Rosette dense, funnel-shaped, upright. Leaves 25-50 cm long, 3-5 cm wide, glossy green above, pale scaled beneath; broadly rounded with a short spined tip; margins almost entire or with a few small spines near the tip. Inflorescence simple, cylindrical, many-flowered, on a slender green scape; floral bracts narrowly triangular, spine tipped, entire. Flowers to 1.5 cm, purplish-red, stalkless, sepals united for half their length, red; petals blue to purple.
A.gamosepala is in the subgenus Ortgiesia (Group 4).
Source: (2005). Bromeliaceae. In: . Horticultural Flora of South-eastern Australia. Volume 5. Flowering plants. Monocotyledons. The identification of garden and cultivated plants. University of New South Wales Press.