Alcantarea nana Leme, 2014

Leme, Elton M. C., Till, Walter, Kollmann, Ludovic J. C., De Moura, Ricardo L. & Ribeiro, Otávio B. C., 2014, Miscellaneous New Species of Brazilian Bromeliaceae, Phytotaxa 177 (2), pp. 61-100 : 72-75

Alcantarea nana Leme , sp. nov. ( Figs. 7 , 8 A–E )

This new species is closely related to Alcantarea simplicisticha , differing by the distinctly smaller size when flowering (50–100 cm vs. 200–240 cm), shorter leaf blades (19–25 cm vs. 35–40 cm), shorter peduncle (33–60 cm vs. 95–100 cm), all peduncle bracts exceeding the internodes (vs. the upper ones distinctly shorter than the internodes), shorter inflorescence (15–20 cm vs. 80–110 cm) with smaller number of flowers (10–18 vs. ca. 30), suborbiculate floral bracts (vs. elliptic to broadly ovate), which are shorter and broader (32–35 × 38–40 cm vs. 40–46 × 32–33 cm), rounded to slightly emarginate apex of the sepals (vs. subacute) and the appendages of the petals with truncate-emarginate apex (vs. acute to acuminate).

Type: –– BRAZIL. Minas Gerais: Alvarenga, Corrego Sujo, hill in front of Pico da Aliança , 1134 m elevation, 19º 23’ 27” S 41º 41’ 06” W, 23 June 2012, E . Leme 8677, R . Vasconcelos & R . Faria (holotype RB!) .

Plants rupicolous, stemless, flowering 50–100 cm high. Leaves 7–10 in number, rosulate, suberect, forming a narrow funnelform rosette; sheaths elliptic-ovate, 11–13 × 7.5–8.5 cm, coriaceous, subdensely and inconspicuously brown lepidote, abaxially castaneous toward the base and wine colored near the apex, adaxially green; blades linear or nearly so, not narrowed at the base, 19–25 × 5–6 cm, green or more often wine colored toward the apex, glabrescent, nerved, inconspicuously covered by a white wax, canaliculate mainly toward the base, suberect, apex recurved and subrounded to acute. Peduncle 33–60 cm long, 0.8–1 cm in diameter, erect, glabrous, green to wine colored; peduncle bracts exceeding the internodes, wine colored, covered by a white wax, with water-holding capacity, the basal ones shortly subfoliaceous, completely covering the peduncle, suberect with the apex slightly recurved, the upper ones nearly erect, broadly ovate, partially covering the peduncle, sulcate. Inflorescence simple, densely flowered, 15–20 cm long, 6.5–7.5 cm wide (excluding the petals), erect, inconspicuously covered by white wax (except for the petals); main axis stout, flexuous to geniculate, green to often wine colored, glabrous, covered by white wax, 0.4–0.7 cm in diameter, internodes 0.7–2.8 cm long; floral bracts suborbiculate, convex, 32–35 × 38–40 mm, apex obtuse, greenish at the base to completely wine colored, glabrous abaxially, inconspicuously brown lepidote adaxially, slightly shorter than the sepals, ecarinate. Flowers 10–18 in number, distichous, subspreading, not secund, not fragrant, ca. 14 cm long (with extended petal); pedicels ca. 12 × 10 mm, subcylindrical, green, glabrous, lustrous; sepals symmetric, narrowly elliptic, cymbiform, apex rounded to slightly emarginate, 37 × 16–17 mm, abaxially inconspicuously white lepidote, adaxially glabrous, free, coriaceous toward the base, ecarinate, green except for the wine colored apex; petals sublinear, apex attenuate, then narrowly obtuse-emarginate, ca. 13.3 × 1 cm, pale yellow to yellow-orange abaxially toward the apex due to the inconspicuous wine-colored spots, recurved at anthesis, completely exposing the stamens, becoming pendent-flaccidescent afterwards, at the base bearing 2 linear truncate-emarginate appendages of ca. 40 × 2.7 mm that are adnate to the petals for ca. 34 mm; stamens divergent, shorter than the petals; filaments terete, white, the antesepalous ones free, the antepetalous ones subfree; anthers linear, ca. 12 mm long, filiform at anthesis, dorsifixed near the base; style shorter than the petals, white; stigma conduplicate-spreading, blades slightly contorted, densely papillose, white, ca. 2 mm long. Capsules narrowly fusiform, long beaked, ca. 5 cm long, ca. 1.1 cm in diameter; seeds ca. 15 mm long (including appendages), the basal umbrella-like plumose micropylar coma 3–5 mm long, distinctly shorter than the straight undivided ca. 8 mm long apical chalazal appendage.

