Plant growing saxicolously, stemless but with long rhizomatous base, 40-60 cm high, to 50 cm wide, few leaves (10 to 20 in number) form a narrow, suberect, funnelform rosette with basal offshoots. Leaves 30-60 cm long, very stiff and coriaceous, sub-succulent, brown, adaxially dark brown, bearing minute, appressed, brown-centered scales throughout. Blades 4-7 cm wide at base, to 50 cm long, sub-triangular, attenuate, nearly erect, green, densely and finely adpressed lepidote, nerved, abaxially strongly nerved. Scape shorter than the rosette, to 20 cm long, stout, to 1 cm in diameter, erect at base, then curved or subdecurved, imbricately concealed by few, foliaceous, erect scape bracts, the triangular blades slightly spreading, the upper ones becoming rose. Inflorescence pendent or subpendent, 30 to 50 cm long, to 25 cm wide, laxly bipinnate, composed of 7 to 15 branches, internodes 2-2.5 cm, spreading 45-75 degrees, axis stout, slightly flexuous, glabrous, red like the primary bracts. Primary bracts much shorter than the spikes, the basal ones about 1/3 as long as the spike, the apical ones only slightly longer than the floral bracts, mostly only as long as the sterile bracteate base of the branch, and enfolding it, to 7 cm long and 3 cm wide, ovate, acute, the basic ones caudate, adaxially green, strongly nerved, abaxially red, lustrous, glabrous, slightly nerved. Spikes 5-16 cm long, 2.5-3 cm wide, stipe 1-4 cm long, narrowly elliptic, acute, complanate, distichously composed of 6 to 11 flowers with 2 to 4 sterile bracts at base, and a strongly bicarinate bract adjacent rhachis, rhachis glabrous, nearly straight,· flowers subsessile, odorless. Floral bracts densely imbricate, concealing the quadrangular, slightly flexuous, glabrous rhachis, 3.2-4.3 cm long, equaling the sepals, 1.7-2.2 cm wide, ovate, acute, enfolding the sepals, ecarinate, coriaceous, adaxially strongly nerved, abaxially rose. Sepals 3-:4 cm long, 10-13 mm wide, elliptic, acute, yellow-green, nerved, the margins sub-hyaline, the posterior ones slightly carinate and short connate (1-2 mm). Petals 5-5.2 cm long, 7 mm wide, ligulate, erect, their tips slightly revolute, corolla throat closed around the filaments, blackish-violet, basal 2/3 white. Stamens exserted. Filaments 5-5.5 cm long, in two series of unequal length, 0.8 mm wide near apex, yellow-green, becoming white and thin at base, anthers 3 mm long, 1 mm wide, versatile fixed 1/4 from base, olive-green, pollen egg-yellow. Style 4.5-5 cm long, greenish-white, light violet towards apex. Stigma very small, 1 mm long, 1 mm wide, lobes dirty violet, erect, not spreading, once twisted, Type 1 of Brown & Gilmartin (1984). Ovary 8 mm long, 3.5 mm wide, conical, green.
Tillandsia atroviolacea seems to be related to Tillandsia pamelae from which it differs by the following characters: Leaves more succulent, coriaceous and stiff, not cretaceous, sheaths distinct, dark brown, contrasting with the blade, blades sub-triangular not ligulate; primary bracts ovate, not cretaceous; spikes more complanate, composed of fewer flowers, the internodes between the flowers longer; floral bracts equaling the sepals, without hyaline margins, not at all lepidote nor cretaceous; sepals narrower, the posterior ones short connate, not cretaceous nor lepidote; petals shorter but wider.