Muhlenbergia coerulea (Griseb.) Mez, Repert. Spec. Nov. Regni Veg. 17:213. 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 : 143-145

6. Muhlenbergia coerulea (Griseb.) Mez, Repert. Spec. Nov. Regni Veg. 17:213. 1921. Figs 5A-D , 6A-C

Epicampes coerulea Griseb., Abh. Königl. Ges. Wiss. Göttingen 19:256. 1874. Type: Sierra de Tucumán, Den grossen isolierten Buescheln an der Cuesta de Juntas, 23 Mar 1872, P.G. Lorentz 86 (lectotype, designated here: GOET-006633 [image!]; isolectotypes: CORD-00004624!, CORD-00004625!, US-865981!).

Crypsis phleoides Kunth, Nov. Gen. Sp. (quarto ed.) 1:140. 1816, non Muhlenbergia phleoides (Kunth) Columbus. Cinna phleoides (Kunth) Kunth, Révis. Gramin. 1:67. 1829. Epicampes phleoides (Kunth) Griseb., Abh. Königl. Ges. Wiss. Göttingen 19: 256. 1874. Type: Venezuela, Sucre, Sep, F.W.H.A. von Humboldt & A.J.A. Bonpland s.n. (holotype: P!; isotype: US-A865652 fragm. ex P!).

Crypsis stricta Kunth, Nov. Gen. Sp. (quarto ed.) 1:140. 1816, non Muhlenbergia stricta (J. Presl) Kunth. Cinna stricta (Kunth) Kunth, Révis. Gramin. 1:67. 1829. Crypsinna stricta (Kunth) E. Fourn., Mexic. Pl. 2:90. 1886. Type: Peru, Prov. de los Pastos, Dec, F.W.H.A. von Humboldt & A.J.A. Bonpland s.n. (holotype: B-W; isotype: US-A865653 fragm. ex B-W!).

Epicampes coerulea var. submutica Hack., Anales Mus. Nac. Buenos Aires 13:471. 1906. Type: Argentina, Tucumán, Dep. Tafí, Cuesta de Malamala, 2500 m, 4 Feb 1904, Stuckert herb. Arg. 14900 ex Lillo 3402 (holotype: W-1916-0026677 [image!]; isotypes: CORD-00001624 [image!], LIL-000053 [image!], US3168604!).

Description.

Densely caespitose perennials. Culms 50-100(-120) cm tall, erect, rigid, hirsute below the basal, terete nodes; usually 1 node per culm; internodes mostly glabrous and scabrous. Leaf sheaths mostly 5-18 cm long, glabrous to scaberulous above, rounded near base, lower sheaths often becoming fibrous with age; ligules 8-15 mm long, firm below, strongly decurrent, often lacerate, apex obtuse to acute; blades 15-35(-45) cm long, 2-5 mm wide, tightly involute, glabrous to scaberulous below mostly scaberulous near above. Panicles (6-)10-24(-30) cm long, 6-15 mm wide, narrow, spike-like, usually plumbeous; primary branches 0.2-2.5 cm long, erect and tightly ascending appressed, floriferous to base; pedicels 0.5-4 mm long, usually shorter than the spikelets, hispid. Spikelets 5-7(-8) mm long, plumbeous, rarely 2-flowered; glumes (4-)5-7(-8) mm long, usually as long or longer than the floret, sometimes a little shorter, lanceolate, about equal, 1-nerved, scabrous, apex acuminate, unawned, mu cronate, or short-awned; lemmas (4.6-)5-6.7(-7.1) mm long, lanceolate, plumbeous, scabrous, apex acuminate, unawned, mucronate or short-awned, the awn 1-3(-4) mm long, inserted just below the apex; callus sparsely short bearded, the hairs 0.1-0.2 mm long; paleas (4.6-)5-6.5 mm long, about as long as the lemma, narrowly lanceolate, scaberulous, apex acuminate; anthers 2-3 mm long, purplish or yellowish. Caryopses 2.5-3.5 mm long, fusiform, dark reddish-brown.

Distribution.

Muhlenbergia coerulea ranges throughout the Andean Cordillera from Colombia, Venezuela, Ecuador to Argentina, Peru and Bolivia.

Ecology.

Muhlenbergia coerulea grows on rocky, often sandy slopes, derived from volcanic origins usually near arroyos associated with of Alnus , Anatherostipa obtusa (Nees & Meyen) Peñail., Aristida , Calamagrostis , Calceolaria , Festuca , Hypericum , Jarava ichu Ruiz & Pav., Lupinus , Monnina , Nassella , Oreocallis grandiflora (Lam.) R. Br., Polylepis , Puya , Rubus , Schizachyrium and cultivated Pinus ; 2450-4900 m. Flowering February through August.

