Paspalum imbricatum Filgueiras (1981: 153)

Delfini, Carolina, Souza, Vinicius Castro & Zuloaga, Fernando Omar, 2017, Taxonomic revision and nomenclatural update of Paspalum sect. Pectinata (Poaceae, Panicoideae, Paspaleae), Phytotaxa 323 (1), pp. 1-26 : 12

4. Paspalum imbricatum Filgueiras (1981: 153) . Fig. 1O–R

Type:— BRAZIL. Mato Grosso do Sul: Sidrolândia, Rodovia BR 163, orla de brejo, 27 October 1970, G. Hatschbach 25281 (holotype US 2705820!, isotypes K 643577!, MBM 16357!, MO 210263!, NY 864716!, UEC 16969!).

Caespitose perennial, robust, 60–150 cm tall. Culms erect, compressed, nodes glabrous to pilose, generally with imbricate, arched, thick and rigid rhizomes, rhizomes pale yellow; aestivation convolute. Sheaths usually longer than the internodes, predominantly disposed at the apex of the culms, hirsute mainly at the basal and apical portions, with hyaline trichomes, 1–2 mm long. Ligules 1.5–1.7 mm long, narrowly ovate, membranous, brown, the margins dentate to serrate. Blades 30–60 × 0.5–1.3 cm, linear, flat, hirsute; the apex acuminate, the margins entire to undulated, papillose-ciliate, hyaline cilia, 2–6 mm long; nerves conspicuous; adaxial and abaxial surfaces hirsute, with simple and hyaline papillose-trichomes, 1–2 mm long. Inflorescences 9–20 cm long, 5–13 racemes, racemes 9–18 cm long, subdigitate, axillary inflorescences absent; peduncle 25–45 cm long, glabrous. Rachis (1.8–) 2–2.9 mm wide, ending in a naked point, linear to slightly sinuous, glabrous, apical spikelet absent. Spikelets 4.8–6.7 × 2.5–3.5 mm, solitary, arranged into two series along the rachis, pedicellate, pedicels glabrous; lower anthecium ca. 2 mm larger than the upper anthecium; upper glume pale yellow, ovate, widely winged, 5-nerved, the nerves conspicuous, midnerve present, the apex acute to obtuse, the margins ciliate, hyaline cilia, 0.2–0.3 mm long, the base cordate, the surface glabrous to scabrous; lower lemma subequal or slightly smaller than the upper glume, pale yellow, ovate to lanceolate, widely winged, 5-nerved, the nerves conspicuous, midnerve present, the apex acute, the margins ciliate, hyaline cilia, 0.2–0.3 mm long, the base cordate, the surface delicately pilose between the nerves, hyaline trichomes, 0.5–1.5 mm long; upper anthecium 3.7–4 × 1.1–1.3 mm, pale yellow, sessile, ovate to lanceolate, with a tuft of tiny trichomes at the apex of the upper lemma; upper lemma and upper palea minutely papillose, the midnerve absent, the apex acute to obtuse. Anthers 1.9–2.2 mm long, orange. Styles 2, stigmas plumose, orange. Lodicules 2. Caryopsis ca. 1 mm long, obovate, brown.

Distribution and habitat: —Distributed in Brazil, in states of Espírito Santo (first record) Goiás, Mato Grosso, Mato Grosso do Sul and Distrito Federal ( Fig. 3 ). Paspalum imbricatum is commonly found in sandy, rocky or waterlogged soils of fields, and savannas and campos rupestres, between 800 and 1250 meters.

Comments: — Paspalum imbricatum is characterized by sheaths and blades hirsute, the upper glume glabrous, the lower lemma slightly pilose between nerves, and both the upper glume and lower lemma 5-nerved and winged. This species is morphologically similar to P. aspidiotes , which is distinguished mainly by the shape of blades (linear in P. imbricatum vs. lanceolate in P. aspidiotes ) and by the width of rachis (2–2.9 mm vs. 2.9–4.5 mm wide). Denham et al. (2002) also separated these two species by the indumentum of the upper glume and the lower lemma, which is glabrous in P. imbricatum and hairy in P. aspidiotes . However, considering that the spikelets of P. aspidiotes range from glabrous to pilose, the above-mentioned characters do not distinguish P. imbricatum from P. aspidiotes .

Paspalum imbricatum also shares morphological similarities with P. lanciflorum , but it is easily distinguished from that species by the upper glume, which is 5-nerved and glabrous in the former species and 3-nerved and pilose at the base in the latter species.

