Comparative seed morphology in related high-mountain species of the genus Aquilegia (Ranunculaceae)

Although the relevance of seed morphology in systematics is widely recognized, its contribution in the seed plant classifications is often neglected. In this study, we performed a comparative morphometric analysis of the internal and external morphology of seeds in closely related species of the genus Aquilegia. Seed length, width, thickness, sphericity, mass, embryo to endosperm ratio at dispersal and micro-or-namentation of the integument are examined in five high-mountain species of the northern Apennines and the western Alps. Multivariate ordination aggregates the species in two morphological groups: the first one brings together the populations of Aquilegia lucensis and A. alpina, characterized by larger, heavier, and more spherical seeds; the second group includes A. bertolonii, A. ophiolithica and A. reuteri, ex-hibiting smaller, lighter, and ellipsoidal seeds. Altogether, our results do not support a clear separation of all the taxa based on seed mor-phology, nevertheless, each of the investigated species shows a specific combination of seed character states.