The bulbs are solitary or form small clusters, evergreen, usually just below the soil or rarely above the substrate. The bulb is egg-shaped, 70 × 55 mm, the bulb scales (tunics) fleshy, and truncate, also arranged like tiles on a roof (imbricate). The bulb scales drying greyish, with a fibrous network. The roots are fleshy, white, up to 3 mm in diameter. The leaves are oblong, linear-attenuate, 300–550 × 20–30 mm, in a rosette, drooping, semi-succulent, firm, dark green, smooth, faintly striate, and channelled for most of their length, the tip sharp (apex acute).

Fig. 2 . Albuca thermarum in habitat at Badspoort. Note the fleshy striate leaves and truncated bulb scales.

The inflorescence is a spreading to pendulous raceme, 400–600 mm long, the peduncle grows up to 260 mm long, the bracts acuminate, 45 × 8 mm, green with white translucent margin. The base of the inflorescence (scape) 8–10 mm in diameter. The individual flower stalks (pedicels) ascending to erect, up to 105 mm long at base, becoming shorter, up to 35 mm long near tip. The individual flowers erect, 20 mm long, with yellowish green tepals of which the tips are yellowish to yellowish green becoming white The stamens grow to about 15 mm long, 2 mm in diameter at base (flattened); inner 13 mm long, with distinct short channelled constriction 4.5 mm from base, basal third broadly triangular-ovate (3mm wide at base), margin membranous, apices of both inner and outer filaments projected forward and adpressed against style; anthers oblong, versatile, outer 2.5 × 1.5 mm, inner 3.5 × 2.5 mm. The female portion (ovary) oblong, 3-angled, 7 × 4 mm, stipitate for 1.5 mm, each angle with raised emarginate base; style linear-trigonous, clavate, 9 × 2 mm; stigma yellowish green. The fruiting capsule 18 × 10 mm, grey-brown, valves splitting in distal quarter. The seeds flat, 6 × 3 mm, angular, distinctly wrinkled, blackish brown.

Albuca thermarum flowers mainly during late spring (October and November). The seeds are normally released in early summer, towards the end of November to early December and are dispersed by the wind.

Fig. 3. Illustration of Albuca thermarum by Vicki Thomas, drawn from a plant flowering at Kirstenbosch National Botanical Garden. Note the yellow tipped flowers.