Katustes

Katustes is a small, monotypic genus of flowering plants in the family Rubiaceae, described here as endemic to the western Amazon basin. The sole species is Katustes amazonica.

Description: Katustes amazonica is an evergreen tree typically reaching 5–8 meters in height. It has opposite, elliptic leaves with a glossy surface. Inflorescences are terminal panicles bearing white to pale pink flowers, followed by globose red berries about 6–9 millimeters in diameter, containing one to two seeds.

Distribution and habitat: Known from isolated occurrences on nutrient-rich river floodplains and adjacent terra firme forests in southern Peru and western Brazil. It is associated with lowland tropical rainforest habitats at elevations roughly 50–300 meters.

Ecology: The species is pollinated by bees and hummingbirds, with seed dispersal by large frugivorous birds such as toucans. It tends to occur in edge and gap habitats within the forest, often in proximity to nutrient-rich soils and seasonal flooding regimes. Mycorrhizal associations are suspected but not fully documented.

Taxonomy and etymology: The genus name Katustes is derived from a local term katuste, used by nearby communities to describe forest features believed to harbor spirits in traditional belief systems. The species epithet amazonica reflects its Amazonian distribution. The taxon was described by botanist A. N. Silva in 1992.

Conservation and uses: Katustes amazonica is assessed as Critically Endangered due to habitat loss from logging, mining, and agricultural expansion. Only a few subpopulations are known, with limited and fragmented habitat. In local traditional medicine, leaves are used in decoctions, but pharmacological evidence is limited. Ex situ cultivation exists in two regional botanical gardens.

See also: Rubiaceae, plant conservation, Amazon rainforest flora.