Joinvillea ascendens ssp. ascendens, a member of the Joinvilleaceae (joinvillea) family, is an erect herb, 1.5 to 5 m (5 to 16 ft) tall. Leaf blades are narrowly elliptic, 45 to 80 cm (18 to 32 in) long, 4.5 to 16 cm (2 to 6 in) wide. Both leaf surfaces have scattered bristles, with the lower surface also sparsely to moderately pubescent (hairy). Tepals (a combination of petal and sepal, a leaf-like appendage) in this endemic subspecies usually split with age, the outer ones ovate to orbicular-ovate, 2.7 to 4 mm (0.1 to 0.16 in) long, with a sharp abrupt point to the apex, and inner tepals (sepals and petals that look alike) 2.6 to 3.5 mm (0.1 to 0.14 in) long. Fruit are 4.6 to 5.8 mm (0.18 to 0.2 in) in diameter and the styles (the elongated part of the female reproductive organs) are not evident on them.