Muhlenbergia versicolor Swallen, Contr. U.S. Natl. Herb. 29(4): 412. 1950.

Peterson, Paul M., Herrera Arrieta, Yolanda, Lobo Cabezas, Silvia & Romaschenko, Konstantin, 2023, Taxonomic revision of Muhlenbergia (Poaceae, Chloridoideae, Cynodonteae, Muhlenbergiinae) in Central America: phylogeny and classification, PhytoKeys 230, pp. 1-106 : 1

37. Muhlenbergia versicolor Swallen, Contr. U.S. Natl. Herb. 29(4): 412. 1950.

Fig. 10A-F

Type.

México, Oaxaca, 170 km N of Oaxaca, 13 Dec 1945, E. Hernandez-Xolocotzi & J.A. Jenkins X-810 (holotype: US-1961991!) .

Description.

Caespitose perennials. Culms (80-)100-150 cm tall, erect, with 3 or 4 nodes, strigulose below the nodes; internodes mostly glabrous. Leaf sheaths longer than the internodes, basal sheaths compressed but not strongly keeled, the old sheaths brown becoming fibrillose with age, lower sheaths short pilose; sheath auricles 3-10 mm long, hyaline, wide, becoming frayed at the apex when mature; ligules (4-)7-22 mm long, hyaline above and firm and brown below; blades 25-40 cm long, 3-5 mm wide, blades arising near the middle of the culm 12-27 cm long, often shorter than those below, conduplicate or flat, finely scaberulous to scabrous, prominently veined on the upper surface. Panicles 20-50 cm long, 1.5-6 cm wide, erect, dark green to plumbeous, sometimes tinged in purple; primary branches 4-12 cm long, ascending or spreading up to 30° from the rachis; pedicels 1-2.5 mm long. Spikelets (2.5-)3-3.5 mm long; glumes (2.5)3-3.5 mm long, subequal, unveined or faintly 1-veined, apex erose-toothed, scabrous, unawned or awned; upper glumes mostly awned, the awn 1-1.2 mm long; lemmas 2.5-3(-3.5) mm long, villous on the lower ½ to 2/3, mostly pilose along the margins near the base, the awns 10-15(-25) mm long, flexuous; callus long-pilose; paleas equal to the lemmas, moderate to densely pilose between the keels; anthers up to 1.5 mm long, purple. Caryopses 1.5 mm long, 0.3 mm wide, fusiform, reddish-brown.

Distribution.

Muhlenbergia versicolor ranges from Central México (Colima, Ciudad de México, Guanajuato, Jalisco, México, Michoacán, Morelos, Nayarit, Oaxaca, Puebla, Veracruz) to el Salvador, Guatemala, and Honduras ( Sanchez-Ken 2018).

Ecology.

This species is mainly found in oak forests, less frequent in pine-oak woodlands, rain forests, and grasslands on slopes and disturbed roadsides associated with Alnus , Salvia , Rubus , and Thalictrum ; 900-2850 m.

Comments.

Morphologically, Muhlenbergia versicolor resembles M. distichophylla but differs in having longer lemmas 2.5-3(-3.5) mm long (1.4-2.7 mm long in M. distichophylla ) and shorter sheath auricles 3-10 mm long (versus 4-26 mm long).

Muhlenbergia versicolor is a member of M. subg. Trichochloa and is found in the clade with M. breviligula , M. maxima , M. articulata Scribn., M. lehmanniana , and M. longiglumis Vasey (Fig. 1 ; Peterson et al. 2021).

Specimens examined.

El Salvador. Santa Ana: P. Galán et al. 3920 (LAGU); R. A. Carballo et al. 965 (LAGU, MO). Guatemala. Huehuetenango: San Lorenzo, 7 km S. of San Lorenzo, W.E. Harmon & J.A. Fuentes 4786 (MO); Aguacatan road, 10 km east of Huehuetenango, P.C. Standley 82073 ( US); Barranco "Palo Negro" about 10 km W of Aguacatan, L.O. Williams et al. 21850 ( US). Sololá: Lago Atitlan, M. De Koninck 146 ( US). Honduras. El Paraíso: In forest on Mt. Yuscaran, A. Molina R. 605 ( US). Francisco Morazán: San Antonio de Oriente, Guayabillas, pine forest of Guayabillas on road to Ojo de Agua, A.R. Molina 25899 (MO); Distrito Central, Tegucigalpa, alrededores de la Universidad Nacional Autonoma de Honduras, K.J. Cantarero 48 (MO, TEFH); vicinity of Suyapa, hills above Suyapa, J.R. Swallen 11277 ( US). Mexico. Chiapas: Cintalapa: Slope, near La Cienega de León 30 km N of Las Cruces, D.E. Breedlove & F. Almeda 48070 (CAS, MO). Ixtapa: Ixtapa, at Escopetazo, D.E. Breedlove & G. Davidse 53960 (SLPM, CAS, MO); near Ixtapa, D.E. Breedlove & G. Davidse 54364 (CAS, MO), D.E. Breedlove & G. Davidse 54363 (CAS, MO). Motozintla: SW side of Cerro Mozotal, 11 km NW of the junction of the road to Motozintla along the road to El Porvenir and Siltepec, D.E. Breedlove & B.M. Bartholomew 55785 (CAS, MO). La Trinitaria, 12 km al S de la Trinitaria, camino a Cd. Cuauhtemoc, E. Martínez-Salas 23905 (MEXU). D.E. Breedlove & G. Davidse 54631 (CAS) citada en Flora Mesoamericana. Teopisca: Marsh near Teopisca, D.E. Breedlove & G. Davidse 54813 (CAS, MO); slopes at W edge of Teopisca, D.E. Breedlove & J.L. Strother 46378 (CAS, MO). Villa Corzo: Above Colonia Vincente Guerrero on road to Finca Cuxtepec, D.E. Breedlove & G. Davidse 54642 (CAS, MO), D.E. Breedlove & G. Davidse 54631 (CAS, MO).

Figures

Figure 1. A, B Bayesian tree inferred from combined plastid (ndhA intron, rps 16 - trnK, rps 16 intron, rps 3, and rpl 32 - trnL) and ITS sequences. Thick branches indicate posterior probabilities of 0.95 - 1; species in bold occur in Central America; Scale bar: 2 %.

Figure 10. A-F Muhlenbergia versicolor Swallen A habit B ligule C glumes D lemma E palea F stamens, pistil, and lodicules G-K Muhlenbergia lehmanniana Henrard G habit, H ligule I glumes J floret K stamens, pistil, and lodicules. A drawn from G. B. Hinton 2324 (US- 1840807) B-F drawn from G. B. Hinton 14808 (US- 1842654) G-K drawn from H. Pittier 1468 (US).