Specimens examined: — BRAZIL. Distrito Federal: Brasília, Reserva Ecológica do IBGE, brejo na nascente do córrego escondido, na borda do brejo, 14 June 1988, D. Alvarenga 63 (CEN, SP, UEC); Córrego Mata Gado, crescendo em brejo junto ao lago Paranoá, 20 March 1982, T.S. Filgueiras 970 (IBGE, RB); Lago Paranoá, confluência do córrego Cabeça do Vento, brejo, 23 March 1982, E.P. Heringer 7382 ( US); Ca. 25 km SW of Brasília, creek margin near waterfalll, 950 m, 10 February 1966, H.S. Irwin 13034 et al. (NY, US); Reserva Ecológica do IBGE, 14 February 1985, R.C. Mendonça 443 (MAC); Parque Nacional de Brasília, vereda, solo saturado escuro, 1095 m, 10 February 2011, R.C. Oliveira 2564 et al. (UB); ARIE Santuário de Vida Silvestre do Riacho Fundo, próxima à mata ciliar, campo murundu, 6 March 1998, R.R. Silva 36 (UB); Brejo próximo ao córrego da Papuda, s.d., T.S. Filgueiras 1313 (CEN); Área de brejo próximo ao CNPH da EMBRAPA, 10 February 1996, T.S. Filgueiras 3371 ( US); Córrego Mata Gado, 20 March 1982, T.S. Filgueiras 969 (INPA); APA Gama-Cabeça de Veado, Cristo Redentor, brejo,1992, T.S. Filgueiras 2131& F.O. Zuloaga (MO). Espírito Santo: Rio Bananal, without additional data, March 1895, A.F.M. Glaziou 22544 et al. ( US). Goiás: Cristalina, Serra dos Cristais, ca 3 km N of Cristalina, 1250 m, 2 March 1966, H.S. Irwin, 13241 (MO, NY, US). Formosa, BR 040, km 47 BsB– Formosa, s.d., A.C. Allem 2624 (CEN). Mineiros, Parque Nacional das Emas, Água Ruim road, southeast area of the park, brejo with sand road around it, 22 March 1994, T.S. Filgueiras 2875 (IBGE). Pirenópolis, Serra dos Pireneus, na base dos três picos, mata ciliar de campo rupestre, 5 May 1971, J.A. Rizzo 6301 (ICN). Posse, Serra Geral de Goiás, rio da Prata, ca. 6 km of Posse, 4 April 1966, H.S. Irwin 14507 (NY); A 3 km da cidade de Posse pela BR 20, campo rupestre, solo arenoso, 20 May 1983, J.A. Rizzo 10289 (MO, UFG). Mato Grosso: Santa Cruz do Xingu, Parque Estadual do Xingu, limite norte do Parque, campo rupestre da Amazônia sobre rochas de arenito, em pequena cachoeira, 277 m. s.m., 10 March 2011, C.R.A. Soares 3204 et al. (CEN, K, RB, SP); Parque Estadual do Xingu, limite nordeste do Parque, subindo o rio Fontourinha, campo rupestre da Amazônia , sobre rochas graníticas com Vellozia seubertiana , Kielmeyera e Agonandra , 280 m. s.m., 1 March 2011, W. Milliken 4200 et al. (CEN, K, RB, SP). Mato Grosso do Sul: Campo Grande, APA do Guariroba, borda de vereda parcialmete conservada, solo arenoso, fundo de vale, 10 December 2006, G.A. Damasceno-Junior 4483 (CGMS). Sidrolândia, rodovia BR 163, orla de brejo, 27 October 1970, G. Hatschbach 25281 (MBM, MO).

Figures

FIGURE 1. A–D: Paspalum aspidiotes: A. Upper glume; B. Spikelet, view of the lower lemma; C. Upper lemma; D. Upper palea. E–J: Paspalum cachimboense: E. Habit; F. Node detail; G. Spikelet, view of the upper glume; H. Lower lemma; I. Upper anthecium, view of the upper lemma; J. Upper palea. K–N: Paspalum cordatum: K. Upper glume; L. Lower lemma; M. Upper lemma; N. Upper palea. O–R: Paspalum imbricatum: O. Upper glume; P. Spikelet, view of the lower lemma; Q. Upper lemma; R. Upper palea. S–V: Paspalum lanciflorum: S. Spikelet, view of the upper glume; T. Lower lemma; U. Upper lemma; V. Upper palea. W–Z: Paspalum pectinatum: W. Upper glume; X. Spikelet, view of the lower lemma; Y.Upper lemma; Z. Upper palea. A’–D’: Paspalum reticulinerve: A’. Upper glume; B’. Spikelet, view of the lower lemma; C’. Upper lemma; D’. Upper palea. [A–D: N.A. Rosa 2369 (INPA); E–J: M.N. Silva 24 et al. (RB); K–N: H.M. Longhi-Wagner 8963 et al. (ICN); O–R: T.S. Filgueiras 970 (IBGE); S–V: A. Chase 11402 (RB); W–Z: A. Rizzo 4470 (RB); A’–D’: T. Killeen 4824 et al. (SI)]. Drawn by Maíra Mezzacappa.

FIGURE 3. Distribution map of Paspalum cachimboense and P. imbricatum.