The taxonomy of Galium crespianum J.J. Rodr. (Rubiaceae), a Balearic Islands endemic revisited

Abstract

Galium crespianum J.J. Rodr. is a perennial plant inhabiting cliffs and crevices on the Balearic Islands. Although it was described from the mountains of Mallorca, several populations from the islands of Eivissa and Formentera have been traditionally considered as belonging to the same species. A careful comparison of specimens from the western and eastern Balearics revealed several discriminant features in gross morphology (robustness and habit of the stems, presence or absence of hairs at the internodes and leaves, waxiness of stems and leaves, shape of the inflorescence, flower colour and scent) and stem anatomy. In addition, several mutations in the ribosomal ITS sequences distinguished western and eastern plants. It is proposed that the plants from Eivissa and Formentera previously subsumed under G. crespianum be recognized at the specific level as G. friedrichii N. Torres, L. Saez, Mus & Rossello nom. nov. The new species is tetraploid (2n = 44) and shares morphological features with G. crespianum or with several taxa in the G. glaucum complex from the south east Iberian peninsula, to which it is most probably related.