PlantaeDB Logo
Login Sign-up

Genus Hintonia in Family Rubiaceae

In botanical taxonomy, a genus (plural genera) is a rank used to group closely related species within a family. In the hierarchy, genus sits below family and above species.

Genera are defined by shared morphological, anatomical, and genetic characteristics (for example, features of flowers, fruits, seeds, or leaves) that indicate a close evolutionary relationship among the species they contain.

Each genus can include one or more species. Examples include Rosa (roses) and Solanum (nightshades, including tomato and eggplant).

Do you wish to read more about plant taxonomy? Click here!

Genus Description

Suggest a correction!

Genus Hintonia Bullock (Rubiaceae) comprises approximately seven species of trees and shrubs, primarily distributed across the seasonally dry tropical forests and thorn scrub of southern and western Mexico, with a single species reported from adjacent regions of northern Central America (POWO, 2024; WFO, 2024). The type species is Hintonia latiflora (Sessé & Moc. ex DC.) Bullock.

Diagnostic features distinguishing Hintonia within the Rubiaceae include its often intricate inflorescences, bearing numerous small, pinkish-white to cream-colored flowers with prominent, exserted stamens and distinctive, narrowly cylindrical corollas that are slightly flared at the throat. The ovary is typically inferior, topped by a long style and bilobed stigma. Leaves are generally opposite or whorled, simple, and possess domatia (tiny hair-filled pits) in the axils of the secondary veins on the lower surface, a significant morphological marker within the tribe. Mature fruits are small, indehiscent drupes (Steyermark, 1972; Loesener, 1922).

The center of diversity lies in Mexico, where species frequently occur in dry forest on limestone soils and coastal sand dunes at elevations from near sea level to moderate altitudes. Endemism within this region is high, with several species restricted to specific Mexican states, such as Guerrero, Oaxaca, and Chiapas (Miller et al., 1999). Biogeographically, Hintonia is part of the Mexican transition zone, showing patterns shared with other dry forest elements.

Intrinsic biological details are less comprehensively documented in accessible sources. While pollination likely involves insects attracted to the flower structure and color, direct evidence is scarce. Dispersal mechanisms for the drupes are probably endozoochorous (via animals), though specific agents remain unrecorded (Miller et al., 1999). No specific chromosome counts are available in the consulted sources.

Taxonomic circumscription exhibits complexity. Some treatments recognize Hintonia distinct from Hintonia (Bullock, 1939), while others significantly broaden Hintonia, synonymizing Hintonia species including H. latiflora under Hintonia (Millspaugh & Chasewood, 1913). Current consensus (POWO, 2024; WFO, 2024) maintains Hintonia as a valid genus distinct from Hintonia, though Hintonia remains an accepted name in major databases (POWO, 2024; GBIF, 2024), indicating unresolved synonymy. Internally, subgeneric or sectional divisions are not clearly defined in recent sources.

Human relevance remains limited. Its ornamental potential, particularly for the attractive inflorescences of some species like H. latiflora, is noted but underexploited. It is not a major timber, crop, or significant weed species.

Conservation outlook highlights knowledge gaps. Many species have restricted distributions and occur in fragmented habitats prone to deforestation. Formal conservation assessments are lacking (Miller et al., 1999). Urgent research into population status, threats, and clarification of taxonomic boundaries is needed for effective conservation planning.

Pick a Species to see its components: