Tillandsia leucopetala H. Büneker, R. Pontes & L. Witeck, 2015

Büneker, Henrique Mallmann, Pontes, Rodrigo Corrêa, Witeck-Neto, Leopoldo & Soares, Kelen Pureza, 2015, Tillandsia leucopetala, a new species of Bromeliaceae from Rio Grande do Sul, southern Brazil, Phytotaxa 202 (2), pp. 143-148 : 144-147

Tillandsia leucopetala H. Büneker, R. Pontes & L. Witeck , sp. nov. ( Figs. 1 A–H , 2 A–C , 3)

Species morphologice proxima Tillandsia toropiensis et Tillandsia nuptialis , a prima differt apparentia maiori quando florita (usque 45 cm vs. usque 30 cm longa), maiori magnitude laminarum foliarium (usque 30 cm vs. usque 20 cm longis) et pedunculi (usque 30 cm vs. usque 19 cm longis), inflorescentia maiore, cum maiore numero florum (usque ad 11 cm longa et 11-flora vs. usque ad 5.5 cm longa, usque ad 7-flora), partibus perianthii maioribus (sepalis usque 2.6 cm longis, petalis usque 4 cm longis vs. sepalis usque 2 cm longis, petalis usque 3, 4 cm longis), coloribus bractearum scapalium et floralium (generaliter luteo-virentium vs. rubentium), et sepalis lepidotis (vs. glabris); eae adaxiales connatae solum usque mediam partem (vs. connata usque ad apicem) sunt. A secunda differt habitu minus caulescente, laminis foliorum maioribus (usque ad 30 cm vs. usque ad 11 cm longis), pedunculo generaliter maiori (usque ad 30 cm vs. usque ad 14 cm longo), inflorescentia maiore et maiore numero florum (usque ad 11 cm longa et 11-flora vs. usque ad 7 cm longa et 6-flora), bracteis floralibus denso-lepidotis in facie abaxiali (vs. lepidotis solum in apice faciei externae) et partibus perianthii minoribus (sepalis usque ad 2.6 cm et petalis usque ad 4 cm longis vs. sepalis usque ad 2.1 cm et petalis usque ad 3 cm longis).

Type: — BRAZIL. Rio Grande do Sul: Santiago, saxícola no Perau do Macaco Branco, em escarpa rochosa às margens do rio Jaguarizinho, ocorrendo junto a Eriocactus claviceps e Dyckia sp. , 277 m elevation, 4 July 2013, H. M. Büneker 249, R. C. Pontes & L. Witeck (holotype HDCF!; isotype US!, RB!, SMDB!).

Saxicolous plant, caulescent, flowering 15–45 cm high; roots developed, branched; stem naked or covered by remaining dead sheaths. Leaves 9–15 in number, succulent, polystichous, erect or suberect, slightly curved from the center to the apex, sometimes subsecund; sheaths 2.1–5 × 2–4 cm, ovate-elliptic, greenish-white, adaxially lepidote at the distal end, abaxially white, densely-lepidote at the apex, margins with fimbriate trichomes at the distal end; blades very narrowly triangular, canaliculate, acute, 12–30 × 0.9–2.3 cm, densely velutinous-lepidote, greenish-cinereous, basal margins with protruded larger trichomes. Peduncle erect-arcuate, 12–30 cm long, terete, greenish, sparsely lepidote in the upper portion; peduncle bracts the basal ones foliaceous, densely lepidote, the upper ones narrowly elliptic to lanceolate, attenuate-acuminate, 3–7 × 1.2–2 cm, exceeding the internodes, greenish, lepidote abaxially. Inflorescence simple, lax, 4–11 flowered, 4.3–11 cm long; rachis flattened, conspicuous, green; floral bracts 2.6–4 × 1–2.1 cm, ovate to narrowly elliptic, acute to attenuate, greenish, rose-orange in the upper portion, lepidote abaxially, the basal ones exceeding the flowers. Flowers polystichously arranged, suberect or erect, 0.3–1.5 cm apart, inconspicuously pedicellate; pedicel ca. 1 mm long; sepals 1.8–2.6 cm long, lanceolate to narrowly elliptic, acute, translucent, yellowish, reddish-green, whitish-pink, whitish-orange or whitish-green, abaxially sparsely lepidote mainly at the apex, the abaxial one ecarinate, free, the adaxial ones carinate and connate to the middle; petals 2.5–4 cm long, white, claw sublinear; blades elliptic, obtuse or rounded apex, patent at anthesis; stamens included, ca. 2.5 cm long, equaling the petal claw; filaments sublinear-complanate, plicate above the middle; ovary obovoid, ca. 5 mm long, whitish-green; stigma simple-erect.

