Alcantarea turgida

Alcantarea turgida Versieux & Wand., sp. nov. Brittonia 59(1): 57-64. 2007.
Alcantarea extensa (L.B. Sm.) J.R. Grant et a A. vinicolor (E. Pereira & Reitz) J.R. Grant affinis, sed plantis altioribus, inflorescentiis congestioribus, bracteis florum, sepalis, petalis et appendicibus petalorum majoribus differt.
Alcantarea imperialis (Carriere) Harms similis, sed vaginis et laminis foliorum angustioribus, bracteis primariis quam pedunculis valde minoribus, alabastris imbricatis, turgidis, nec complanatis differt.

Plant saxicolous, short caulescent, flowering up to 2.5 m high; rosette (0.7-)1.3-1.7 m diam., crateriform.
Leaves numerous, spreading, arcuate.
Sheaths broadly ovate 1927 x 8-19 cm, pale brown adaxially, dark brown becoming pale brown with dark wine-red color inclined lines at the top abaxially, densely brown lepidote on both surfaces.
Blades linear, long-attenuate, 61-75 x 7.5-11 cm, green, lustrous, inconspicuously dark wine-red along the margins, wine-colored spotted on both sides or only abaxially, lepidote on both sides but glabrescent toward the apex adaxially, coriaceous, distinctly nerved with some prominent longitudinal veins; blade apex acute to cuspidate, totally green or dark wine-red colored, recurved, apiculus twisted.
Scape erect, stout, 2-4 cm diam., 0.8-1.2m long, with internodes of 3.5-6.5 cm long, green underneath the bracts, wine-colored maculate on sun exposed portions, glabrous or nearly so.
Scape Bracts the proximal ones subfoliaceous and suberect, the distal ones spreading, recurved toward apex, broadly lanceolate, with an ovate base and a caudate and a dark wine-colored mucronate apex, completely green maculate with red or totally red at the base and green maculate with wine-red toward apex, brown lepidote, involute, distinctly nerved.
Inflorescence once branched, pyramidal to elliptic in outline, 0.6-1.3 x 0.7-1 m, main axis with 4-9 cm long internodes.
Flowering Branches subdensely arranged, 14-32 in number, (3-) 10-18-flowered.
Peduncle arcuate, the mid portion patent, and the terminal portion slightly erect or the entire branch weakly arcuate.
Rachis geniculate, 18-27cm long, 4 mm diam., olive-green toward apex, glabrous, with 3.5 (proximal) to 1 cm (distal) long internodes separating the flowers.
Primary Bracts broadly ovate, 6-9 x 6 cm at the base, with a 2-6 x 0.6 cm narrowly triangular and caudate apex, apex with a prominent vein and a recurved and rigid apiculus, shorter than the peduncles, green at the central portion and wine-colored along the margins and at the top or totally wine-colored, brown lepidote, involute, spreading, coriaceous, distinctly nerved.
Peduncles cylindrical to slightly flattened, 9-22 cm long, 6-7 mm diam. at the base, glabrescent, bearing 1-3 sterile bracts.
Sterile Bracts suborbicular, apex obtuse, discretely mucronate, 3-3.7 x 3-3.2 cm, glabrous abaxially, brown lepidote adaxially, involute, erect, symmetric or nearly so, coriaceous, distinctly nerved, carinate toward apex.
Floral Bracts convex, suborbicular, apex obtuse, discretely mucronate, 3.4-3.7 x 3.6-4(-4.4) cm, glabrous and lustrous abaxially, brown lepidote adaxially, green at the central portion and winecolored along the margins, membranaceous and pale yellow along the margins and coriaceous at the central portion on the dried material, distinctly rugose-nervate, carinate, inflated and densely imbricate at the branches apical portions.
Pedicels obconic, 8-11 mm long, ca. 4 mm diam..
Flowers odorless, not secund.
Sepals obovate, apex acute and minutely apiculate, 3.6-4(-4.4) x 1.4-1.8 cm, exceeding the floral bracts for ca. 1 cm, free, sparsely brown lepidote adaxially, green with membranaceous hyaline margins, ecarinate.
Petals long-linear with an acute apex, yellow in flower buds and immediately after the anthesis, fading quickly to creamy white, spreading, weakly twisted, 9.3-11 x 11.2 cm, free, glabrous, inconspicuously white spotted, margins entire with the distal -portion slightly undulate.
Petal Appendages 2, ligulate, 3.4-3.7 x ca. 0.3 cm, longitudinally adnate to the petal for 2.9-3.1 cm, the apex free, apices overlapping and completely hiding the ovary from a top view
Stamens free.
Filaments terete, 9-l0cm long, ca. 2mm thick, white.
Anthers sagittate, 1.2-1.6 cm long, ca. 1 mm thick, dorsifixed near the base, rimose.
Style terete, white, 9.3-l0cm long ca. 2 mm diam.
Stigma lobes white, ca. 4 x 1 mm, spreading.
Ovary ca. 22 x 6 mm, narrowly ovate, hypanthium ca. 8mm in length.
Ovules numerous, ca. 1.6 mm long, with an elliptic apical appendage, restricted to the upper 1/2 portion of the ovary.
Fruit an ellipsoid, rugose, dark castaneous, 5.3-6.2 cm long capsule.
Seeds narrowly elliptic, brown, ca. 6 x 1 mm.
Seed appendages fimbriate, the apical ones pale brown, ca. 15mm long, the basal ones whitish, ca. 7mm long.