Comments.

In recent literature ( Giraldo-Cañas and Peterson 2009; Peterson and Giraldo-Cañas 2011, 2012), this species was referred to as Muhlenbergia angustata (J. Presl) Kunth but the type [ Podosemum angustatum J. Presl] clearly aligns with what we had been referring to as the hybrid between this species and M. rigida . Therefore, we adopt the next available name, Muhlenbergia coerulea and change the hybrid designation to M. coerulea × M. rigida . Many specimens studied are intermediate between M. coerulea and M. rigida . These are treated as hybrids [ M. coerulea (Griseb.) Mez × M. rigida (Kunth) Kunth; Lægaard and Peterson 2001; Peterson and Giraldo-Cañas 2011, 2012] since the size, width and colour of the panicles and the surface structure and length of the glumes and lemmas, are intermediate between these two recognised species.

Muhlenbergia coerulea is deeply embedded in the M. subg. Trichochloa clade, a group of tall, rather robust perennials historically placed in Podosemum or Epicampes ( Soderstrom 1967; Peterson et al. 2010b; Fig. 1A ).

Specimens examined.

Peru. Ancash: Prov. Huaylas, Pueblo Libre, Antircán, A. Cano 11714 (USM); Prov. Huari, Huascarán National Park, Quebrada Pachachaca, D.N. Smith 12619, A. Gonzalez & D. Maldonado (USM); Quebrada Los Cedros, D.N. Smith 9892, R. Valencia & L. Minaya (CPUN); Prov. Huari, Huascarán National Park, Alpamayo-Cashampampa trail, 3950 m, 13 Mar 1985, D.N. Smith 10054 & R. Valencia (MO, USM); Prov. Recuay, between Pequipalpa and Rachacoco, L.I. Masías 44 (USM); Huascarán National Park, Auqispuquipio, D.N. Smith 12115, R. Valencia & M. Buddensiek (MO, USM); Prov. Yungay, Cordillera Blanca, 20 km ENE of Yungay, 9°6'26.2"S, 77°41'8.2"W, 3247 m, 15 Mar 2008, P.M. Peterson 21703, R.J. Soreng, M. La Torre & J.V. Rojas Fox (US, USM); quebrada Llauganuco, 24 km ENE of Yungay, 9°5'46.3"S, 77°40'19.3"W, 3309 m, 16 Mar 2008, P.M. Peterson 21720, R.J. Soreng, M. La Torre & J.V. Rojas Fox (US, USM). Arequipa: Prov. Caraveli, Quicacha, 5 May 1955, A. Guevara s.n. (USM). Ayacucho: Prov. Huanca Sancos, 19 km NW of Putajasa on road towards Huanca Sancos, 14°00'2.6"S, 74°17'14.1"W, 3900 m, 25 Feb 2002, P.M. Peterson 16268, A. Cano, M. La Torre, A Ramirez & D. Susanibar (US, USM). Cajamarca: Prov. Cajabamba, ca. 20 km WSW of Cajabamba, 7 °42'18.0"S, 78°14'1.5"W, 3263 m, 23 Mar 2008, P.M. Peterson & R.J. Soreng 21868 (US, USM); Prov. Cajamarca, La Encañada, Cerro Negro, M. Cabanillas Medina & M. Sánchez Montoya 1530 (CPUN); La Encañada, ruta Combayo-Yanacocha, I. Sánchez Vega 10574 (CPUN); N del canal Cumbe Mayo, I Sánchez -Vega U. Molau 3733 (CPUN); Cumbe Mayo, W of Cajamarca, S.A. Renvoize 4990, S. Lægaard & I. Sánchez Vega (CPUN, K, US); Pampas de Guanico, ruta a Guagal, I. Sánchez Vega 1141 (CPUN); Sais Atahualpa, de Porcón, I Sánchez Vega 2528, V. Torrel & E. Medina (CPUN); Quebrada de la Esperanza along road to Cumbe Mayo, I. Sánchez Vega & V. Torre 3289 (CPUN); Cerro Campanario, I. Sánchez Vega 6605 (CPUN); Prov. Celendin, Celendin, 3600 m, 24 Jun 1961, R. Ferreyra 15117 (USM); Prov. San Miguel, 64 km N of Cajamarca and 3 km SW of El Cobro, 3530 m, 16 Mar 2000, P.M. Peterson & N. Refulio Rodriguez 14926 (CPUN, US, USM); Prov. San