Muhlenbergia diversiglumis Trin., Mem . Acad. Imp. Sci. Saint-Petersbourg , Ser . 6, Sci. Math., Seconde Pt. Sci. Nat. 6,4(3-4):298. 1841.

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

8. Muhlenbergia diversiglumis Trin., Mem. Acad. Imp. Sci. Saint-Petersbourg, Ser. 6, Sci. Math., Seconde Pt. Sci. Nat. 6,4(3-4):298. 1841.

Fig. 8A-D

Type.

México, Porto Pedro, Karwinsky 1393 (lectotype, designated here: LE-TRIN-1497.01!; isolectotypes: LE-TRIN-1497.02!, LE-TRIN-1497.03!, US-84831 fragm. ex LE-TRIN!, W-0002564!).

Description.

Sprawling annuals. Culms 16-50 cm tall, decumbent, rooting at the lower nodes; nodes retrorsely pilose; internodes smooth or scabridulous. Leaf s heaths 1.5-8.5 cm long, sparsely or densely pilose, hairs to 3 mm long, papillose-based; ligules 0.5-0.8 mm long, membranous, apex truncate, erose; blades 2-6 cm long, 1.5-4 mm wide, flat, bases distinctly narrowed to the junction with the sheath, surfaces scabridulous and sparsely pilose, hairs papillose-based. Panicles 6-10.5 cm long, 2.0-4.5 cm wide, open; primary branches 0.8-3.5 cm long, secund, spreading at right angles or somewhat reflexed usually lying to one side with 2-5 spikelets; secondary branches not developed; pedicels 1-5 mm long, scabrous or shortly pilose, hairs papillose-based; disarticulation at the base of the primary branches where there is a weak and contorted stipe. Spikelets 4-8 mm long, dimorphic with respect to the glumes, proximal spikelets on each branch almost sessile; glumes of proximal spikelets on each branch subequal, 0.2-0.7 mm long, orbicular, truncate, often erose or irregularly toothed, unawned; glumes of distal spikelets on each branch markedly unequal; lower glumes to 8 mm long, 1-veined, acute, usually awned, awns 0.5-3 mm; upper glumes orbicular, acute, sometimes awn-tipped; lemmas 4.0-7.6 mm long, linear to broadly lanceolate, light greenish, smooth or scabrous, usually with greenish veins, apices acuminate, awned, awns 6-19 mm long, usually straight, scabrous; paleas 3.7-6.8 mm long, narrowly lanceolate, coarsely papillate or almost smooth, 2-keeled, the veins prominent, scabrous, greenish, sometimes extending as minute awns, acuminate; anthers 0.4-0.8 mm long, yellowish. Caryopses 1.8-3 mm long, oblong-ovoid, flattened, brownish. 2 n = 20.

Distribution.

The species is native to North America, Central America, Colombia, Venezuela, Ecuador, Peru, and Argentina ( Peterson and Annable 1991; Peterson et al. 2001).

Ecology.

Muhlenbergia diversiglumis grows on moist cliffs, along water courses, sandy slopes, and road cuts, primarily in moist shaded environments of broadleaf evergreen forests and pine-oak forests; 600-2500 m.

Comments.

Muhlenbergia diversiglumis can be differentiated from M. ciliata , M. microsperma , and M. romaschenkoi in having secund panicles (versus not secund in the latter three species) with each primary branch consisting of 2-5 dimorphic spikelets where the proximal spikelets have short orbicular glumes less than 1 mm long, and the distal spikelets have glumes up to 8 mm long ( Peterson and Annable 1991; Giraldo-Cañas and Peterson 2009).

Muhlenbergia diversiglumis is a member of M. subg. Muhlenbergia and is sister to M. alamosae Vasey, a species from México ( Peterson et al. 2021).

Specimens examined.

