Muhlenbergia fastigiata (J. Presl) Henrard, Meded. Rijks-Herb. 40: 59. 1921.

Peterson, Paul M., Vega, Isidoro Sanchez, Romaschenko, Konstantin, Giraldo-Canas, Diego & Rodriguez, Nancy F. Refulio, 2018, Revision of Muhlenbergia (Poaceae, Chloridoideae, Cynodonteae, Muhlenbergiinae) in Peru: classification, phylogeny, and a new species, M. romaschenkoi, PhytoKeys 114, pp. 123-206 : 150

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).

Figures

Figure 1. A, B Maximum-likelihood 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 red occur in South America; scale bar = 2 %.

Figure 8. A-E Muhlenbergia fastigiata (J. Presl) Henrard A habit B ligule C glumes D floret E stamens and pistil F-J Muhlenbergia ligularais (Hack.) Hitchc F habit G ligule H glumes I floret J stamens and pistil. Drawings from Giraldo-Canas and Peterson (2009), Peterson and Giraldo-Canas (2011) A-E drawn from P. M. Peterson, S. Laegaard, R. J. Soreng & C. R. Annable 12709 (US) F-J drawn from P. M. Peterson, S. Laegaard, R. J. Soreng & C. R. Annable 12684 (US).