Perennial herb or shrub, up to 500 mm tall. Leaves 8-35 x 1-5 mm, lanceolate or linear-lanceolate, margins revolute, woolly or cobwebby above, white-woolly below. Heads cylindric or narrowly campanulate, many in cymose clusters arranged in a compact, sometimes lax, terminal corymbose panicle. Flowers yellow; involucral bracts tawny or innermost yellowish.
H. melanacme is closely allied to H. tenuiculum but is distinguished by its leaves, which are nearly always woolly or cobwebby above, and its heads with involucral bracts tawny (or very rarely the innermost yellowish), tips always decidedly crisped, and more numerous flowers, (15-)20-45, 6-18 female, 12-32 homogamous.
Closely allied to H. tenuiculum, but differs by: Leaves ± always woolly or cobwebby above. Involucral bracts tawny, apex always clearly crisped. Flowers 15-45. Flowering time Dec.-Apr.