Costa Rica. Alajuela: 1 km S of Carrizal, R.W. Pohl & G. Davidse 11500 ( US). Cartago: San Ramón, E of San José, open grassy roadside, R.W. Pohl & Mark Gabel 13678 (MO); Road crossing of Río Reventado between Llano Grande and Tierra Blanca, gravelly river banks, R.W. Pohl & M. Lucas 13092 (MO). Heredia: Porrosati, 2 km by road N of Porrosati, R.W. Pohl & M. Gabel 13672 (MO); Carrizal, H. Pittier 786 ( US); Barba, cultures a La Esmeralda, A. Tonduz 1692 ( US). Puntarenas: Cordillera de Tilarán, W. Haber & W. Zuchowski 10891 (MO, INB). San José: Aserri, Cuenca del Pirris-Damas, Cerros Caraigres, Falda S, Quebrada Concha, en el camino viejo a Bijagual, J.F. Morales 5913 (MO, INB); León Cortés Castro, Z.P. Caraigres, Cuenca del Pirris-Damas, Fila El Alto. J.F. Morales 5933 (MO, INB), Pérez Zeledón, P. N. Chirripó camino a Chirripó a orilla del sendero, Cuenca Térraba- Sierpe, E. Alfaro, et al. 966 (CR, INB); Hacienda La Esperanza, La Palma, O. Jiménez 963 (CR). San Francisco de Guadalupe, cultivos, O. Jiménez s.n. ( US); Jardines de San Francisco de Guadalupe, H. Pittier 9068 ( US); 11 km N of San Isidro de El General along the Carretera Interamericana, R.W. Pohl & G. Davidse 11570 ( US); Between Aserrí and Tarbaca, P.C. Standley 41352 ( US); vicinity of Santa María de Dota, moist forest, P.C. Standley 41831 ( US); vicinity of Santa María de Dota, P.C. Standley & J. Valerio 43215 ( US); La Verbena de Alajuelita, A. Tonduz 9084 ( US). El Salvador. Ahuachapán: Parque Nacional El Imposible: San Benito, al S del enganche de los ríos Venado y Escalares, E. Sandoval & F. Pérez 1470 (MO). San Salvador: Volcán San Salvador, el Boqueron, disturbed secondary forest bordering pasture and cafetale, A. Monro et al. 2179 (MO); Volcano of San Salvador, A.S. Hitchcock 8929 ( US); Volcano of San Salvador, A.S. Hitchcock 8939 ( US); Volcano of San Salvador, A.S. Hitchcock 8940 ( US). Guatemala. Alta Verapaz: near San Cristóbal Verapaz, wet thickets and second growth forest, L.O. Williams et al. 42228 (MO); Coban, H. Von Turckheim s.c. ( US); Coban, Maisfeldem. unter Kiefernald, H. Von Turckheim 3988 ( US). Guatemala: Guatemala City, A.S. Hitchcock 9049 ( US). Huehuetenango: 21 mi NW of Huehuetenango on Pan American Hwy. 1, P.M. Peterson & C.R. Annable 4682 (MO). Jalapa: Mountains along the road between Jalapa and Paraiso, P.C. Standley 77358 ( US). Jutiapa: Volcan Chingo, W.C. Shannon 3699 ( US). Quiche: Chichicastenango, 4 km S of Chichicastenango, steep wooded hillside dominated by pine and oak, W.E. Harmon 4613 (MO). San Marcos: Wet mountain forest near Aldea Fraternidad, between San Rafael Pie de la Cuesta and Palo GPoales, west facing slope of the Sierra Madre Mountains, L.O. Williams et al. 25993; L.O. Williams et al. 25971 ( US); Montane cloud forest area on outer slopes of Tajumulco Volcano, Sierra Madre Mountains about 8-10 km west of San Marcos, L.O. Williams et al. 26928 ( US). Honduras. Francisco Morazán: Tatumbla, Cerro Uyuca, R.W. Pohl 12493 (MO); San Antonio del Oriente, J.R. Swallen 10975 ( US); forest with with Pinus and Liquidambar entre Peña Blanca y Lo de Ponce, L.O. Williams & A. Molina R. 17126 ( US). Mexico. Chiapas. Angel Albino Corzo: slopes of Río Cuxtepec. along stream below Finca Cuxtepec, D.E. Breedlove & J.L. Strother 46692 (CAS, MO). Motozintla: Sierra Madre de Chiapas 5 mi NW of Motozintla de Mendoza on road to El Porvenir, P.M. Peterson & C.R. Annable 4707 (ENCB, MEXU, US, MO); W 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 55714 (CAS, MO). Zinancantán: Hwy 190, 10 mi SE of the road to Simojovel paraje of Granadia, D.E. Breedlove 7276 (ENCB).

Figures

Figure 8. A-D Muhlenbergia diversiglumis Trin. A habit B floret C glumes D ligule E-H Muhlenbergia implicata (Kunth) Kunth E habit F floret G glumes H ligule. A-D drawn from P. M. Peterson & C. R. Annable 4158 (US, WS). E-H drawn from P. M. Peterson & C. R. Annable 4598 (US, WS).