Helichrysum nicolai (Compositae, Gnaphalieae), Systematics of a New Dwarf Local Endemic of the Cape Verde Islands, W Africa

Helichrysum nicolai from the Cape Verdean island of São Nicolau is described as a species new to science and illustrated. The systematic position in Helichrysum of this acaulescent dwarf rosette shrub with heterogamous capitula, in which the female flowers outnumber the hermaphrodite ones, is established using an ITS phylogeny based on maximum parsimony and Bayesian inference analyses. The new species is most closely related to the Canary Island endemics H. alucense and H. monogynum. The closest relative to these three species are not the other members of the genus on the mid-Atlantic archipelagos but H. somalense from the Horn of Africa region and the southern Arabian Peninsula and the widespread tropical African-S Arabian-SE Iranian H. glumaceum, to which the SE Iranian H. makranicum is found to be conspecific. The phytogeographical significance of these relationships is discussed and at least three independent colonization events of the mid-Atlantic archipelagos by Helichrysum are concluded from the molecular data available.