9. Muhlenbergia fastigiata (J. Presl) Henrard, Meded. Rijks-Herb. 40: 59. 1921. Fig. 8A-E

Sporobolus fastigiatus J. Presl, Reliq. Haenk. 1 (4-5): 241. 1830. Type: Peru, Haenke s.n. (holotype: PR, isotypes: PRC-450197 [image!], US-3048470! fragm. ex PR).

Muhlenbergia cleefii Lægaard, Caldasia 17 (82-85): 409-411. 1995. Type: Colombia, Boyacá, Sierra Nevada del Cocuy, Alto Valle de Lagunilla, páramo pantanoso al sur de la Laguna Cuadrada, 4060 m, 26 sep 1972, A. Cleef & P.A. Florschutz 5578 (holotype: COL!; isotypes: U-0007997 [image!], US-2785756!).

Description.

Dense mat-forming perennials with scaly rhizomes, the acute scales 4.5-8.1 (-10) mm long, the rhizomes 1-2 (-2.5) mm in diameter. Culms 2-8 (-11) cm long, mostly erect, 2-3 (4) mm diameter below; internodes 1-10 mm long, compressed. Leaf sheaths 3-6 (-10) mm long, distichous, overlapping, margins hyaline; ligules 6-1.4 mm long, membranous, decurrent, apex acute to obtuse; blades 2.5-8.5 mm long, 0.6-1.1 mm wide, involute, arcuate, glabrous to finely papillose, margins scabrous, apex navicular, often pungent. Panicles 1-2 cm long, 1-5 mm wide, contracted, narrow, usually exserted with 3-9 nodes; primary branches 0.4-1 cm long, ascending, solitary at a node; rachis papillose-roughened just below the spikelets. Spikelets (1.8--) 2-2.5 mm long, plumbeous; glumes (0.8-) 1-1.6 mm long,about ½ as long as the floret, subequal, 1-veined, rarely 2-veined, apex acute to obtuse; lemmas (1.7-) 1.9-2.4 mm long, 3-veined, glabrous, plumbeous, apex acute, mucronate, the mucros less than 0.3 mm long; paleas (1.6-) 1.8-2.4 mm long, 2-veined, glabrous; anthers 1-1.7 mm long, yellow or purple. Caryopses 1-1.3 mm long, about 0.4 mm wide, ellipsoid, dark brown.

Distribution.

Muhlenbergia fastigiata is found in South America in the Andean highlands of Argentina, Bolivia, Chile, Colombia, and Peru (Morden 1985; Morden and Hatch 1996).

Ecology.

Muhlenbergia fastigiata occurs on grassy flats, playas, slopes, rock outcrops, near gravelly creeks and lake margins in granitic and calcareous soils associated with Baccharis, Berberis, Calamagrostis, Ephedra, Festuca, Jarava, Margyricarpus, Muhlenbergia, ligularis, M. peruviana, and Nassella; 3000-4900 m.

Comments.

Morphologically, M. fastigiata can sometimes be confused with the distantly related M. ligularis ( M. subg. Bealia; Fig. 1B). However, the former has well developed rhizomes (absent in M. ligularis) and tightly involute, acuate leaf blades (versus flat and straight). Muhlenbergia richardsonis (Trin.) Rydb., a wide ranging North American species, is also morphologically similar to M. fastigiata in most characters, although M. richardsonis has a taller habit and differes in leaf anatomy (Morden 1985; Morden and Hatch 1996). Aciachne acicularis Lægaard and A. pulvinata Benth., two small, compact, mat-forming perennials, can also be mistaken for M. fastigiata . However, both species of Aciachne ( Pooideae: Stipeae) have longer spikelets ranging from 3.8-6 mm long, glumes that are 3-5-veined, and tightly overlapping lemma margins (Renvoize 1998; Giraldo-Cañas and Peterson 2009).

Muhlenbergia fastigiata is sister to the North American, M. richardsonis in M. subg. Pseudosporobolus [Fig. 1; Peterson et al. 2010b].

