The new species is similar to Tillandsia parryi but differs in the width of the leaf blades (6–7 × vs. 3.5–3.7 cm in Tillandsia parryi), in the rachis exposure in mature spikes (not exposed vs. exposed), in the color of the floral bracts (bicolored, vinaceous at the apex, green at the base vs. unicolored, red to orange), in the floral bracts form and keel (obovate to oblong, ecarinate vs. elliptic to narrowly elliptic, carinate at the apex), and in the width of the sepals (1.1–1.3 vs. 0.75–1 cm).
TYPE:— MÉXICO. Querétaro: municipio de Ezequiel Montes. Acantilados de la Peña de Bernal (20°44’53.88”N, 99°56’43.10”W), 2,265 m, March 3, 2022, R. Hernández-Cárdenas 2607 (holotype UAMIZ!, isotype MEXU!).
Plants saxicolous, in flower ca. 87 cm tall; rosettes acaulescent, 55– 50 cm high, 60–75 cm in diameter, solitary or forming clumps of two to four rosettes. Leaves more than 20; sheath pale brown on both surfaces, oblong to ovate, 15–18 cm long, 6–11 cm wide, glabrous near the base and lepidote distally on both surfaces; blade pale green, narrowly triangular, 45–60 cm long, 6–7 cm wide, long attenuate, lepidote on both surfaces. Inflorescence terminal, erect, once branched of 16–20 sub-erect to ascending spikes; peduncle pale brown, terete, 4–8 cm long, 0.8–1.5 cm in diameter, glabrous, fully covered by the sheaths of the peduncle bracts, internodes 2–3 cm; peduncle bracts pale green, foliaceous, gradually decreasing in size distally, exceeding the internodes, lepidote on both surfaces, imbricate; axis red, pale brown when dry, terete, 25–28 cm long, 0.5–1 cm in diameter, glabrous, internodes 1.5–3 cm long; primary bracts vinaceous to reddish-green, pale brown to gray when dry, the sheath ovate, 3–5 cm long, 1.5–2.5 cm wide, the blade triangular to linear, gradually decreasing in size distally, the lower ones much exceeding the spike by the blade, the distal ones shorter than the spike, glabrous near the base and lepidote distally on both surfaces. Spikes flattened to subterete, distichously 5–12-flowered, 13–18 cm long, 1.4–1.8 cm wide; stipes terete, 4.5–5.5 cm long, 0.3–0.4 cm in diameter, glabrous, bracteate; stipe bracts 2–3, elliptic, 2.5–3 cm long, 1–1.2 cm wide, glabrous, nerved; rachis greenish red, pale brown when dry, terete, 1–2 mm in diameter, covered by the floral bracts, internodes 7–8 mm long; floral bracts green at the base, dirty vinaceous toward the apex and margins when fresh, obovate to oblong, 3–3.5 cm long, 1.5–1.7 cm wide, over four times longer than the internodes, exceeding the sepals, imbricate, acute, glabrous on both surfaces, nerved, ecarinate. Flowers appressed to the rachis, actinomorphic; corolla tubular, more slender at the base; receptacle 1–2 mm long; sepals free, green, narrowly elliptic, 2.8–3.0 cm long, 1.1–1.3 cm wide, acute, hyaline at the margins, the adaxial ones slightly carinate; petals free, white toward the base, violet in upper (exposed) part, narrowly oblanceolate to spathulate, 5–5.2 cm long, 0.8–0.95 cm wide, rounded at the apex, the apical margins slightly recurved, corolla apex constraining the filaments; stamens subequal, exserted; filament free, twisted, white toward the base, green distally, flat at the base, dilated, fleshy and subterete in the distal part, filiform, 5.5–5.8 cm long, 0.6–1.5 mm wide; anther black, narrowly oblong to narrowly elliptic, 3–3.3 mm long, 1.0– 1.2 mm wide, sub-basifixed; ovary green, narrowly conic to narrowly ovoid, 9–10 mm long, 4–6 mm in diameter; style green, filiform, 5.5–6 cm long, 1–1.3 mm wide, equaling to exceeding the stamens; stylar branches dirty light-purple, conduplicate-spiral, ca. 3 mm long. Fruits unknown.
Distribution and habitat: — Tillandsia bernalensis is only known from the type collection at the Peña de Bernal monolith, in the municipality of Ezequiel Montes, in the state of Querétaro (Fig. 1) that is part of the biogeographic province of the Chihuahuan desert (according to Morrone et al. 2017). The Peña de Bernal is a dacite Mesozoic monolith with a porphyritic structure composed mainly by plagioclase and hornblende crystals, and is isolated from the rest of geological formations, promoting the presence of endemic plant species (Aguirre-Díaz et al. 2013). The new species grows saxicolous on vertical rock walls where xerophilous scrub (according to Rzedowski 1978) with species of Agave, Hechtia, Fabaceae, and Opuntia predominates. Tillandsia bernalensis grows at elevations between 2,250 and 2,290 m a.s.l. and blooms from March to April.
Etymology: —Specific epithet refers to the porphyritic monolith Peña de Bernal, on whose cliffs the new species grows.
Observations: — Tillandsia bernalensis also has some similarities with T. suesilliae and T. tonalaensis. However, T. bernalensis differs from T. suesilliae in the width of the spikes (1.3–1.8 vs. 1.7–2.3 cm), in the length of the floral bracts (3–3.5 vs. 3.9–5 cm), in the size of the sepals (2.8–3 × 1–1.2 vs. 3.4–3.5 × 0.9–1 cm), and in the color of the petals (violet vs. green), amongst other differences (see Table 1). Tillandsia bernalensis can also be confused with T. tonalaensis but differs from it in the shape of the floral bracts (obovate to oblong vs. ovate to lanceolate), in the size of the sepals (2.8–3 × 1–1.2 vs. 3–3.5 × 0.8–1), and in its geographical distribution (Guanajuato vs. Oaxaca), see also Table 1 and Figure 3.