Cyperus potiguar A.R.O.Ribeiro, M.Alves & R.C.Oliveira, 2015

Ribeiro, André Rodolfo De Oliveira, Alves, Marccus & Oliveira, Regina Célia De, 2015, A new species of Cyperus L. (Cyperaceae) from northeastern Brazil, Phytotaxa 204 (2), pp. 153-158 : 154

Cyperus potiguar A.R.O.Ribeiro, M.Alves & R.C.Oliveira , sp. nov., Figs. 1–2

Herba caespitosa , perennis ; rhizoma incrassatum; culmi 74 ad 93 cm alti, trigoni, papillosi, glabri; folia 4 ad 9 mm lata, chartacea, papillosa, glauca; bracteae inflorescentiae 8 vel 9; spiculae 8–67, deciduae; internodia rachilae 0,9–1,2 mm longa; glumae (5–)7–11, persistentes, 2,7–3,0 mm longae, 1,4–1,6 mm latae; stamina 3; stigmata 3; achenium trigonum, obovoideum vel ovoideum. Affinis Cypero ligulari L. et C. alvesii G.C. Tucker , sed differt ab ambobus glumis plurioriobus, longitudinibus glumarum et internodiorum rachilae mediocribus; a C. alvesii latitudine glumarum majore (in C. ligulari aequiparabili ).

Type: — BRAZIL: Rio Grande do Norte State: Jucurutu, Serra João do Vale, 06º00’43”S, 37º08’52”W, 29 May 2010, fl. and fr., A. R. O. Ribeiro, M. L. Silva, A. S. Silva, C. C. P. Leal, S. H. Santana & J. E. Araújo 247 (holotype UB!, isotypes MOSS!, RB!).

Caespitose perennial herb, 90–114 cm tall. Rhizome pachymorph. Culm 74–93 cm x 3.9–4.5 mm, trigonous, papillose, glabrous, transverse septa absent. Leaf blade 6–53 cm × 4–9 mm, linear-triangular, conduplicate, chartaceous, glaucous, papillose on abaxial surface, smooth, rarely papillose on adaxial surface, antrorsely scabrous on margins and midrib on abaxial surface, apex acuminate; leaf sheath 6–25 cm long, membranous to cartilaginous, glabrous. Inflorescence bracts 8–9, 2.3–75.5 cm × 1.3–11.0 mm. Inflorescence 18–20 × 21–24 cm; 2–3 orders of branches, anthelodium on first order, anthelodium or spike on second order, spike on ultimate order. Primary rays 11–12, 2.7–16.0 cm long, subtended by a sheathing prophyll. Secondary bracts 1.8–13.0 × 0.4–1.3 mm. Secondary rays absent or present, up to 8, 5–23 mm long. Spikes 1.3–2.3 × 1.2–2.2 cm, hemispheroid to widely oblong. Rachis 3–9 mm long, visible or hidden by spikelets. Spikelet bract 0.8–1.4 × 0.5–0.8 mm, apex acute to rounded, muticous. Spikelet prophyll 1.4–1.7 × 0.9– 1.1 mm, apex obtuse to rounded. Spikelets 8–67 per spike, 6–14 × 1.0– 1.8 mm, 0.6–0.8 mm thick, lanceolate laterally compressed, ratio wide: thick 1.4–2.3: 1. Rachilla articulate at base, internodes 0.9–1.2 mm long; rachilla wing 0.4–0.6 mm wide, membranous, hyaline to hyaline-greenish. Glumes (5–)7–11, 2.7–3.0 × 1.4–1.6 mm, persistent, appressed, ovate, glabrous, one-keeled, 9–11- nerved (including keel), apex obtuse to rounded, muticous or mucronate, margins vinaceous to brownish, keel greenish, mucron up to 0.1(–0.2) mm long, straight. Stamens 3; anther 0.5–0.7 × 0.10– 0.15 mm, yellow, connective not prolonged or up to 0.1 mm long, reddish to reddish-brown, glabrous. Style 0.3–0.6 mm long; stigmas 3, 1.5–1.8 mm long. Achene 1.4–1.6 × 0.6–0.7 mm, obovoid to ovoid, apex acute and mucronulate, brownish to brownish-orange, surface papillose, completely covered by glume.

Distribution:—At present, it is known only from Caatinga semi-arid vegetation in the Rio Grande do Norte State, northeastern Brazil ( Fig. 3 ). According criteria proposed by IUCN (2014), C. potiguar has status of “Endangered”, because its geographic range is restricted to less than five locations.

Phenology:— Collections were made in May and August.

Etymology:—The specific epithet potiguar means “of or relating to the state of Rio Grande do Norte ”. The word potiguar is often used to designate the natives from this Brazilian state, and it comes originally from the name of the indigenous tribe that lived in this state before the Portuguese colonization.

Morphological related species:— Cyperus potiguar is morphologically similar to C. ligularis L. and C. alvesii G. C. Tucker from which it differs by spikelets 6–14 mm long with rachilla internodes 0.9–1.2 mm long, and (5–)7–11 glumes with 2.7–3.0 x 1.4–1.6 mm. ( Table 1).

Additional collections (paratypes):— BRAZIL: Rio Grande do Norte State, Campo Redondo, Fazenda Giromão , 5 August 2009, fl., A. A. Roque 1051 ( UFRN) ; São Paulo do Potengi, logo após o trevo São Paulo do Potengi-Senador Elói de Souza , 14 May 2009, fl., R. C. Oliveira et al. 2381 ( MOSS) .

Figures

FIGURE 1. Cyperus potiguar A.R.O.Ribeiro, M.Alves & R.C.Oliveira, sp. nov. (A) habit; (B) detail of culm papillae; (C) detail of leaf margin (scabrous) and papillae on leaf abaxial surface; (D) inflorescence; (E) spike branch; (F) spikelet; (G) rachilla wings; (H) achene. Drawn by Darli Nuza from holotype in UB.

FIGURE 2. Photos of Cyperus potiguar, A.R.O.Ribeiro et al. 247 (holotype), taken in its natural habitat in the state of Rio Grande do Norte, 2010: (A) habit; (B) detail of culm papillae; (C) detail of papillae on leaf abaxial surface; (D) detail of leaf margin (antrorsely scabrous); (E) inflorescence; (F) detail of spike branch.

FIGURE 3. Distribution map of Cyperus potiguar in the Rio Grande do Norte State, Brazil.