Rarity and Endemism in Coutaportla Urb.: An Updated Taxonomic Perspective (Chiococceae, Rubiaceae)

Coutaportla Urb. originated from Northern Mexico and spread to parts of Guatemala and Honduras, bearing tetramerous or pentamerous flowers and capsules that dehisce loculicidally. The delimitation of the genus has been controversial since Lorencea was segregated; however, both molecular and morphological evidence reject this separation, supporting the recognition of five species within Coutaportla. This study provides an updated taxonomic treatment that incorporates newly described species, identification keys, distribution maps, and detailed descriptions. A thorough review of the taxonomic literature and protologues was conducted, complemented by the examination of herbarium specimens (including types) and consultation of online collections to refine species descriptions and distribution data. The genus comprises five species, four endemic to Mexico and one extending into Central America. Three of these are known only from their type localities. Species occur in a variety of environments, ranging from arid and temperate to tropical and humid zones. Diagnostic features include ovary placentation (subapical, median, and basal), along with floral and foliar characters. Morphological evidence supports synonymising Lorencea with Coutaportla. The genus is highlighted as a subendemic Mexican element, with most species having restricted ranges and requiring conservation attention.