Acourtia macrocephala

Acourtia macrocephala is a perennial herb or robust subshrub in the family Asteraceae, belonging to the New World genus Acourtia. The epithet 'macrocephala' derives from Greek meaning 'large-headed,' referring to the relatively large capitula that distinguish this species within the genus. As a macrocephalous Acourtia, this plant likely produces prominent, showy flower heads with numerous florets, making it more conspicuous than many of its congeners. The genus Acourtia is distributed from the southwestern United States through Mexico and Central America, with Mexico being the primary diversity center. The species with large capitula may be particularly attractive to long-tongued bees, butterflies, and other pollinators that can access the elongated floret tubes of bilabiate or ligulate composite flowers. Like other Acourtia species, this plant has alternate or opposite leaves with toothed margins and glandular or non-glandular hairs. Stems are erect, herbaceous to somewhat woody at the base. Capitula are borne in terminal panicles or corymbs, with several series of involucre bracts. Achenes are slender and ribbed with a pappus of capillary bristles. Acourtia macrocephala likely inhabits rocky slopes, canyon walls, montane scrub, and dry forest margins in the Mexican highlands. The genus plays an ecological role as a nectar source in xeric and semi-arid ecosystems. Taxonomically, Acourtia has been subject to several revisions separating it from Perezia and related genera based on molecular phylogenetic analyses.