Aechmea nigribracteata J.R. Maciel, Louzada & M. Alves, 2014

Maciel, Jefferson Rodrigues, Louzada, Rafael & Alves, Marccus, 2014, Aechmea nigribracteata (Bromeliaceae), a new species from southern Bahia, Brazil, Phytotaxa 188 (4), pp. 233-237 : 233-236

Aechmea nigribracteata J.R. Maciel, Louzada & M. Alves , sp. nov. ( Fig. 1–2 )

Aechmea nigribracteata is morphologically related to A. depressa as shown by huge rosettes with leaves of 150–230 cm long, but differs from that species by having its central axis elongated (vs. compressed), inflorescence 24–30 cm long (vs. 11–14 cm long), floral bracts blackish (vs. reddish), lanceolate (vs. oblong), wholly dentate (vs. serrate in apical portion only) and anthers narrowly bilobed at the base (vs. not bilobed).

Type:— BRAZIL. Bahia: Una, Entrada no Km 49 da BA-001, 15°13’19”S, 39°01’45”W, 31 May 2014 (fl., fr.), J . R . Maciel, L . Daneu, D. Cavalcanti & B . S . Amorim 1950 (holotype UFP!, isotype FR!) .

Plants terrestrial or epiphytic herbs, shortly caulescent, flowering 70–80 cm tall, forming a funnelform or crateriform rosette. Leaves 12–25 in number, green, rigid-coriaceous, 150–230 cm long; leaf sheaths 25–35 × 20–30 cm, oblong, ample, contrasting in colour of the leaf blades, pale to dark brown, stiff-coriaceous, densely lepidote on both surfaces, with sub-adpressed and hyaline trichomes, margins entire, membranaceous; leaf blades 125–200 × 10–15 cm, green with brown to black apex, linear oblong, erect, stiff-coriaceous, channelled, densely lepidote on both sides of subadpressed and hyaline trichomes, apex attenuate then acuminate, margins densely serrulate; prickles antrorse, green to pale brown, 4–7 mm long, subtriangular. Inflorescences simple, spicate, strobiliform; fertile part of the inflorescence 24–30 cm long, 25–26 cm diam., globose; central axis elongated, dilated, 8–12 cm wide; peduncle 35–60 cm long, 4.5–5 cm diam.; peduncle bracts 44–50 × 5–6.5 cm, erect, sparsely lepidote, imbricate, rigid-coriaceous, oblonglanceolate, green to castaneous nearly throughout, black at the base, margins serrulate, apex acuminate; floral bracts 6.3–7 × 1.1–1.3 cm, much exceeding the sepals, straight or nearly so, densely imbricate, stiff-coriaceous throughout when completely developed or membranaceous at the base during the first stage of development, slightly carinate, lanceolate, acute, navicular, abaxially glabrescent, blackish, the margins wholly dentate, prickles 2–2.5 mm long. Flowers 6–7 cm long, spreading, pedicels 3–5 mm long; sepals 28–35 × 6–8 mm, incurved, carinate, free, sparsely lepidote on both surfaces, castaneous at the base and green toward the apex, very narrowly triangular, chartaceous, asymmetric, margins entire, apex mucronate, spines 0.8–2 mm long; petals 33–35 × 3–5 mm, free, erect, spathulate, fleshy, green, apex acute, corolla tubular-erect; appendages 2, crenate-laciniate, inserted at the base. Stamens about equal the pistil, included; filaments straight, 18–20 mm long, free; anthers 10–12 mm long, sub-basifixed, narrowly bilobed at the base. Ovary 19–21 mm long, trigonous; epigynous tube 8–10 mm long. Style stout; stigma conduplicatespiral, lobes with lacerate margins. Fruits 6–8 cm long, cylindrical, green.

Etymology:—The name Aechmea nigribracteata refers to blackish floral bracts which also have dark dentate margins. This combination of character states is unique among Aechmea subg. Chevaliera species.

Distribution and habitat:— Aechmea nigribracteata is only known from a restricted area of Atlantic coastal forest (Una region) in southern Bahia state, northeastern Brazil. This is an area particularly diverse in bromeliads species ( Fontoura & Santos 2010), where five species of Aechmea subg. Chevaliera have been recorded ( Fontoura & Santos 2010, Leme 2010, Sousa 2004) and recently recollected. These species are Aechmea conifera Smith (1941: 53) , A. depressa Smith (1941: 54) , A. gustavoi Siqueira & Leme ( Leme & Siqueira-Filho 2001: 147) , A. multiflora Smith (1937: 4) and A. perforata Smith (1941: 55) . Aechmea nigribracteata grows as an epiphyte on the lower and stronger branches of trees or can be found as a terrestrial plant in sandy soils in coastal shrubby vegetation (locally called “Restinga”) where it forms dense clumps ( Fig. 2d ). The region has an average of 1,800 mm rainfall a year and the driest months are between December and March ( Fontoura & Santos 2010).

Phenology:— Aechmea nigribracteata was collected flowering and fruiting between May and July.

Conservation status:—The species is considered critically endangered based in criteria B1 (extent of occurrence less than 100 km ²) ( IUCN 2013).

Comments:—The strobiliform inflorescence, rigid floral bracts, and petals with ligules lead us to conclude that Aechmea nigribracteata belongs to Aechmea subg. Chevaliera ( Figs. 1–2 ). Within this subgnenus A. nigribracteata is related to the species of the A. multiflora complex ( Canela et al. 2003) and is morphologically close to Aechmea depressa due to its huge rosettes, with leaves of 150–230 cm long and leaf blades 10–15 cm wide. However A. nigibracteata differs from A. depressa by having its central axis elongated (vs. compressed), inflorescence 24–30 cm long (vs. 11–14 cm long), and floral bracts blackish (vs. reddish), lanceolate (vs. oblong), wholly dentate (vs. serrate in apical portion only) and anthers narrowly bilobed at the base (vs. not bilobed).

The morphological relationships of A. nigribracteata with other species from A. multiflora complex is expressed in the taxonomic key below.

Figures

FIGURE 1. A–I. Aechmea nigribracteata (J.R. Maciel et al. 1950). A. Habit, B. Leaf, C. Floral bract, D. Flower, E. Longitudinal view of flower, F. Sepal (adaxial view), G. Petal (abaxial view), H. Stamen, I. Stigma. (Drawn from the holotype by Regina Carvalho).

FIGURE 2. A–D. Aechmea nigribracteata (J.R. Maciel et al. 1950). A. Inflorescence, B. Longitudinal section of inflorescence, central axis and peduncle details, C. Floral bracts and flower details, D. Habit. (Photos: J.R. Maciel).