Orthophytum argentum Louzada & Wand., 2011

Louzada, Rafael Batista & Wanderley, Maria Das Graças Lapa, 2011, A new species of Orthophytum (Bromeliaceae) from Chapada Diamantina, Bahia, Brazil, Phytotaxa 28, pp. 27-30 : 27-29

Orthophytum argentum Louzada & Wand. , sp. nov., Fig. 1 A–I

Type:— BRAZIL. Bahia: Rio de Contas, Fazenda Vacaro , Caminho para o Morro da Teta , 13 o 32’50”S, 41 o 52’24.2”W, 1,250 m, 12 February 2009, R. B . Louzada , M. G. L . Wanderley & A. M . Benko-Iseppon 110 (holotype SP, isotype HUEFS) .

Orthophytum argentum O. toscanoi Leme simile, sed bracteis floralibus et sapalis atrovinaceis, aculeis laminarum glabris, haud ad basim intumescentibus differt.

Plant rupicolous, short caulescent. 24–34 cm tall, forming an open rosette. Rhizomes short, stems wholly covered by leaves. Leaf sheaths distinguishable from the blades, chartaceous, ovate, castaneous, margins serrulate, glabrous on both sides. Leaf blades homomorphic, 15–20 × 2.0– 2.5 cm at the base, rigid, coriaceous, narrowly triangular, arching, channeled, cinereous, densely lepidote on both sides, margin densely serrate, prickles slender, dark brown, 3.5–4.0 mm long gradually shorter toward the apex, retrorse, apex long attenuate, pungent. Peduncle elongate, erect, 11–18 cm long, woolly lepidote, dark-vinaceous; peduncle bracts divergent, much exceeding the internodes, foliaceous, coriaceous, narrowly triangular, margins densely serrate and lepidote, apex long attenuate, pungent. Inflorescence ca. 12 cm long, double raceme, of 7–8 branches, lax, dense at apex; axis wholly exposed, slender, straight, terete, glabrescent, dark-vinaceous. Primary bracts foliaceous, patent or reflexed, gradually becoming smaller toward the apex, coriaceous, lineartriangular or ovate-lanceolate, margin serrate, the upper shorter than the branches, or the lower exceeding the branches, both surfaces subdensely lepidote, apex pungent. Floral bracts ca. 15 × 10 mm, clasping the flowers, coriaceous, surface prominently nerved, carinate, triangular, margins serrate or serrulate, about equaling the sepals, sparsely lepidote, dark-vinaceous, apex pungent. Flowers ca. 17 mm long, sessile. Sepals subcoriaceous, ca. 10 × 4 mm, triangular, asymmetric, margins entire, adaxial ones carinate, distinct from the ecarinate abaxial one, free, glabrous on both sides, dark-vinaceous, apex pungent. Petals ca. 13 mm long, elliptic, green with white blades, with two conspicuous callosities; blades ca. 5 mm wide, free from each other, apex spreading to recurving, obtuse; petal appendages fimbriate, well above the base. Stamens included, exceeding the pistil; first whorl of filaments (opposite to the sepals) free, the second whorl adnate to the petals, ca. 8 mm long; anthers 3–4 mm long, elliptic, dorsifixed nearly at the middle. Ovary trigonous, ca. 3 mm long, green. Epigynous tube absent. Ovules obtuse, not caudate; placentation axial. Stigmas simpleerect. Fruits and seeds not seen.

Distribution and habitat:— Orthophytum argentum is known from Rio de Contas municipality in Bahia. It grows on quartzite rock outcrops within campos rupestres as rupicolous, close to streams or in shaded habitats, more rarely in open places between 1,000 and 1,300 m elevation.

Comparison:— Orthophytum argentum is morphologically similar to O. toscanoi , but differs mainly in its conspicuous floral bracts and dark-vinaceous sepals. The prickles on the leaf margins are very slender, glabrous and dark-brown; the peduncle is dark-vinaceous and covered by a woolly indument. Orthophytum toscanoi has green floral bracts and sepals; the prickles on the leaf margins has a swollen base and are densely white-lepidote; the peduncle is greenish-bronze. Additionally O. argentum specimens always grow as rupicolous, while O. toscanoi specimens were found growing as terrestrials in wet forested places ( Leme 2003).

Etymology:— The name of the species was chosen due the silver-like gloss of the leaves, produced by an increased density of the scales.

Additional specimens examined:— BRAZIL. Bahia: Rio de Contas, Rio Brumado, estrada para a Cachoeira do Fraga , 22 September 1981, A . Furlan et al. CFCR 1705 ( RB, SPF); Cachoeira do Fraga , 900 m, 13 o 37’ S, 41 o 46’ W, 4 November 1988, R. M . Harley et al. 25912 ( CEPEC, MBM, SP, SPF); perto da Cachoeira do Fraga , 900 m, 21 May 1991, S. J . Mayo et al. 851 ( CEPEC, HB, MBM); Salto do Fraga , 1100 m, 6 April 1992, G . Hatschbach et al. 56709 ( MBM); 13 o 35’55” S, 41 o 49’45” W, 950 m, 2008, M . Machado 278 ( HUEFS) .

Figures

FIGURE. 1. A–I. Orthophytum argentum (from the holotype). A. Habit. B. Complete flower with floral bract. C. Floral bract. D. abaxial sepal. E. adaxial sepal. F. adaxial sepal with the opposite stamen. G. Petal with one adnate stamen, showing two petal callosities and two supra basal appendages. H. Flower section showing adaxial sepal with the opposite stamen, petal with the adnate stamen, petal callosities and appedages, and the gynoecium showing style, stigma and ovary with axial placentation. I. Detail of the stigma.