Floral biometrics of the Anchusa undulata L. group (Boraginaceae) from the central-eastern Mediterranean

Abstract

A biometric study of floral morphology in the taxonomically critical Anchusa undulata group from the central-eastern Mediterranean highlights a broad range of individual variation. Anther position is the only character separating A. undulata from A. hybrida, but statistical methods suggest clinal variation connecting the two taxa. A. undulata is also present in continental Greece and intermediate plants occur in Italy, Greece and Israel. This indicates that the two taxa are conspecific and suggests subspecific rank for A. hybrida. Subsp. undulata does not belong to the Italian flora, as samples from Sardinia formerly referred to this taxon belong to a group of psammophytic taxa endemic to northern Sardinia and Corsica. In subsp. hybrida, the distribution frequency of the ratio of style length to anther height shows the occurrence of short- and long-styled forms, but in neither case is there reciprocal correspondence in the level of anthers and stigmas. In contrast, A. capellii is characterized by some peculiar features with a narrow range of variation, that warrant specific rank for this little-known Sardinian endemic. Specimens from Cyrenaica differ in quantitative and qualitative characters, but a decision on their taxonomic status requires further investigation. Keys and descriptions are provided and lectotypes of A. hybrida and A. capellii are designated.