Altitudinal Variation of Leaf Venation in Four Species of Geum in the Austrian Alps1)1)Contribution No. 3334 from the Institute of Low Temperature Science, Hokkaido University, Sapporo 060 Japan.

摘要: Summary This paper is concerned with evolutionary trends of plant adaptation to life at higher altitudes. We investigated a morphological leaf character that rather insensitive short term climatic perturbations, and hence reflects genotypic than phenotypic adjustments: The number second-order veins per (NV). Determinations were made in 47 populations 4 species Geum (Rosaceae) ranging from 500 almost 3,000 m altitude the central Alps. Basal rosette leaves on flowering stalks treated separately. following results obtained: 1. Leaf venation shows stepwise, not continuous change associated altitudinal displacement species. 2. Within certain NV tends decrease slightly increasing altitude, whereas intraspecific variation negligible. 3. Species high show much greater leaves, low but reduced elevation Thus, dimorphism respect base top increases altitude. 4. From 2 3 it results, population level are absent or opposite interspecific trend, suggesting changes precursors trends. conclude adaptations altitudes operate level. Venation seems exhibit little leeway acclimation ecotypic differentiation morphotypic barriers seem be very significant evolution alpine plants.