Uncaria callophylla Blume ex Korth.
Korthals. P.W. (1842) Verh. Nat. Gesch. Bot. 5: 170. Type: Borneo.
Vine stem diameters to 14 cm recorded. Stem vessels very large, readily visible to the naked eye. Stem pith square in transverse section.
Leaf blades about 8-11.5 x 3-5 cm, petioles about 0.5-1 cm long. Domatia are tufts of hair surrounding or bordering a slit-like foveole or gash. Stipules entire, about 5-9 mm long, blunt at the apex. Hooks or tendrils develop from short shoots in the leaf axils and resemble shepherd's crooks about 2-2.5 cm long.
Fruits longitudinally ribbed, borne in umbels of 50-60 fruits. Each fruit clavate or spindle-shaped, about 10-20 x 3-3.5 mm on a stalk about 5 mm long. Calyx lobes linear, twisted, persistent at the apex, about 1 mm long. Seeds numerous, each seed two-winged. Seeds about 0.2-0.3 mm long, seed + wing about 4-5 mm long. Embryo about 0.1-0.2 mm long. Radicle longer than the cotyledons.
Features not available.