Seed morphology and systematics of the European species of Erica L. sect. Gypsocallis Salisb. (Ericaceae)

The European heathers Erica manipuliflora, Erica multiflora and Erica vagans (sect. Gypsocallis) are related species characterized by a glabrous ovary, exerted, muticous anthers and a pale pink, urceolate corolla. The existence of three species is the most accepted treatment for this group, but there are uncertainties about this taxonomic interpretation. In this article, we used seed morphological characters to assess the systematics of the group. Seeds were studied by means of scanning electron microscopy techniques. E. multiflora has a distinct seed type, 1-1.5mm long, flattened, yellowish with a striate-reticulate primary sculpture. E. vagans and E. manipuliflora have smaller seeds, brown with a reticulate pattern. Seeds of E. vagans are globose, 0.5mm wide, while E. manipuliflora has mostly ellipsoid seeds 0.7mm long. However, seeds of E. manipuliflora from the Adriatic coasts are closer to those of E. vagans, and this may support the existence of E. manipuliflora subsp. anthura.