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

Abstract

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, 1–1.5 mm 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, 0.5 mm wide, while E. manipuliflora has mostly ellipsoid seeds 0.7 mm 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.

Keywords:

• Erica
• Ericaceae
• Gypsocallis
• seed coat
• seed morphology
• taxonomy

Acknowledgments

We would like to thank every person and institution that has provided seeds for this study (see Appendix) and curators from the herbaria visited. Two anonymous reviewers made very useful suggestions. This research was partially supported by the project: CGL2006-06890, Ministerio de Educación y Ciencia, Spain.