Influenza del substrato sulla variabilità intraspecifica di Thlaspi rotundifolium (L.) Gaudin nelle Alpi Occidentali

Thlaspi rotundifolium s.l. is characterised by a high intraspecific variability which has led during the last two centuries to an unclear frame about its systematics and nomenclature. In the present work the influence of lithic substratum on the morphological variability is examined in plants collected in Piemonte and Valle d’Aosta (W Italian Alps). Morphometric analysis of the stylus length, which is the most significative character used to discriminate the different entities, has been carried out on 62 specimens of Herbarium Pedemontanum of the University of Turin (HP-TO) and on 9 recently collected samples. Data highlighted that the stylus length varies continuously from 1 to 6 mm and is influenced by Ca and Mg contents of the colonised lithotypes (serpentinites, metabasites, dolomites, calcschistes and limestones).