Herbs, monocarpic, purple-mottled, glaucous. Stems mostly simple, terete, 5-25 dm × 0.5-2 cm. Leaves opposite, evenly spaced, simple, largest subpeltate; petiole subterete, 1-5 cm; blade purple-blotched abaxially, triangular to lanceolate, 5-25 × 3-12 cm, margins serrate, apex acute, surfaces glaucous; bulbils borne in notches of leaf margins, spurs spoon-shaped. Cymes lax, paniculate, 1.5-3 dm diam.; branches to 15 cm. Pedicels 5-15 mm. Flowers: calyx green or purplish, not inflated, 6-10 mm, tube 3-4 mm, lobes triangular, 3-7 mm, equaling or longer than tube, apex acute; corolla pink or lavender, 20-30 mm, not contracted basally, lobes obovate, 6-12 mm, apex rounded, apiculate. 2n = 38.
Flowering winter. Waste ground, mesquite-cactus thickets; 0 m; introduced; Fla., Tex.; Indian Ocean Islands (Madagascar).
Bryophyllum daigremontianum is well established and an aggressive weed in southern Florida and in coastal southern Texas. M. G. Groner (1975) found that exudates of its roots can inhibit the growth of nearby plants, as can extracts of its shoots. The entire plant contains bufadienolides and is toxic to cattle (R. A. McKenzie et al. 1987).
The hybrid Bryophyllum daigremontianum × B. delagoense is much like B. daigremontianum but with narrower leaves; some specimens identified as B. daigremontianum may possibly be the hybrid. The hybrid is widely naturalized in Queensland.