Bulbostylis cangae C.S.Nunes & A.Gil, 2017

Viana, Clebiana De Sá Nunes Nara Furtado De Oliveira Mota Pedro Lage & Gil, André Dos Santos Bragança, 2017, Bulbostylis cangae, a new species of Cyperaceae from Northern Brazil (Serra dos Carajás, Pará State), Phytotaxa 299 (1), pp. 96-102 : 97-99

Bulbostylis cangae C.S.Nunes & A.Gil , sp. nov. ( Figs. 1 , 2 , and 3A)

Type:— BRAZIL. Pará: N1, margens do lago natural, arredores dos alojamentos DOCEGEO, 30 October 1985, fl., fr., R. Secco & O. Cardoso 677 (holotype: MG!, isotype: SPF)

Perennial, caespitose herb, 11–48 cm tall, roots thick, caudex 2.5–3 × 1.5–2 cm, castaneus to ferrugineus. Culms 10–41 × 0.3–0.4 mm, terete, longitudinally ribbed, dark green to castaneous, antrorselly scabrous toward the apex, glabrous toward the base. Leaves ca. 4.5–30 × 0.05 cm; blades setaceous, recurved, margins antrorsely scabrous, apex acute, adaxial surface convex, canaliculated, antrorsely scabrous at long of the midrib, abaxial surface concave, smooth; sheaths 0.9–1.6 cm long, papyraceous, glabrous, adaxial side longitudinally canaliculated, apex acute, margins hyaline, densely hirsute with castaneous trichomes 3–4 mm long. Involucral bracts ca. 4, 4–9.3 × 2.2–4 mm, pale brown, glume-like, widened at the base, surface puberulent, apex long-apiculate; lower bract 6–9 mm long, slightly overtopping the inflorescence, the others gradually smaller, hyaline, margins ciliate, trichomes 0.3–0.8 mm long. Inflorescence 7–9 × 8–10 mm, capitate, with 5–6 sessile spikelets; spikelets 4–7 × 2–3 mm, ovoid, apex acute, flowers 11–14; glumes persistent, ca. 3–4 × 1.5 mm, ovate to lanceolate, castaneous with a prominent pale brown midrib, membranaceous, glabrous, apex acute, margins lacerate, ciliate. Stamens 3, anthers 0.3–0.4 mm long, linear, with a short apicule at apex; style trifid, ca. 0.5 mm long, slightly fimbriate. Achene ca. 1 × 1 mm, trigonous, obovoid, surface transverselly rugose, slightly stipitate, pale brown, shiny; stylopodium persistent discoid, dark brown, apex obtuse.

Distribution and Habitat: — Bulbostylis cangae is endemic to the cangas of the Serra dos Carajás (Pará State), with herbarium records in the municipalities of Parauapebas—Serra Norte (N1 plateau)—and Canaã dos Carajás— Serra Sul (S11A) and Serra do Tarzan ( Fig. 2 ). All the specimens collected in the Serra Norte (N1 plateau) are from the late 1970’s, and the species was never found again in this plateau, pointing to a possible decline in population size of this area. The landscape in the Serra Norte has clearly changed over time, due to its long history of human occupation, with more than 50 years of iron ore extraction activity and anthropization, resulting in diferent issues, such as the entry of several invasive species. The new species co-occurs with other Cyperaceae species like Bulbostylis conifera ( Kunth 1837: 206) C.B. Clarke (1990: 86) , Fimbristylis miliacea (L. 1759: 868) Vahl (1805: 287), Rhynchospora barbata ( Vahl 1798: 4) Kunth (1837: 290) ( Nunes et al. 2016a) and species of other families such as Poaceae Barnhart , Polygalaceae Hoffmanns. & Link , Orchidaceae Juss. It is found on the tops of mountains of Carajás region, growing inside of the clefts in the cangas and part of its caudex is completely “embedded” in these clefts ( Fig. 3 B, C and D ). All fertile specimens examined were collected in October, the dry season in the region.

Conservation Status: — Bulbostylis cangae should be classified according to the criteria of the IUCN RedList ( IUCN 2014) as Endangered [B1 ab (ii,iii), B2 ab (ii, iii)]. This species is known so far only from the region of Serra dos Carajás, with an estimated extent of occurrence of 616 km ², area of occupancy of 48 km ², known only from three locations and a projected decline of its area o occupancy and quality of habitat due to mining plans in the region.

Etymology: —The specific epithet cangae refers to the vegetation on ironstone outcrops (canga) of Serra dos Carajás, where the species was found.

Taxonomic relationships: — Bulbostylis cangae is characterized by the presence of a caudex, fimbriate sheaths apex, stramineous trichomes, glume-like involucral bracts, 5–6 spikelets per head, obovoid achene, with transversely rough surface and discoid stylopodium. Bulbostylis cangae is similar to Bulbostylis medusae Prata, Reynders & Goetghebeur ( Prata et al. 2007: 67) that occurs in Venezuela, in the Amazon region, for presenting capitate inflorescence, ovoid spikelets, brown ovate glumes. It also resembles Bulbostylis sellowiana ( Kunth 1837: 208) Palla (1908: 179) , a species that occurs only from Northeast to the South Brazil, by its habitat and structure of the inflorescence.

Bulbostylis cangae differs from B. medusae by castaneous sheath apex (vs. white), inflorescence 0.7–0.9 cm long (vs. 1–1.5 cm), spikelets 4–7 mm long (vs. 10–15 mm), with a glabrous base (vs. white trichomes), glumes membranaceous (vs. papyraceous), obovoid achene (vs. cordiform) and discoid persistent stylopodium (vs. deciduous pyramidal). Bulbostylis sellowiana differs from B. cangae by absent caudex, red shealth apex, 2–4 spikelets in the inflorescence (vs. 5–6), coriaceous glumes, obcordiform achene, stylopodium deciduous (see comparison in Table 1).

Additional specimens examined (paratypes):— BRAZIL: Pará: Canaã dos Carajás, Serra dos Carajás, Serra Sul , Corpo A, 6°23’33” S, 50°22’22” W, 12 October 2008, fl., L.V. Costa, M. Sobral, C. Trancoso, L. Garcia & G. Maciel 597 (BHCB!) ; Serra do Tarzan , 14 October 2008, fl., L.V. Costa, M. Sobral, C. Trancoso, L. Garcia & G. Maciel 639 (BHCB!) ; Parauapebas, Serra Norte, near AMZA Exploration Camp , 6° S, 50°15’ W, 11 October 1977, fl., C.C. Berg & A.J. Henderson 463 (MG!, RB!) .

Figures

FIGURE 1. Bulbostylis cangae. A. Habit. B. Culm detail. C. Sheath apex. D. Abaxial surface of leaf blade. E. Adaxial surface of leaf blade. F. Lower involucral bract. G. Upper involucral bract. H. Inflorescence. I. Spikelets. J–K. Glumes. L. Achene. Illustration by João Silveira based on the holotype R. Secco & O. Cardoso 677 (MG).

FIGURE 2. Distribution map of Bulbostylis cangae in cangas of Serra dos Carajás. The light grey area represents the Carajás National Forest (FLONA Carajás); red circles, collection sites; black patches, canga plateaus; dark grey, mining pit.

FIGURE 3. Bulbostylis cangae. A. Caudex in detail. B–C. Clefts in the cangas where part of its caudex is completely “embedded”. D. Natural habitat, known locally as canga. (Photos by André Gil).