Muhlenbergia montana (Nutt.) Hitchc., U.S.D.A. Bull. (1915-23) 772: 145, 147. 1920.

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

16. Muhlenbergia montana (Nutt.) Hitchc., U.S.D.A. Bull. (1915-23) 772: 145, 147. 1920.

Fig. 9F-J

Calycodon montanum Nutt., J. Acad. Nat. Sci. Philadelphia ser. 2. 1:186. 1848. Type:United States, New Mexico, Santa Fe Co., in the Rocky Mountains near Santa Fe, W. Gambel s.n. (holotype: BM!; isotypes: GH, MO-992590!, PH). Basionym.

= Muhlenbergia gracilis var. enervis Scribn. ex Beal, Grass. N. Amer. 2: 242. 1896. Type: México, Chihuahua, dry ledges, Sierra Madre, 7 Oct 1887, C.G. Pringle 1413 (holotype: MSC; isotypes: GH-00024024 [image!], US-995814!, UVMVT-024031 [image!], W-1916-27712!). ≡ Muhlenbergia enervis (Scribn. ex Beal) Hitchc., Contr. U.S. Natl. Herb. 17(3): 302. 1913.

= Muhlenbergia trifida Hack., Repert. Spec. Nov. Regni Veg. 8: 518. 1910. Type: México, Michoacán, vicinity of Morelia, Quinceo, 9 Nov 1909, Bro. Arséne 3217 (holotype: W-1916-32145!; isotypes: BM, MO-843315!, MPU-026951 [image!], US!, US-86637! fragm.).

Description.

Densely caespitose perennial. Culms 10-80(-90) cm tall, erect, terete near base, glabrous below the strictly basal nodes; internodes mostly glabrous, occasionally glaucous. Leaf sheaths 2-35 cm long, longer than the lower internode, glabrous to scaberulous, often glaucous, becoming flat, loose and papery, and occasionally spirally twisted near the base; ligules 4-14(-20) mm long, membranous, decurrent, apex acute to acuminate, often lacerate; blades 6-30 cm long, 1-2.5(-3) mm wide, flat becoming loosely involute to subfiliform, somewhat stiff, scabrous below and hirsute above. Panicles 5-25 cm long, (1-)2-6 cm wide, narrow to somewhat open, loosely flowered, not dense; primary branches 0.5-10 cm long, ascending, appressed or spreading to 40° from the rachises; pedicels 2-7 mm long, longer than the spikelets, flattened, scabrous, occasionally stiffly reflexed. Spikelets 3-4.5(-7) mm long, erect, occasionally reflexed; glumes (1-)1.5-3.2(-4) mm long, ⅓ to ⅔ as long as the lemma, subequal, glabrous to scaberulous above; lower glumes 1-veined, sometimes mucronate, the mucro less tan 1 mm long; upper glumes 3-veined, 3-toothed and 3-awned, the teeth (including the awns) ⅓ to the length of the glume, and the awns up to 1.7 mm long, apex truncate to acute; lemmas 3-4.5 mm long, lanceolate, awned, often greenish or yellowish with dark green or purple mottles, scaberulous above, loosely to densely appressed-pubescent to pilose along the midvein, margins, and proximal. to ⅘, the hairs up to 0.8 mm long, occasionally glabrous, apex acute to acuminate, the awn (2-)6-25 mm long, flexuous; paleas 3-4.5 mm long, lanceolate, loosely to densely appressed-pubescent to pilose between the veins on the proximal ⅓ to ⅘, apex acute to acuminate, scaberulous; anthers 1.5-2.3 mm long, purplish. Caryopses 1.8-2 mm long, fusiform, light brown. 2 n = 20, 40 ( Herrera Arrieta 1998).

Distribution.

This species ranges from southwestern USA throughout western México to Guatemala ( Peterson et al. 2001).

Ecology.

Muhlenbergia montana grows on rocky slopes, dry meadows, ridgetops, and open grasslands, primarily in upland and mountain habitats in pine and oak forests, at elevations of 1400-3000 m.

Comments.

Muhlenbergia montana is morphologically similar to M. quadridentata but can be separated from the latter in having 3-toothed and 3-awned upper glumes with teeth 1/3 to ½ the length of the glume (the teeth are small <1/6 the length of the glumes in M. quadridentata ), lemmas that are greenish or yellowish with green mottles or purple mottles (the lemmas are greenish-plumbeous to mottled plumbeous in M. quadridentata ), and the anthers are usually 1.5-2 mm long (2-2.5 mm long in M. quadridentata ) [ Herrera Arrieta and Peterson 2007, 2018].

Muhlenbergia montana is a member of Muhlenbergia subg. Clomena , a lineage hypothesized to have originated in the Sierra Madre of México about 5.4 mya ( Peterson et al. 2021).

Specimens examined.

Guatemala. Huehuetenango: La Sierra (Tujimach), across river from San Juan Atitlan, Sierra de los Cuchumatanes. Open upper slopes, J.A. Steyermark 51989 ( US); About Laguna de Ocubila, east of Huehuetenango, dry open oak woods, P.C. Standley 82722 ( US); Chiantla, cerca del cementerio, Llano de San Nicolás, D.N. Smith 442 (MO)¸ Aldea San Nicolás, Chiantla, D.N. Smith 491 (MO). Quetzaltenango: La Esperanza, lugares secos, esteriles, M. de Koninck 132 ( US). Quiche: Between Quiche and San Pedro Jocopilas, on dry rolling hills with pine and oak forest, P.C. Standley 62453 ( US). Mexico. Chiapas: Amatenango del Valle: S of the center of Amatenango del Valle, Alush Shilom Ton 1531, (ENCB). San Cristóbalde las Casas: "El Banco" sobre el libramiento E a San Cristobal, km 4 carr. San Cristobal de Las Casas-Tenejapa, A. Miranda S. s/n (MEXU); D.E. Breedlove & G. Davidse 55174 (CAS) cited in Reeder (1994).

Figures

Figure 9. A-E Muhlenbergia flabellata Mez. A habit B ligule C glumes D floret E floret F-J Muhlenbergia montana (Nutt.) Hitchc F habit G inflorescence H glumes I upper glume J florets. A, B, D, E drawn from W. C. Burger & L. Gomez P. 8309 (US- 2695054) C drawn from G. Davidse 24971 (US- 3014559) F-J drawn from A. S. Hitchcock 3143 (US- 995116).