Specimens examined.

Peru. Ancash: Recuay, Cordillera Blanca, 39 km S of Catac on road towards Raquia, 3980 m, 21 Mar 1997, P.M. Peterson 13825 & N. Refulio Rodriguez (US, USM); Cordillera Negra, E slope of Cerro Pullicharca (Purac), ca. 1.5 km W of hwy 109 and then 3.6 km S of Tapacocha along Rio Santa, 9°55'39.4"S, 77°23'45.3"W, 3822 m, 9 Mar 2008, P.M. Peterson 21512, R.J. Soreng, M.I. La Torre & J.V. Rojas Fox (US, USM); between Santa Rosa and Araranca 12 Apr 1915, O.F. Cook & G.B. Gilbert 168 (US). Arequipa: Prov. Caylloma, Valle de Colca, Chiray-Tuti, 3900 m, 12 Jan 1999, S.G. Beck 26354 (LPB); Prov. Caylloma, Pampa Cañahuas, "Grama dulce", 4200 m, 3 Jul 2001, M. Rodríguez Diaz 1130 (USM). Cajamarca: Prov. Hualgayoc, 8 km NE of Hualgayoc on hwy 3N towards Bambamarca, 3080 m, 17 Mar 2000, P.M. Peterson & N. Refulio Rodriguez 14950 (CPUN, US, USM). Kanzel, above Sunchubamba, 3680 m, 6 Aug 1957, H. Ellenberg 1852 (US). Cusco: Chumbivilias, Rio de Velille, 3850 m, C. Vargas C. 14084 (US); Espinar, alrededores de Yauri, 3900 m, 26 Mar 1956, 26 Mar 1956, C. Vargas C. 11209 (US). Huancavelica: Huancavelica, Canyon of Rio Ichu, SW of Huancavelica ca. 5 km on Hwy 3 to Santa Ines and Ayacucho, 12°48'48.2"S, 75°3'24.5"W, 4894 m, 14 Mar 2007, P.M. Peterson 20463, R.J. Soreng, K. Romaschenko & D. Susanibar Cruz (US, USM); Tayacaja, Just above Chuquitambo, 4 km SW of Pazo, 3975 m, 9 Apr 1997, P.M. Peterson 14151 & O. Tovar (US, USM). Junín: Prov. Huancayo, Acopalca, 3900 m, 25 Jul 1945, J. Infantes Vera s.n. (LIL); Prov. Huancayo, Acopalca, 4000 m, 20 July 1947, J. Infantes Vera 446 (LIL); entre Tarma y La Oroya, 3700 m, A. Weberbauer 2525 (MOL); Hacienda Cachi-Cachi, 4000 m, 22 Oct 1950, O. Velarde Nuñez 2869 (MOL); Jauja, 34 km SE of La Oroya on road towards Jauja, 3600 m, 9 Apr 1997, P.M. Peterson 14125 & O. Tovar (US, USM); Jauja, Tarma-Jauja road, 28 km from Tarma, 11°35'S, 75°38'W, 3950 m, 10 Jan 1984, D.N. Smith 5694 (MO, US); Junín, SE shore of Lago Chinchay Cocha (Junin) and 8 km S of Huayre, 4110 m, 7 Apr 1997, P.M. Peterson 14096 & O. Tovar (US, USM); Yauli, 156 km W of Lima just above Yauli, 4120 m, 5 Apr 1997, P.M. Peterson 14040 & O. Tovar (US, USM); Yauli, La Oroya, 30 Nov 1924, F.L. Stevens 1 (US); Oroyo, 23 Oct 1923, A.S. Hitchcock 22135 (US), 21 Feb 1954, Hirsch s,n. (US), Stevens 1 (US); entre Tarma y Oroya, 3400 m, 29 Jun 1948, R. Ferreyra 3828 (MOL, US, USM); ca. 24 km W of Tarma, 4050 m, 6 May 1979, Teppner 79/387 (US). La Libertad: Prov. Huamachuco, Cangau Sartimbamba, 3200 m, 28 Jan 1952, J. Infantes Vera 4072 (LIL); Prov. Huamachuco, Cangau Sartimbamba, 4000 m, 29 Jan 1952, J. Infantes Vera 4045 (LIL); Prov. Huamachuco, Huailillas, 3800 m, 8 Aug 1951, J. Infantes Vera s.n. (LIL). Lima: Provincia Huarochiri, Chilca, Bella Vista, 3800 m, 5 Jun 1940, E. Asplund 11436 (NY, US); road from Lima to Huancayo, 3300 m, 20 May 1981, G. Sullivan, K. Young, S. Sánchez & D. Soejarto 1021 (MO, US). Pasco: Pasco, 8 km W of NW arm of Laguna de Junín, 10°55'51.9"S, 76°18'8.6"W, 4141 m, 5 Mar 2007, P.M. Peterson 20313, R.J. Soreng & K. Romashchenko (US, USM). Puno: Chucuito, 3 km NE of Zepita on road towards Copani, 3820 m, 5 Mar 1999, P.M. Peterson 14631, N. Refulio Rodriguez & F. Salvador Perez (US, USM); 20 km E of Huacullani on road towards Desaguadero, 3880 m, 5 Mar 1999, P.M. Peterson 14645, N. Refulio Rodriguez & F. Salvador Perez (US, USM); 5 km S of Kelluyo, 3860 m, 7 Mar 1999, P.M. Peterson 14686, N. Refulio Rodriguez & F. Salvador Perez (US, USM); El Collao, 11 km E of Santa Rosa and 5 km W of Mazo Cruz, 3880 m, 2 Mar 1999, P.M. Peterson 14598, N. Refulio Rodriguez & F. Salvador Perez (US, USM); 9 km N of Conduriri and 63 km S of Ilave along the Rio Huenque, 3820 m, 3 Mar 1999, P.M. Peterson 14600, N. Refulio Rodriguez & F. Salvador Perez (US, USM); Provincia Melgar, 7 km WNW of Santa. Rosa, 14°35'54.9"S, 70°51'34.7"W, 4002 m, 23 Mar 2007, P.M. Peterson 20605, R.J. Soreng & K. Romashchenko (US, USM); SW of Juliaca ca. 8 km on Hwy 30 to Arequipa, 15°32'37.2"S, 70°12'55.9"W, 3854 m, 31 Mar 2007, P.M. Peterson 20715, R.J. Soreng, K. Romaschenko & S. Gonzalez Elizondo (US, USM); Puno, 2 km N of Laraquerion road towards Puno, 16°6'59.1"S, 70°1'59.1"W, 3940 m, 18 Apr 2004, P.M. Peterson 18327 & N. Refulio Rodriguez (US, USM); San Ro man, 4 km E of Santa Lucia, 15°41'4.2"S, 70°34'8.0"W, 4030 m, 19 Apr 2004, P.M. Peterson 18332 & N. Refulio Rodriguez (US, USM); 21 km W of Santa Lucia and 5 km E of Puente Cañuma (Laguna Lagunillas), 15°40'4.1"S, 70°47'4.4"W, 4260 m, 20 Apr 2004, P.M. Peterson 18344 & N. Refulio Rodriguez (US, USM); Camjata Hacienda, Capachica Peninsula, Lake Titicaca, Tutin 975 (NY); between Juliaca and Cusco, 3880 m, 27 Nov 1923, A.S. Hitchcock 22448 (US); Hacienda Pairumani, 20 mi SW of Llave, 3900 m, 21 Jul 1946, O.P. Pearson & A. Pearson 14 (US); between Puno and Laguna Umayo, N of Puno, 3970 m, 12 Sep 1959, H.G. Barclay 9265 (US). Tacna: Cordillera Volcan Tacora, Ancara, Werderman 1138 (NY, US); Tarata, 11 km NW of Yabroco on road towards Cano, 3680 m, 16 Mar 1999, P.M. Peterson 14814, N. Refulio Rodriguez & F. Salvador Perez (US, USM).