Morphological variability of the two altitude vicariants, Anthoxanthum odoratum L. s.s. and Anthoxanthum alpinum in the Babia Góra Massif (Western Carpathian Mountains – Żywiec Beskid, Poland)

Abstract

Anthoxanthum odoratum, a species occurring below the upper forest limit on the Babia Góra Mountain, is replaced by Anthoxanthum alpinum in the subalpine and alpine belts. It is a typical example of altitudinal vicariance. The aim of the study was to determine the range of morphological variability within the populations of A. odoratum and A. alpinum along an altitudinal transect. Special attention was paid to specimens growing in the transition zone between both species. Plant material was collected from 11 localities and samples were examined with respect to 24 morphological traits of the panicle. Results were analysed with the use of multidimensional statistical methods. It was found that A. alpinum grows above the upper forest limit. Populations of this species have a relatively small range of variability of the studied traits. Samples originating from the contact zone, situated at the altitude of c. 1166 m above sea level, consist of individuals representing both species. In turn, samples collected below the upper forest limit represent A. odoratum and occasionally A. alpinum, and reveal considerable morphological differentiation.