Decarya is a monotypic genus of flowering plants in the family Didiereaceae, within the order Caryophyllales. It contains a single species, Decarya madagascariensis, a spiny shrub or small tree endemic to southern Madagascar that grows up to 6 metres in height, with distinctive zig-zagging branches covered in short spines.
The genus was described by the French botanist Choux, with the species first published in 1934. It commemorates Raymond Decary (1891–1973), a French botanist, ethnologist and colonial administrator who carried out extensive research in Madagascar and collected specimens for the National Museum of Natural History, France. At publication, the name was explicitly distinguished from the similarly spelled genus "Decaryia," an orthographic confusion still reflected in taxonomic databases today.
Decarya madagascariensis is native to the Atsimo-Andrefana, Androy, and Anosy regions of southern Madagascar, occurring between the towns of Toliara and Tolagnaro. It grows in dry spiny thicket or forest, and in degraded thicket on limestone substrates, from sea level up to 400 metres elevation. It is a characteristic member of Madagascar's spiny forest ecosystem, often found growing alongside species of Didierea and Euphorbia — fellow succulent, drought-adapted plants of the same arid, thorny habitat.
The species faces conservation pressure from habitat destruction, driven by human-caused fires, land clearance for agriculture and pasture, and over-harvesting for charcoal production. Its population is thought to be declining, and the IUCN Red List assesses it as Near Threatened.
Etymology
Named after Raymond Decary (1891–1973), a French botanist, ethnologist and colonial administrator who conducted research in Madagascar and collected specimens for the National Museum of Natural History, France.
Distribution
Endemic to southern Madagascar, occurring in the Atsimo-Andrefana, Androy, and Anosy regions between Toliara and Tolagnaro.
Ecology
Grows in dry spiny thicket or forest and in degraded thicket on limestone, from sea level to 400 m elevation, often alongside Didierea and Euphorbia species within Madagascar's spiny forest ecosystem.
Conservation
Assessed as Near Threatened on the IUCN Red List; threatened by habitat destruction from human-caused fires, land clearance for agriculture and pasture, and over-harvesting for charcoal, with a population thought to be declining.
Taxonomy Notes
Placed in family Didiereaceae, order Caryophyllales. Described by Choux, published 1934 (with an earlier note in 1929); the original publication explicitly distinguished the name from the similarly spelled genus "Decaryia," a confusion still reflected in some taxonomic databases, which list "Decaryia madagascariensis" as a doubtful synonym-like entry.
