Paspalum reticulinerve Renvoize (1995: 339)

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 : 21

7. Paspalum reticulinerve Renvoize (1995: 339) . Fig. 1 A’–D’

Type:— BOLIVIA. La Paz: Prov. Iturralde, Siete Cielos, Río Manupare, ca. 2.5 km al E. Pampa con arbustos y árboles bajos (4–5 m) y torcidos, 12°27’S 67°37’W, 180 m, 8 June 1987, J.C. Solomon 17003 (holotype LPB 299!, isotypes BAA 2546! (fragment and photo ex LPB), K 643758!, MO 357721!).

Paspalum vallsii Oliveira & Rua (2005: 530) . Type:— BRAZIL. Goiás: Cavalcante, área de influência da UHE Cana Brava, Canteiro da obra, km 19, 13°27’08” S, 48°01’49” W, 350 m, 18 April 2002, G. Pereira-Silva 6438, G.A. Moreira & J.B. Pereira (holotype CEN 49819!, isotypes BAA 451!, ICN 146135!, K 643759!, MO 6182430!, NY 888056!), syn. nov.

Caespitose to shortly rhizomatous perennial, 60–120 cm tall. Culms erect, compressed, nodes glabrous; aestivation convolute. Sheaths usually longer than the internodes, disposed at the basal and apical portions of the culms, striated, glabrous to hirsute, with simple and hyaline papillose-trichomes, 1–5 mm long. Ligules 0.8–2 mm long, narrowly ovate to triangular, membranous, brown, the margins serrated. Blades 20–40 × 0.3–1 cm, frequently linear, sometimes lanceolate, flat, glabrous to hirsute, with long-trichomes (2.4–5 mm long) concentrated toward the basal portion; the apex acuminate, the margin frequently involute, ciliate, hyaline cilia 2–4.5 mm long, nerves conspicuous; adaxial and abaxial surfaces glabrous to hirsute, with simple and hyaline trichomes, 1–4.5 mm long. Inflorescences 2.5–12 cm long, (1–)2(–3) racemes, racemes 2.5–14 cm long, subdigitate, axillary inflorescences absent; peduncle 25–40 cm long, glabrous. Rachis (1.3–) 1.4–2.3 mm wide, ending in a naked point, linear to slightly sinuous, glabrous to slightly pilose, apical spikelet absent. Spikelets 4.2–6.7 × 3–4 mm, solitary, arranged into two series along the rachis, or less frequently paired, with the secondary spikelet rudimentary, pedicellate, pedicels glabrous to sparsely pilose; lower anthecium 2.6–3.2 mm larger than the upper anthecium; upper glume pale brown, widely ovate, widely winged, 5–7- nerved, the nerves conspicuous, midnerve present, the apex acute-ciliate, the margins ciliate, hyaline cilia, 0.2–0.4 mm long, the base cordate, the surface glabrous; lower lemma slightly smaller than the upper glume, pale brown, ovate, winged, 5-nerved, the nerves conspicuous, midnerve present, the apex acute, the margins ciliate, hyaline cilia, 0.2–0.4 mm long, the base cordate, surface glabrous; upper anthecium 2.9–4 × 0.9–1.2 mm, pale yellow, sessile, elliptic, with a conspicuous tuft of trichomes at the apex and margins of the upper lemma; upper lemma and upper palea minutely papillose, the midnerve absent, the apex acute. Anthers ca. 2 mm long, orange to purple. Styles 2, stigmas plumose, orange to purple. Lodicules 2. Caryopsis 1.5–2 mm long, obovate, brown.

Distribution and habitat: — Bolivia (La Paz and Santa Cruz) and Brazil (Pará, Tocantins, Goiás and Mato Grosso), between 100 and 900 meters ( Fig. 7 ). Paspalum reticulinerve grows predominantly in humid fields, savannas, campos rupestres, swamps, and less frequent in gallery forests.

