plants of 41 and 22 respectively, of the localities examined, although their frequencies differ with locality. Generally R₃ occurs in plants distributed at higher latitudes, while R₂ is rather widespread and common to plants growing on high mountains. G₁ and R₁ are restricted to plants occurring south of Ibaraki Pref. and north of Gunma Pref., respectively. Such localized distributional patterns of some types may reflect the reproductive nature and the history of geographical isolation inParis tetraphylla over the Japanese Islands.