Muhlenbergia flabellata Mez, Repert. Spec. Nov. Regni Veg. 17: 213. 1921.

9. Muhlenbergia flabellata Mez, Repert. Spec. Nov. Regni Veg. 17: 213. 1921. View in CoL View at ENA

Fig. 9A-E View Figure 9

Type.

Costa Rica, San José, Cerro de Buena Vista , 3000m, 19 Jan 1891, H. Pittier 3372 ( lectotype, designated here: G-00192109 [image!]; isolectotypes G-00192054 [image!], US-577110!) .

Description.

Caespitose and sprawling perennials. Culms 25-45 cm long, densely branched near base, decumbent and rooting below; internodes glabrous. Leaf sheaths much overlapping, flabellately arranged, glabrous, margins membranous, old sheaths flattened and papery; ligules (2.5-)3-8 mm long, membranous, hyaline, margins entire, decurrent, apex acute; blades 2-5 cm long, 1-2 mm wide, flattened to folded or involute, mainly basal, strongly ridged above with short stiff hairs, scabrous below. Panicles 3-9(-15) cm long, 2-3 cm wide, few-flowered, narrow, short-exserted, dark green; primary branches mostly 1-2 cm long, sometimes purplish with loosely appressed and ascending branches, spreading up to 30° from the culm axis, central axis slightly flattened, 2-ribbed, scabrous; pedicels 0.2-1 mm long, scabrous. Spikelets 3-4 mm long, erect, plumbeous to dark olivaceous; glumes 1.2-2 mm long, subequal, scabrid, apex obtuse to truncate, unawned; lower glumes 1.2-1.6 mm long, ovate, usually 1-veined, sometimes unveined; upper glumes 1.6-2 mm long, half as long as the lemma, oblong-obovate, usually 3-veined, but sometimes very faint, 2 or 3-toothed, the teeth 0.3-0.6 mm long, about 1/3 the length of the glume; lemmas 3-4 mm long, lanceolate, pilose below and along margins, the hairs mostly less than 1 mm long, the callus hairy, apex awned, the awns 4-8 mm long, flexuous, scabrous, olive-green, arising from a bifid apex, the teeth up to 0.5 mm long; paleas 3-4 mm long, as long as the lemma, olive-green, scabrous; anthers 1.8-2.1 mm long, fusiform, purple.

Distribution.

The species is endemic to Costa Rica and Panama ( Peterson et al. 2001).

Ecology.

Muhlenbergia flabellata occurs in páramos between 3100-3500 m often associated with Chusquea subtessellata Hitchc., Hypericum , ssp., Comaristaphylos arbutoides Lindl., Garrya laurifolia Hartw. ex Benth., and Buddleja nitida Benth.

Comments.

Muhlenbergia flabellata is a member of M. subg. Clomena and within this clade it is sister to M. quadridentata , a species primarily restricted to higher elevations that is common in México and extends into Guatemala ( Peterson et al. 2021). Muhlenbergia flabellata can be separated from M. quadridentata in having short leaf blades 2-5 cm long (5-15 cm long in M. quadridentata ), short upper glumes 1.6-2 mm long [versus (3-)3.2-4 mm long in M. quadridentata ], and paleas scabrous throughout (versus pilose on the proximal ½ in M. quadridentata ) [ Peterson et al. 2007b; Herrera Arrieta and Peterson 2018].

Specimens examined.

Costa Rica. Cartago: Paraíso, Cerro de la Muerte, Cordillera de Salamanca , near summit of Cerro Sátira, S. Horn 35 (CR); Paraíso, Cerro de la Muerte, M. Kappelle et al. 2377 (CR). Pérez Zeledón: R. F. Los Santos, Cerro Bubis, A. Estrada et al. 2769 (CR); P. N. Chirripó, parte superior (norte) del Valle de los Conejos, J. Gómez 5339 (CR); R.F. Los Santos Alrededores de las torres de TV, cerro Buenavista, L. Gómez 6354 (CR); P. N. Chirripó, alrededores de refugio, parte inferior del valle de los Conejos, J. Gómez-L. 4503 (USJ); P. N. Chirripó, Cordillera de Salamanca , S facing slope of the Valle de los Conejos , about 1 km S of Cerro Nuevo, S. Horn 59 (CR); P.N. Chirripó, Valle de los Conejos, R. Ocampo 1466 (CR); P.N. Chirripó, Valle de los Conejos, R. Ocampo 1489 (CR); Rivas, A. Rodríguez 6422 (INB); Perez Zeledon , Rivas, A. Rodríguez 6541 (INB); P.N. Chirripó, refugio Los Crestones, G. Vargas et al. 340 (USJ); disturbed paramo, Cerro de la Muerte, R. Chazdon 447 (CR); Cordillera de Talamanca , Cerro de la Muerte , summit of Cerro Buvis, R.W. Pohl & G. Davidse 11621 (US); Direct line from Hotel La Georgina to Cerro Frio of the Cerro Buenavista complex ( Cerro de la Muerte ), area with television and radio towers, G. Davidse 24971 ( US, MO); Open paramo formation with stands of Chusquea bamboo 1-2.5 m tall and areas of short-burned forest and original forest 5-15 m tall in protected sites, along the trail to the Valle de los Leones and the lower part of theValle de los Conejos along the upper Rio Talari, W. Burger & L.D. Gomez 8309 (US). San Jose: W.C. Burger & R. Liesner 7467 (MO); Chirripó, G. Davidse & R. W. Pohl 1541 (MO); Buenavista, A. Jiménez 2666 (MO); Parque Nacional Chirripó, Páramo near Albergues de los Crestones, along Rio Talari near trail to Valle de los Conejos, J. G. Pruski et al. 3904 (MO); Buenavista, A. Weston 5846 (MO); Cerro Buenavista, P.M. Peterson, S. Lobo, J. Sánchez & R. Chacón 22855 (CR, US); P. N. Chirripó Open paramo formation with stands of Chuquea bamboo 1-2.5 m tall on slopes and in the valley, short grasses and very short ( 30 cm)shrubs on the exposed ridges, Valle de los Conejos (upper río) Talari and trails to Cerro Chirripó and the Valle de Los Lagos , W.C. Burger & R. Liesner 7353 (CR); P. N. Chirripó, A. Chaverri et al. 1026 (CR); P. N. Chirripó Valle de los Conejos, A. Chaverri et al. 1172 (CR) , Panama. Bocas del Toro: Fábrega, A. Weston 10190 (MO) .