Type: Brazil. Minas Gerais: Conceicao do Mato Dentro, alto da cachoeira do Tabuleiro, 1908'58.7"S, 4333'05.3"W 1300m, 22 Dec 2005, Versieux et al. 260 (holotype: SP; isotypes: BHCB, MBM, RB, SEL, SPF, VIC). (Figs. l, 2)

Distribution and ecology.
Alcantarea turgida grows as a heliophyte or semisciophyte on rocky outcrops in the southern portion of the Espinhaco range, Rio Doce drainage basin, state of Minas Gerais, in southeastern Brazil. It was observed occurring in semi-deciduous montane forest and in campo rupestre (i.e., grassland on rocky soils) vegetation of the Cipo range, usually above 1000m elevation. Its flowers are frequently visited by hummingbirds, especially by Phaethornis pretrei. Bees are also common visitors, perforating the petals to pillage pollen grains. Based on the, IUCN criteria (IUCN, 2001), A. turgida can be considered "Near Threatened" (NT). Regardless of its occurrence within three different protected areas, the common fires in adjacent grazing areas as well as the collection pressure for the ornamental trade constitute real threats for this species in the near future.

Phenology. Flowering individuals were observed in June and from December to February. Fruiting in April.

Etymology. The specific epithet is an allusion to the floral bracts that are densely imbricate and turgid, and completely filled with copious transparent viscose nectar that drips from the apex of the flowering branches.

Additional specimen examined. BRAZIL, Minas Gerais: Sao Goncalo do Rio Abaixo, Estacao Ecologica de Peti - Cemig, Mirante do Cruzeiro, 23 Apr 2002, Lombardi et al. 4748 (BHCB, RFA); Itabira do Campo, Jun 1902, Mello-Martos s.n. (R 46318); Santana do Riacho. Parque Nacional da Serra do Cipo, 1913'23.4"S, 4330'06.6"W 1200m, 11 Dec 2005, Wanderley et al. 2488 (SP).

Alcantarea turgida is vegetatively similar to A. extensa (L. B. Sm.) J. R. Grant and to A. vinicolor (E. Pereira) J. R. Grant. In comparison to the latter two species, A. turgida has a different type of inflorescence, with the main axis almost straight (vs. slightly geniculate), the flowering branches more numerous, shorter (also more densely arranged), and patent and ascending toward the apex or weakly arcuate (vs. lax inflorescences with long and spreading flowering branches). Alcantarea turgida also has longer sepals, petals, and petal appendages. Also, in the dried specimens of A. turgida, the floral bracts are not as dark as in A. extensa.
Alcantarea turgida also resembles A. imperialis (Carriere) Harms, but it can be separated from the latter by the length of the primary bracts, which are shorter than the peduncles, by the inflated floral bracts and floral buds at the apex of the branches (vs. totally flattened floral buds), by the lustrous foliage (vs. glaucous), by the flowers not secund (vs. secund), and by the form of the flowering branches, which are patent and ascending toward the apex or weakly arcuate (vs. pendulous, and with a sigmoid shape).
It is also important to distinguish A. turgida from A. geniculata (Wawra) JR. Grant, since Smith and Downs (1977) cited the collection Mello-Mattos s.n. (R) from Itabira do Campo, Minas Gerais - treated here as additional material of A. turgida - as Vriesea geniculata (Wawra) Wawra [basionym of Alcantarea geniculata (Wawra) J.R. Grant]. In contrast to A. turgida, A. geniculata is an endemic species of Rio de Janeiro that occurs mainly at serra dos Orgaos (Leme, 1997), and has smaller sepals, peduncles, and petal appendages; also, the primary bracts equal or surpass the sterile base of the branches, the inflorescence is more densely arranged, and the foliage is completely green while it is wine-colored spotted abaxially and may be totally wine-red colored on the distal adaxial surface in A. turgida.

Updated 26/11/07