Rosette slender, upright. Leaves to 60 cm long, 5 cm wide, stiff, grey scaled, sometimes banded beneath; tip broadly pointed or rounded, margins with short brown spines. Scape upright, slender, white woolly. Inflorescence paniculate, 10-12 cm long, white woolly with red spine-tipped bracts. Flowers stalkless with blue petals and small pink floral bracts; sepals united for one third of their length, woolly, greenish-pink; ovary white woolly.
A. coelestis is in the subgenus Ortgiesia (Group 4)
var. albo-marginata M.B. Foster is distinctive with leaves having a defined white marking and is more common in cultivation.
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.