Comments: — Paspalum reticulinerve is frequently confused with P. aspidiotes , but can be distinguished mainly by its rachis width (1.3–2.3 mm in P. reticulinerve vs. 2.9–5.5 mm in P. aspidiotes ) and more robust aspect. Denham et al. (2002) separated these species also by the arrangement of spikelets, noting them to be paired in P. reticulinerve and solitary in P. aspidiotes ; however, this characteristic is unreliable because the spikelets of P. reticulinerve are usually solitary and less often paired ( Renvoize 1995). Therefore, the arrangement of spikelets along the rachis has no diagnostic value for species segregation.

Oliveira & Rua (2005) described Paspalum vallsii , a species restricted to Goiás ( Brazil) and distinguished by characteristics of the rachis, spikelets, upper glume and lower lemma. These authors distinguished P. vallsii from P. aspidiotes and P. cordatum by the rachis width, which is thinner in P. vallsii , and from P. reticulinerve by the longer, solitary spikelets with the upper glume and lower lemma glabrous in P. vallsii . However, our study of the respective type specimens demonstrated that the circumscriptions of P. vallsii and the more widely distributed P. reticulinerve overlap, and we found no significant differences to recognize them as autonomous species. Although spikelets are slightly longer (ca. 1–1.5 mm) in P. vallsii , we consider this character alone insufficient for species recognition and treat P. vallsii as a synonym of P. reticulinerve .

Specimens examined: — BOLIVIA. Santa Cruz: Chiquitos, Zona del arco, en la Serrania de Santiago de Chiquitos , campo húmido muy ao lado de rocas, 10 April 2008, J.R.I. Wood 24344 et al. (UB) ; Sobre la meseta de Motacu, campo húmedo, 11 April 2015, J.R.I. Wood 24378 et al. (UB). Santa Bárbara, NO de Roboré, Chiquitos, campo húmedo, 3 October 2008, J.R.I. Wood 24674 et al. (UB). Velasco, Parque Nacional Noel Kempff M., Las Gamas, camino hacia Las Cataratas, 13 June 1994, E. Gutiérrez 1400 (MEXU) ; Parque Nacional Noel Kempff M., Campamento Las Gamas , mosaico de cerrado, campo rupestre, pampas húmedas y bosques de galería, 900 m. sm., 3 July 1993, T. Killeen 4824 et al. (SI, MO, UZS) ; Parque Nacional Noel Kempff M., Serranía de Caparuch, 13 June 1994, T. Killeen 6541 (MEXU). BRAZIL. Mato Grosso: Diamantino, Serra do Tombador , estrada de Diamantino, campos e várzeas da Chapada, March 1918, J.G. Kuhlmann 1671 (RB). Pará : Conceição do Araguaia , Redenção , area of cerrado on outskirts west of town about 4 km from center of Redenção along PA 150, 200 m.s.m., 20 February 1980, T. Plowman 8949 et al. (MO, US) ; Marabá, Serra dos Carajás, platô a 700 m de altura, campo pedregoso, 22 May 1969, P. Cavalcante 2131 ( US). Tocantins: Couto Magalhães, 16 km west of Piquizeiro along GO–70, in cerrado savanna, 400 m. s.m., 25 February 1980, T. Plowman et al. s.n. ( US 2989019). Palmeirópolis, Estrada Palmeirópolis–fazenda Itumbiara, km 30 a partir do trevo norte da cidade de Palmeirópolis, 350 m, s.d., G. Pereira-Silva 11760 et al. (CEN) ; Linha de transmissão São Salvador ( Tocantins )– Cana Brava ( Goiás ), s.d., G. Pereira-Silva 15237 et al. (CEN). São Salvador do Tocantins , estrada de acesso ao córrego Mutum (fazenda São Jorge ), área de influência indireta, 350 m. s.m., s.d., G. Pereira-Silva 678 (CEN) ; Estrada de acesso ao córrego mutum (fazenda São Jorge), área de influência indireta, s.d., G. Pereira-Silva 10678 (CEN) ; Estrada de acesso ao córrego Mutum (fazenda São Jorge), s.d., G. Pereira-Silva 11551 et al. (CEN) .

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 7. Distribution map of Paspalum reticulinerve.