Pablo, 32 km NW of Cajamarca towards San Pablo, 3470 m, 15 Mar 2000, P.M. Peterson & N. Refulio Rodriguez 14882 (US, USM); Cajamarca-Chota road, km 37-40 marker, A. Gentry 61575, C. Diaz & C. Blaney (MO, USM). Huancavelica: Prov. Huancavelica, Canyon of Rio Ichu, SW of Huancavelica, 12°48'48.2"S, 75°3'24.5"W, 4894 m, 14 Mar 2007, P.M. Peterson 20462, R.J. Soreng, K. Romaschenko & D. Susanibar (US, USM); Tayacaja, Hacienda Tocas, between Colcabamba and Paucarbamba, 3400 m, 20 Apr 1954, O. Tovar 1981 (US, USM). Huánuco: Prov. de Huánuco, Mitotambo, above Mito, R. Ferreyra 6895 (MOL, US, USM); above Mitotambo, R. Ferreyra 9434 (USM); 3-6 mi NW of Mito, J.F. Macbride and Featherstone 1929 (F, US), Mito, J.F. Macbride and Featherstone 1721 (F, US); Prov. Ambo, Huarmiragra, A. Granda 1676 (USM). Junín: Pachacaya-Huari, 3600 m, 25 Mar 1979, O. Tovar 7838 (USM); Prov. Huancayo, Cerros E of Huancayo, O. Tovar 3259 (US); above Ocopilla, near Huancayo, O. Tovar 4506 (US, USM); above Huancayo, O. Tovar 2795 (US, USM); Palián, O. Tovar 9339 (USM); Cerros E of Huancayo, O. Tovar 3259 (USM); Oroya, A.S. Hitchcock 22182 (US). La Libertad: Prov. Huancayo, Acopalca, 4000 m, 20 Jul 1945, J. Infantes Vera 406 (LIL); Prov. Bolivar, 3 km ESE of Longotea and 9 km W of Uchumarca, 7°3'27.9"S, 77°51'2.2"W, 3202 m, 31 Mar 2008, P.M. Peterson 21957, R.J. Soreng & J. Montoya Quino (US, USM); Prov. Otuzco, Trujillo-Huamachuco road, 10-15 km before Shorey, D.N. Smith & R. Vasquez 3289 (MO, USM); Larbimbambu, 2450 m, 5 Feb 1949, J. Infantes Vera 1654 (LIL); Cerro Sango, A. Sagástegui 14428 (HAO); Prov. Santiago de Chuco, Shoreyo-Truillo road, 5 km from Shoreyo, D. Smith 2339 (MO, US, USM). Lambayeque: Prov. Ferreñafe, Incahuasi, S. Llatas Q. 1934 (CPUN, HAO, USM). Piura: Prov. Huancabamba, 14 km E of Sondor on road towards Tabaconas, 2540 m, 31 Mar 2000, P.M. Peterson & N. Refulio Rodriguez 15153 (CPUN, US, USM). Puno: Chijnaya, Pueblo de Pucará, 3900 m, Mar 1964, A. Vera 107 (COL); Hacienda Caracara, entre Llave y Pucará, 3850 m, 4 Mar 1966, O. Tovar 5162 (US); Hacienda Sollocota, 3850 m, 7 Mar 1966, O. Tovar 5229 (USM); Camacani, 9 Mar 1966, 3850 m, O. Tovar 5263 (USM); Prov. Carabaya, 10 km S of Ollachea, J.D. Boeke & S. Boeke 2974 (NY, US); Prov. Chucuito, 3 km S of Pizacoma, 4050 m, 7 Mar 1999, P.M. Peterson & N. Refulio Rodriguez 14694 (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 5. A-D Muhlenbergia coerulea (Griseb.) Mez A habit B culm and panicle C ligule D spikelet E-K Muhlenbergia coerulea (Griseb.) Mez x Muhlenbergia rigida (Kunth) Kunth E culm and panicle F spikelet G floret H glumes I lemma J paleas, dorsal and ventral view K lodicules, stamens, and pistil. A-D drawn from P. M. Peterson, R. J. Soreng & J. Montoya Quino 21957 (US) E-K drawn from P. M. Peterson & N. Refulio Rodriguez 14860 (US).

Figure 6. A-C Muhlenbergia coerulea (Griseb.) Mez A habit B panicle C spikelet D-F Muhlenbergia rigida (Kunth) Kunth D habit E panicle F spikelet. Drawings from Giraldo-Canas and Peterson (2009), Peterson and Giraldo-Canas (2011). A-C drawn from S. G. Beck 7700 (LPB) D drawn from P. M. Peterson 9659 (US) E, F drawn from P. M. Peterson, C. R. Annable & J. Valdes-Reyna 10876 (US).