Galphimia is a genus of approximately 26 species of large herbs, shrubs, and treelets belonging to the family Malpighiaceae, which encompasses around 75 genera of flowering plants in the order Malpighiales. The genus name is an anagram of Malpighia, the family's type genus, reflecting this close relationship.
The center of diversity for Galphimia is Mexico, where 22 of the 26 known species are found. One species, G. angustifolia, extends northward into Texas, and G. speciosa reaches as far south as Nicaragua. The remaining four species — G. amambayensis, G. australis, G. brasiliensis, and G. platyphylla — occur in South America, south of the Amazon Basin.
Plants in this genus typically bear yellow flowers and range in growth form from sprawling herbs to small treelets. Eight species from Mexico and Central America are particularly distinctive: their petals become stiff and papery at maturity, persisting well past fruit development. Galphimia gracilis is the most widely cultivated member of the genus, grown as an ornamental in warm regions around the world for its prolific golden-yellow flowers, though it is frequently misidentified as G. glauca or G. brasiliensis.
Galphimia is occasionally confused with Thryallis, another Malpighiaceae genus native to Brazil and adjacent Paraguay and Bolivia. The two genera were once treated together, but Thryallis is now a conserved name under the International Code of Botanical Nomenclature. They are distinguished by the stellate hairs and scales on Thryallis vegetative parts and by the broader-than-long petals of Thryallis, neither of which occur in Galphimia.
Etymology
The genus name Galphimia is an anagram of Malpighia, the type genus of the family Malpighiaceae. This naming convention signals its close relationship to the family's namesake group.
Distribution
Galphimia is centered in Mexico, where 22 of its approximately 26 species are endemic or native. One species (G. angustifolia) extends into southern Texas, and one (G. speciosa) reaches Nicaragua. Four species occur in South America south of the Amazon Basin. Galphimia gracilis has been widely introduced as an ornamental in warm-temperate and tropical regions worldwide.
Taxonomy Notes
Galphimia has historically been confused with Thryallis, a related genus in Malpighiaceae occurring in Brazil, Paraguay, and Bolivia. Some species now placed in Galphimia were formerly assigned to Thryallis; however, Thryallis is now a conserved name under the International Code of Botanical Nomenclature and is maintained as a distinct genus. The two are separated by the presence of stellate hairs and scales on Thryallis vegetative parts, and by the distinctly wider-than-long petals of Thryallis, characters absent in Galphimia.
