Plant 15-25 cm tall. Leaves scaled; sheaths broadly ovate, strongly inflated forming a bulb, merging into the blades; blades linear-triangular, inrolled-awl-shaped to 15 mm wide. Scape erect with leaf-like bracts. Inflorescence simple or digitate; spikes 2-6, erect to spreading, linear-lanceolate to 18 cm long, 6-12 flowered; floral bracts overlapping, to 2 cm long, equalling or slightly exceeding the sepals, almost hairless, red, pink and green; sepals hairless; petals 3-4 cm long, violet, forming a tube; stamens protruding.
Mexico and Central America
T. bulbosa Hook. from Mexico, West Indies to Ecuador and Brazil is stemless, growing in clumps, and very variable in size and colour. Leaves 8-15; sheaths orbicular, abruptly contracted into the blades, greatly inflated, 2-5 cm long forming dense ovoid bulbs, green or greenish-white, often with a narrow red or purple marginal band; blades involute-subulate, spreading, to 30 cm long, 2-7 mm wide. Scape erect with upper scape bracts often red. Inflorescence simple or digitate from a few spikes, red or green; spikes spreading, flattened, 2-5 cm long, 2-8 flowered; floral bracts 15 mm long, exceeding the sepals, finely scaled; sepals 13 mm long, hairless; petals 3-4 cm long, blue or violet, forming a tube; stamens protruding.
T. exserta Fernald from north-west Mexico has many leaves in a dense rosette to 30 cm long, grey scaled; sheaths ovate, conspicuous; blades very narrowly triangular, 3-4 mm wide, recurving. Scape erect with leaf-like bracts at base and upper ones elliptic. Inflorescence simple or digitate to 18 cm long; spikes erect, linear-lanceolate, 5-14 cm long, 8-15 mm wide, flattened, about 12 flowered; floral bracts densely overlapping, 2 cm long, distinctly shorter than sepals, often red, densely scaled; petals 35 mm long, violet, forming a tube; stamens protruding.
T. neglecta E. Pereira from south-eastern Brazil has leaves many-ranked, somewhat curved, triangular-subulate, 4-7 cm long, both sides scaled; sheath 15 mm wide. Scape erect, totally covered by ovate-oblong, long-acuminate bracts. Inflorescence simple, many-ranked, 6-10 flowered, 3-4 cm long; floral bracts ovate, almost hairless, as long as, or a little longer than the sepals; sepals hairless, 15-16 mm long, united for 2 mm; petals blue, 22-30 mm long, tip reflexed; stamens included.
T. paucifolia Baker from Florida,West Indies, Mexico, Central America, Colombia and Venezuela has leaves thick, covered with grey scales; sheaths large, broadly ovate, forming a narrowly ovoid pseudobulb 5-15 cm long, merging gradually into the blades, the outer ones much reduced and bladeless; blades involute-subulate to 20 cm long, 3-7 mm wide, curved or coiled. Scape erect with leaf-like bracts. Inflorescence simple or pinnate; spikes erect, linear-lanceolate, to 12 cm long, 2-10 flowered; floral bracts 2-3 cm long, exceeding the sepals, appressed scaled; sepals lanceolate-oblong, almost hairless; petals erect, to 4 cm long, violet, forming a tube; stamens protruding.
T. pseudobaileyi C.S. Gardner from Mexico has leaves 10-12, forming a bulbous rosette; sheath 4-5 cm long, 5-6 cm wide, inflated, nerved; blade 20-35 cm long, 1-1.5 cm wide, arching, divergent, involute. Scape to 15 cm long, blood red; bracts overlapping with long-involute blades. Inflorescence compound; spikes 2-5, narrowly lanceolate, 4-6 flowered, spreading 40-45°; floral bracts ovate, 17-20 mm long, 9-11 mm wide, hairless except for tip, exceeding the sepals; sepals free, hairless, green with red edges; petals about 3 cm long, lavender, forming a tube; stamens protruding.
T. streptophylla Morren from southern Mexico to Honduras has leaves 60-80, forming a dense pseudobulb to 8 cm wide, 50 cm long with coarse grey scales; sheaths broadly ovate to 10 cm long; blades narrowly triangular, the outer ones recurving, 2-3 cm wide; scape erect with leaf-like bracts, the upper ones with red sheaths. Inflorescence pinnate, laxly pyramidal to 30 cm long, axes bright red, densely scaled; spikes erect to spreading, 8-18 flowered, 8-23 cm long, 15-18 mm wide, flattened; floral bracts 2-3 cm long, exceeding the sepals, 8-13 mm wide, densely scaled, green; sepals hairless; petals 35-40 mm long, purple, forming a tube; stamens protruding.
T. tricolor Schltr. & Cham. from southern Mexico and Central America has many leaves in a dense rosette, scaled; sheaths large; blades linear-triangular, 1 cm wide at base; waxy green. Scape erect with leaf-like bracts, the upper ones red. Inflorescence simple, distichous, or laxly digitate; spikes erect, linear-lanceolate, 6-18 cm long, 18-25 mm wide, strongly flattened; floral bracts densely overlapping, 3 cm long, 18 mm wide, hairless, much exceeding the sepals; sepals hairless; petals 7 cm long, violet. T. tricolor var. melanocrater (L.B. Sm.) L.B. Sm. has a flowering stem less than 25 cm high.
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.