Tillandsia nathanii E. H. Souza & Leme 2022, sp. nov.
Creators: name: Souza, Everton Hilo De
name: Cavalcante, Brayan P.
name: França, Rivã Ribeiro Do N.
name: Aona, Lidyanne Y. S.
name: Souza, Fernanda V. D.
name: Leme, Elton M. C.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Poales
Bromeliaceae
Tillandsia
Tillandsia nathanii

description: Tillandsia nathanii E.H.Souza & Leme, sp. nov. (Figs. 1, 2D–F, 3 H-N, 5).
Diagnosis:— This new species is morphologically similar to T. mantiqueirae, but can be distinguished from it by its smaller size (7–9.2 × 6.5–8.5 cm vs. 25–35 × 10–15 cm), more numerous leaves (48–60 vs. 30), shorter peduncle (4–6.5 cm long vs. 5–10 cm long), which are exceeded by the leaves or rarely exceeding them (vs. exceeding the leaves), and spathulate petals (vs. lingulate).
Type:— BRAZIL. Rio de Janeiro: Petrópolis, Secretário, Pedro do Rio district, 15 November 2020, N. M. G. David 02 (holotype HURB).
Plant rupicolous, heliophyte, caulescent, forming clumps, 7–9.2 cm long, 6.5–8.5 cm in diameter; stem curved, 0.4– 0.6 cm in diameter, internodes 0.2–0.3 cm long. Leaves 6–7.5 cm long, 48–60 in number, upward secund, cinereous, densely lepidote on both sides, trichomes completely obscuring the green color of the leaves; sheath slightly distinct from the blade, broadly ovate, 0.9–1.2 × 1–1.2 cm, pale-green, white lepidote; blade narrowly triangular, involute, fleshy, 5.1–6.3 × 0.5–0.7 cm, completely covered by white trichomes. Peduncle 4–6.5 cm long, 0.2–0.35 cm in diameter, exceeded by the leaves or rarely exceeding them, pale greenish, slender, completely covered by the peduncle bracts, lepidote; peduncle bracts 2–3 in number, partially imbricate, completely concealing the peduncle, foliaceous, 2–3.1 × 0.5–0.7 cm, the upper ones lanceolate. Inflorescence (fertile portion) a simple spike, 1.9–2.5 × 1.5–1.8 cm, with 4–6 flowers, horizontal to upward oriented. Floral bracts ovate to elliptic, the proximal ones long acuminate, the distal ones to acute, 1.6–1.9 × 0.6–0.9 cm, pale-rose, exceeding the sepals, nerved, membranaceous, ecarinate, sparsely lepidote adaxially, glabrous abaxially. Flowers sessile, polystichously arranged, 1.5–1.7 cm long; sepals narrowly ovate, acute, 0.9–1.1 × 0.3–0.4 cm, pale-green, membranaceous, inconspicuously nerved, the adaxial ones connate for 1/2 of their length, glabrous; petals spathulate, 1.4–1.6 × 0.7–0.8 cm, rounded, free, the blade spreading to reflexed, whitish. Stamens included, 0.9–1.1 cm long; filament flattened, flaccid, plicate, sublinear, whitish, slightly translucent, free; anther pale yellowish, 1.5–2.5 × 0.25–0.3 mm, basifixed. Pistil equaling the stamens; ovary pale greenish, ovoid, 2–2.5 × 1.7–1.8 mm; style erect, whitish, 0.9–1.1 mm long, 0.3–0.4 mm in diameter; stigma simpleerect. Capsules and seeds not seen.
Etymology:— The specific epithet honors Nathan Miranda Gazineu David,undergraduate biologist, conservationist and currently curator of the Bromeliad collection of Ivo de Azevedo Penna, who informed us about the existence of the population of this new species.
Phenology:— The blooming season starts in October and extends to January.
Distribution and habit:— Tillandsia nathanii was found growing on granitic outcrop in the Atlantic Forest at an altitude of 1,433 m in Secretário, in the district of Pedro do Rio, Petrópolis municipality.The Secretário is a mountainous region, with numerous granitic outcrops surrounded by Atlantic Forest. The regional climate is high-altitude tropical, with hot and humid summers, and relatively cool, dry winters. The high relief, formed by high-altitude mountains, has a great influence on the climate of the municipality, forming masses of hot-humid air that are blocked, concentrated and forced to rise to high altitudes. The population of T. nathanii grows on the most vertical part of the rock, fully sun exposed, without any organic substrate. The population in the three granitic outcrops seen are composed of sparsely scattered specimens or forming clumps of three to eight individuals of different stages of development.
Conservation status:— Tillandsia nathanii is an endemic species with a restrict area of occurrence, only found on three granitic outcrops close to a highway being surrounded by a deforested area, not protected by any conservation unity. Beside this, periodical fires, criminal extractivism for regional and international illegal trade, are the main causes that seriously affect the existence of this new species.
Based on the IUCN criteria and the limited geographic range of the species, the GeoCAT (geocat.kew.org) evaluated that the area of occupancy (AOO) a is 12,900 Km², classifying the species as critically endangered [CR B2ab (i, ii, iii, iv)], threatened by habitat fragmentation and fast population decline.
Observations:— Tillandsia nathanii belongs to subg. Anoplophytum, being morphologically related to T. mantiqueirae Paixão-Souza et al. (2021: 196) and T. recurvifolia Hooker (1861: 5246). In relation to T. mantiqueirae, this new species differs from it by its smaller size when in bloom, with a smaller diameter, leaves more numerous shorter peduncle, and spathulate petals (see diagnose and Table 2).
Tillandsia nathanii can also be confused with T. recurvifolia, a species from São Paulo southward into Argentina, Bolivia and Paraguay (Paixão-Souza et al. 2021), but it is clearly distinct by its smaller size when in bloom (7–9.2 cm long vs. 15–25 cm long), shorter and narrower leaves (6–7.5 × 5–7 cm vs. 14 × 8–11 cm), greater number of leaves (48–60 vs. 37), shorter peduncle (4–6.5 cm long vs. 7–12.5 cm long), flowers fewer (4–6 vs. 6–8 in number) and smaller (1.5–1.7 cm long vs. 3 cm long), pale-rose floral bracts (vs. pink) (Table 2, fig. 5).
Tillandsia stricta Solander ex Sims (1813: 1529) of subg. Anoplophytum was the only species of the genus observed living sympatrically with T. nathanii despite growing as an epiphyte in the Atlantic Forest surrounding the rocky outcrop.
description: Published as part of Souza, Everton Hilo De, Cavalcante, Brayan P., França, Rivã Ribeiro Do N., Aona, Lidyanne Y. S., Souza, Fernanda V. D. & Leme, Elton M. C., 2022, Two New Species of Tillandsia (Bromeliaceae: Tillandsioideae) from Brazil, pp. 93-103 in Phytotaxa 560 (1) on pages 99-101, DOI: 10.11646/phytotaxa.560.1.7, http://zenodo.org/record/7031263