Etymology: —The specific epithet of the new species refers to the white color of its petals (leucos = white, petala = petal).

Distribution and habitat: — Tillandsia leucopetala is currently known from the type locality only, where it was found growing saxicolous on a single steep rock in the Jaguarizinho river valley, together with other xerophytic Bromeliaceae (e.g. Dyckia sp. ), Cactaceae (e.g. Cereus hildmannianus Schumann (1890: 202) , Eriocactus claviceps Ritter (1966b: 115) , and Opuntia sp. ) and Gesneriaceae (e.g. Sinningia sp. ).

Conservation Status: — Tillandsia leucopetala is possibly endemic to the type locality and its known population has about 150 individuals. According to the criterion D1 (very small or restricted population) of IUCN (2012), it is considered an endangered species (EN).

Observations: — Tillandsia leucopetala belongs to the subgenus Anoplophytum sensu Smith & Downs (1977: 668) by having elongated stamens and pistil equaling the claw of the petals and plicate filaments. By having the adaxial sepals carinate and distinctly connate, the species proposed here belongs to the T. tenuifolia complex sensu Tardivo (2002: 118) .

The new species is morphological closely related to T. toropiensis , which is endemic of the central region of the state of Rio Grande do Sul, growing saxicolous associated to the Cactaceae with Eriocactus magnificus Ritter (1966a: 50) , on steep rocks along the Toropi River ( Rauh 1984). Tillandsia leucopetala differs from T. toropiensis by its larger size (flowering up to 45 cm long vs. up to 30 cm long), longer leaf blades (12–30 cm vs. 8–20 cm), longer peduncle (12–30 cm vs. 8–19 cm), longer inflorescence (4.3–11 cm vs. 2.5–5.5 cm), with comparatively more flowers (4–11 vs. 3–7), as well as longer sepals (1.8–2.6 cm vs. 1.7–2 cm) and longer petals (up to 4 cm vs. up to 3.4 cm). Tillandsia leucopetala also differs by the color of the usually yellowish-green peduncle bracts and floral bract (vs. reddish), and by the lepidote sepals (vs. glabrous), having the adaxial ones connate up to the middle portion (vs. almost completely connate).

Tillandsia leucopetala has some morphological affinity with Tillandsia nuptialis Braga & Sucre (1969: 1) , an endemic species from Rio de Janeiro, Brazil. However, it can be distinguished by its shorter stem, longer leaf blades (12–30 cm vs. 9–11 cm long), usually longer peduncle (up to 30 cm vs. up to 14 cm), longer inflorescence (up to 11 cm vs. up to 7 cm) with more flowers (to 11-flowered vs. ca. 6-flowered), floral bracts densely lepidote throughout the abaxial surface (vs. lepidote at the apex only), longer petals (up to 4 cm vs. up to 3 cm) and longer sepals (up to 2.6 cm vs. up to 2.1 cm).

Figures

FIGURE 1. A–H. Tillandsia leucopetala (H. Büneker et al. 249). A. Habit. B. Abaxial side of scape bract. C. Abaxial side of floral bract. D. Abaxial side of connate and carenate adaxial sepals. E. Abaxial side of abaxial sepal. F. Petal. G. Stamen. H. Pistil.

FIGURE 2. A–C. Tillandsia leucopetala (H. Büneker et al. 249). A. General view of the type locality. B. Population at the type locality in flowering, together with Eriocactus claviceps. C. Habit.