Distribution and naturalisation of Heterotheca subaxillaris (Asteraceae) in Morocco

Abstract

Floristic records are essential for refining national plant inventories and filling gaps in global biodiversity databases. During a recent floristic survey of the Maamora Cork Oak Forest in northwestern Morocco, the species Heterotheca subaxillaris (Lam.) Britton & Rusby was found to be widespread, particularly in the western and central regions. This species grows primarily on red sandy clay soils, in both open spaces and beneath the canopy of Quercus suber and Eucalyptus trees. Heterotheca subaxillaris is native to North America and had previously been recorded in Morocco, but no details had been provided regarding its occurrence and distribution. During this study, we confirmed that the Moroccan population represents the type subspecies, Heterotheca subaxillaris subsp. subaxillaris. Field observations suggest that the plant has become naturalised in the region. Plants form locally abundant populations and flower throughout most of the year.