Endostemon tenuiflorus is a species of flowering plant in the family Lamiaceae and commonly called the slenderleaf keepsafe or, sometimes in South Africa, the mopaneveld keepsafe.
This species is a perennial, softly sticky dwarf shrublet tall, woody at the base and freely branched. The stems are ascending and covered with fine glandular bristles.
The leaves are subsessile and often leathery, with linear to linear-oblanceolate blades, long. The surfaces are roughened by numerous sunken glands, with blunt tips, narrowed bases, and margins that are obscurely and distantly toothed, often rolled under.
The inflorescences are lax racemes long, composed of several spaced whorls, each bearing two flowers. The bracts are long. The calyx is spiny and strongly veined, hairy within the throat, and enlarges to about at maturity; the tube is bell-shaped, with narrow, awl-shaped lateral teeth shorter than the lower pair. The corolla is whitish to mauve or pink, long, with a cylindrical tube and short lobes.
In northeastern Africa, Endostemon tenuiflorus looks closest to Endostemon glandulosus in Ethiopia. The latter has a shorter inflorescence, however, and its corolla is five-lobed.
Endostemon tenuiflorusâ²s geographic range spans southern Africa, northeastern tropical Africa, southern Madagascar, Socotra, and the Arabian Peninsula. In southern Africa, it has been recorded in northwestern Namibia, Botswana, southernmost Zimbabwe, and South Africaâ²s Limpopo and Mpumalanga provinces. It tends to be found in drier savannah, including AcaciaâÂÂCommiphora bushland and Zambezian and mopane woodlands.