PlantaeDB Logo
Login Sign-up

Genus Vallesia in Tribe Aspidospermateae

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!

Vallesia (Apocynaceae, Rauvolfioideae) is a small American genus of shrubs and small trees with about nine species, distributed from the southern United States through Mexico and Central America to the northern Andes and the Caribbean. The name is typified by V. glabra, which remains the accepted type in current practice (POWO, 2024; WFO, 2024; The Plant List, 2013). Members are typically evergreen shrubs with milky latex. Leaves are simple, opposite or whorled, often leathery, and lack conspicuous stipules. Inflorescences are cymes or thyrses borne in the leaf axils or at branch tips. Flowers are small, with a tubular corolla that is usually white to cream; the corolla lobes are valvate, and the corolla throat is often bearded or fornicate. The gynoecium has a superior, apocarpous ovary with two separate carpels that may be apically connate by the styles; fruit comprises twin drupes or occasionally a single drupe when one carpel aborts. Seeds lack obvious wings and are passively dispersed by birds and other vertebrates that consume the fruit (Endress et al., 2014; MUNZ, 2014).

Centers of species diversity lie in Mexico and the Caribbean, with a number of narrowly endemic taxa on islands such as the Galápagos (for V. coerulea). Typical habitats include tropical dry forest, shrublands, dunes, and coastal thickets from sea level to mid-elevations. Some species, notably V. antillana, occur as ruderal shrubs along roadsides and in secondary growth (MUNZ, 2014).

Pollination and dispersal are typical for Rauvolfioideae: flowers are likely entomophilous (small moths or flies), and fruits are dispersed by frugivorous birds and other animals (Endress et al., 2014). Reported chromosome counts from islands and mainland taxa are consistently x = 11 (Rice et al., 2015; Ebase et al., 2021).

Taxonomically, Vallesia has been maintained as a coherent genus in major treatments (e.g., Leeuwenberg, 1994). Most floras do not divide it into subgenera or sections. Nomenclatural changes at species level—particularly around V. ovata and related names—have created unstable synonymy across checklists, so counts and species limits differ among sources (POWO, 2024; WFO, 2024). Where V. ovata is placed, different authors recognize a distinct Galápagos species (V. coerulea) or treat it within a broader V. ovata complex; this circumscription remains unresolved (MUNZ, 2014). No alternative major classification conflicts with the genus concept itself (APG IV, 2016).

Several species are cultivated or occur naturally in xerophytic landscaping and erosion control due to their drought tolerance and attractive foliage; V. antillana is a frequent component of coastal scrub. No species is widely invasive on a continental scale (MUNZ, 2014; WFO, 2024).

Limited field work on island and coastal populations and ongoing revision of V. ovata complex synonymy hinder precise species counts and threat assessments. Continued targeted surveys and integrative taxonomic work are needed to refine species limits and conservation priorities.

Pick a Species to see its components: