Sorghastrum canescens (Hackel) Pilger

Maciel, Jefferson Rodrigues, Proença, Carolyn Elinore Barnes, Valls, José Francisco Montenegro & Oliveira, Regina Célia De, 2021, Critical review of the nomenclature and taxonomy of Sorghastrum canescens (Poaceae: Panicoideae: Andropogoneae), an endemic Brazilian species, Phytotaxa 511 (1), pp. 37-50 : 45-47

Sorghastrum canescens (Hackel) Pilger , Nat. Pflanzenfam ed. 2, 14e: 142, 1940.

≡ Sorghum canescens Hackel, In Mart. Fl. Bras. 23: 277, 1883. Type : BRAZIL. Goyaz: Villa Boa, [between February and April of 1820], Pohl 2819 (holotype W30419 !, isotype W30420 ! , isotype W30421 ! , isotype US865433 !, isotype LE9202 ! , isotype MO235276 ! ).

≡ Andropogon trichospirus Hackel, Monogr. Phan. 6: 536–537, 1889. ≡ Sorghum nutans subvar. canescens (Hackel) Roberty, Boissiera 9: 310. 1960. ( Figs. 2 , 3 , 4 ).

Description:—Annual, cespitose, rhizomes lacking; culms 25–120 cm long, erect, simple or branched at the base; nodes glabrous, without adventitious rooting. Leaf sheath glabrous to pubescent, keeled, striate, auriculate; ligule 1– 3.5 mm long, membranous; pseudoligule absent; leaf blade 15–30 × 0.5–1 cm, glabrous to pubescent, flat; prefoliation convolute. Inflorescence a terminal panicle, open, flexible, sparse-flowered, glabrous, equilateral; racemes flexuous, upward orientated, capillary. Sessile spikelet 4–5× 0.7–1 mm, yellow; callus 0.4–0.6 mm long, acute, pungent; glumes coriaceous; lower glume 3.5–4.5 mm long., ciliate at the base, yellowish with the apex castaneous; upper glume 3.5–4.5 mm long., glabrous, yellowish; sterile lemma 2.5–4 mm long., hyaline; fertile lemma hyaline, 2.5–4 mm long.; awn 35–60 mm long, 7.3–12.2 times longer than the spikelet, 2-geniculate, twisted, dark brown up to the second geniculation, yellowish from the second geniculation to the apex, pilose along the twists. Sterile, ciliate pedicels arising at each inflorescence branch node where a sessile spikelet is inserted and appressed to the sessile spikelet at base. Apical sessile spikelet of each inflorescence branch flanked by two pedicels.

Distribution, ecology and phenology:— Sorghastrum canescens is endemic to the Brazilian savannas in South America ( Fig. 2 ). This species occurs in open savannas called “campos limpos de Cerrado” in Portuguese, that are part of the Cerrado Biome ( Ribeiro & Walter 2008). Populations of S. canescens are also found in transitional vegetation composed of more trees and shaded habitats. All specimens of this species with a precise date of collection were collected in either April or May, indicating these months as the time of flowering and fruiting of the species. Under Andropogon trichospirus , but noting that the identification was based only on the description of the species, Pilger (1901) cites his collection number 463 from the area of Cuiabá-Rosário, in the state of Mato Grosso, made in April 1899, which would extend the known area of occurrence of Sorghastrum canescens more than 400 km west. Unfortunately, Pilger’s specimen could not be located.

Conservation status:— Sorghastrum canescens occurs in a wide area of the Brazilian Cerrados ( Fig. 2 ). Brazilian botanists have documented, through herbarium collections, more than 20 new populations of the species since 1950.And field observations substantiate evidence that S. canescens is a common and prolific species and presents populations with many individuals. Furthermore, some populations are recorded from areas of vegetation under variable levels of legal protection, such as the Emas National Park, the Terra Ronca State Park, and the Area under Environmental Protection of Chapada dos Veadeiros, in the state of Goiás, and in the Krahò Indian Reservation, in the state of Tocantins. Therefore, we suggest that this species should be classified as Least Concern (LC) by the IUCN criteria.

Sorghastrum canescens : — BRAZIL. — Goiás: Alto Horizonte, região da Sururuca, Fazenda Cajás, 4 May 2015, J.E.Q. Faria 4493 (RB, UB); Campos Belos, estrada de terra para Pouso Alto, 23 April 2001, M.L. Fonseca 2517 (IBGE, ICN, MO); [Catalão a Villa Boa (cidade de Goiás)], April 1844, H.A. Weddell 2675 (P); Colinas do Sul, GO-132, ca. 38 km do trevo GO-239, sentido Minaçu, e 100–150 m à direita, 13 o 53’46”S 48 o 07’38”W, 702 m, 8 April 2014, J.M. Mendoza F., A. Amaral-Santos & T.S. Reis 4252 (CEN); Flores de Goiás, estrada para a cidade de Flores de Goiás, km 1, 3 May 1985, S.P. Almeida 1070 (IBGE, UB); Formosa, Serra do Morcego, near Córrego Estrema, ca. 38 km NE of Formosa, 21 April 1966, H.S. Irwin, R. Souza, J.W. Grear & R.R. Santos 15181 (IBGE, NY, UB); [Goiás, caminho de Bacopary, after 23 March 1828 —first collection journey by Burchell after that date], W.J. Burchell 6876 (K); [id, caminho de Carreira, after 23 March 1828 —first collection journey by Burchell after that date] W.J. Burchell 6971-2 (K); Mineiros, Parque Nacional das Emas, 16 March 2005, D.G. Ribeiro 49 (FURB, IBGE, UB); Monte Alegre de Goiás, 18,8 km ao norte do rio Paranã, ao longo da rodovia Teresina-Campos Belos, 12 May 1991, J.F.M. Valls , R.N. Pittman & G.P. Silva 12909 (CEN); Niquelândia, Fazenda Traíras, estrada de terra, no km 8, trecho entre as cidades de Niquelândia-Uruaçú, 27 April 1995, M.L. Fonseca 216 (IBGE, SP); id., 13 April 1996, F.C.A. Oliveira 521 (HCF, HRB, IBGE); São Domingos, Parque Estadual Terra Ronca, 15 May 2013, J.F.M. Valls , R.T. Queiroz, A.S. Silva & R.M. Guimarães 15821 (CEN); id., 7 May 2019, J.F.M. Valls , J.G. Felipe da Silva & I.S. Gomes 17037 (CEN); Teresina de Goiás, Chapada dos Veadeiros, trecho entre as cidades de Teresina de Goiás e Cavalcante, Área de Proteção Ambiental Chapada dos Veadeiros, 5 May 1995, T.S. Filgueiras & A.G. Burman 3220 (IBGE, SP); id, km 12 da estrada GO-118 a Nova Roma, 29 April 1996, B.A.S. Pereira & D. Alvarenga 3022 (IBGE, UB); id., estrada para Vão das Almas, ponte sobre o rio dos Bois, 15 April 2004, M.L. Fonseca, R.C. Mendonça, F.C.A. Oliveira & E. Cardoso 5167 (IBGE, ICN, UB).— Maranhão: Loreto, Ilha de Balsas region between the Rio de Balsas and Parnaíba, about 35 km S of Loreto, Fazenda Santo Estevão, 26 April 1962, G. Eiten & L. Eiten 4414 (K, SP, UB).— Mato Grosso: [Barra do Garças or Nova Xavantina], campo na segunda metade da estrada de Barra do Garças a Xavantina, 13 April 1958, A. Lima 58- 3058 (IPA, K, RB).— Tocantins: Arraias, margem de pequeno rio a 10 km da saída de Arraias no Hospital Regional, em direção a Paranã, 13 May 1991, J.F.M. Valls , R.N. Pittman & G.P. Silva 12924 (CEN); id., margem sul da estrada Arrais-Paranã (TO-362), no entroncamento para Taipa, 21 km de Arraias, 13 May 1991, J.F.M. Valls , R.N. Pittman & G.P. Silva 12932 (CEN); id., rodovia TO-050, km 415, 6 km W de Arraias, 10 May 2000, G. Hatschbach, A. Schinini & E. Barbosa 70860 (IBGE, K, RB); Dianópolis, rodovia Almas-Dianópolis, 8 km antes de Dianópolis, 8 April 1997, T.B. Cavalcanti, S. Graham & G.P. Silva 2239 (CEN, IBGE, SP); Goiatins, Comunidade indígena Krahò-Morro do Boi, 15 April 2001, A. Amaral-Santos & A.R.T. Nascimento 930 (CEN); [Porto Real (now Porto Nacional), Porto do Ferreira, Abr 1829 —Burchell last collection journey in Porto Nacional], W.J. Burchell 8785 (K).

Figures

FIGURE 2. Geographic distribution of Sorghastrum canescens, S. incompletum var. incompletum, and Sorghastrum incompletum var. bipennatum.

FIGURE 3. Sorghastrum canescens. A. Habit. B. Apex of the leaf sheath with auricles, ligular region, and base of the leaf blade. C. Spikelet and awn. D. Spikelet, lower glume view. E. Spikelet, upper glume view. F. Upper glume, ventral view. G. Lower glume, ventral view. H. Base of the awn. I. Detail of the twisted region of the awn. J. Anthers. Drawn from G. Eiten & L. Eiten 4414 (UB).

FIGURE 4. Scanning electron microscopy of Sorghastrum canescens (G. Eiten & L. Eiten 4414, UB). A. Detail of the pilose region of the awn. B. Spikelet. C. Lemma surface.