Distribution and habitat:–– Alcantarea nana is an exclusively rupicolous species living at the summit of the mountains in the county of Alvarenga, Minas Gerais state, ranging from 1000 to 1200 m elevation. It is an endemic species to the region of Alvarenga, living on rock outcrops in open areas covered by a peculiar intermediate type of Campos Rupestres vegetation, which is related to the Cerrado Biome and Campos de Altitude, which is related to the Atlantic Forest Biome. It was collected at two neighboring localities, where it forms small to medium-sized populations, which are composed of sparsely distributed, isolated to grouped individuals.

On the basis of the criteria “B1a” and “B2a” of IUCN (2010), A. nana must be considered a critically endangered species.

Etymology:–– The name of this new species is based on the Latin word nanus, meaning dwarf, which refers to dwarf stature of A. nana when compared to the remaining species of the A. extensa complex.

Additional specimen examined (paratype): –– BRAZIL. Minas Gerais: Alvarenga, near the border with Tarumirim, Córrego Alta Floresta , Serra do “Sibitiduca”, old property of Alcebíades , 1174 m elevation, 19º 24’ 37” S 41º 46’ 37” W, 22 June 2012, E . Leme 8668, R . Vasconcelos & R . Faria ( RB!) .

Observations:–– This new species is a member of the A. extensa complex. Versieux & Wanderley (2010) when trying to delimitate this complex of species, did not provide any alternative set of characteristics to be used to delimitate species of Alcantarea in general or specially those of the A. extensa complex, despite stating that the morphological characteristics usually used to segregate its species are highly influenced by environmental conditions especially when under cultivation and their utility to separate or describe new species is questionable. On the other hand, the molecular approach of Versieux et al. (2012a) segregated species from another that are obsviously morphologically related, and grouped together species distinctly separated by morphology and is not conclusive concerning infrageneric delimitation. This may explain why Versieux et al. (2012b), when describing a typical member of A. extensa complex, A. pataxoana Versieux ( Versieux et al. 2012b: 636) , based solely on a specimen which flowered in cultivation in Rio de Janeiro Botanical Garden and produced a malformed inflorescence clearly seen in the photographs illustrating the protologue, used traditional morphological traits to distinguish it from the closest relative, which is in direct conflict with previous statements (i.e., Versieux & Wanderley, 2010). Facing such a taxonomical incongruence, we continue to adopt here the available morphological criteria generally accepted during the past decades to distinguish species of Alcantarea .

Alcantarea nana is closely related to A. simplicisticha Leme & Fontana ( Leme et al. 2008: 209) , differing by the distinctly smaller size when in bloom (50–100 cm vs. 200–240 cm), shorter leaf blades (19–25 cm vs. 35–40 cm), shorter peduncle (33–60 cm vs. 95–100 cm), all peduncle bracts exceeding the internodes (vs. the upper ones distinctly shorter than the internodes), shorter inflorescence (15–20 cm vs. 80–110 cm) with smaller number of flowers (10–18 vs. ca. 30), suborbiculate floral bracts (vs. elliptic to broadly ovate), which are shorter and broader (32–35 × 38–40 cm vs. 40–46 × 32–33 cm), the sepals rounded to slightly emarginate at the apex (vs. subacute) and the petal appendages with a truncate-emarginate apex (vs. acute to acuminate).

Figures

FIGURE 7. Alcantarea nana (Leme 8677 et al.). A. Habit. B. Inflorescence. C. Details of the flower. D, E. Specimens in post-floral stage. F. Partial view of population with Rafael de Oliveira, highlighting the reduced size of adult plants.

FIGURE 8. A–E. Alcantarea nana (Leme 8677 et al.). A. Apex of the leaf. B. Floral bract. C. Floral bract and flower. D. Sepal. E. Petal with two basal appendages and a stamen. F–L. Alcantarea recurvifolia (Leme 8419 et al.). F. Apex of the leaf. G. Median-basal segment of the leaf blade. H. Basal floral bract. I. Apical floral bract. J. Flower. K. Petal with two basal appendages and a stamen. L. Sepal.