Muhlenbergia phalaroides (Kunth) P.M. Peterson, Caldasia 31(2): 294-296, f. 7 A-B. 2009.

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

23. Muhlenbergia phalaroides (Kunth) P.M. Peterson, Caldasia 31(2): 294-296, f. 7 A-B. 2009.

Fig. 16A-B

Lycurus phalaroides Kunth, Nov. Gen. Sp. (quarto ed.) 1: 142. 1815 (1816). Type: México, Michoacán, near Valladolid, Alberca de Palangeo and Patzcuaro, Sep, F.W.H.A. Humboldt & A.J.A. Bonpland s.n. (holotype: P-00669405 [image!]; isotypes: B-W-1630, BM!, BAA-1530!, US-91988 fragm. ex P-BONPL!, US-610837 fragm. ex LE-TRIN!). Basionym.

= Muhlenbergia lycuroides Vasey ex Beal, Grass. N. Amer. 2: 239. 1896. Type: México, Jalisco, Guadalajara, Jul-Oct 1886, E. Palmer 489 (holotype: MSC; isotypes: GH-00023916 [image!], LE, MEXU, MO-2972929!, NDG-07247 [image!], NY, P-00644181 [image!], P-00644182 [image!], S14-29628 [image!], US-822925!, US-81642!, YU-000898 [image!]).

= Lycurus phleoides var. brevifolius Scribn. ex Beal, Grass. N. Amer. 2: 271. 1896. Type: México, Jalisco, plains of Guadalajara, 23 Oct 1889, C.G. Pringle 2470 (lectotype: MSC, designated by C. Reeder, Phytologia 57(4): 288. 1985; isolectotypes: BAA!, GH, MEXU, MO-2972926!, NY!, P-00644183 [image!], P-00644184 [image!], US-996049!, W-18900000580 [image!], W-19160029092 [image!]).

Description.

Perennials, intricately branched near base. Culms 10-30 cm tall, erect, mostly glabrous, usually decumbent and sprawling below, bent at the pubescent to short pilose nodes; internodes 0.4-10(-15) cm long, pubescent to short pilose. Leaf sheaths much shorter than the internodes above, hyaline near the margins, pilose near summit; ligules 0.4-1 mm long, membranous, apex truncate to deltoid, often erose and lacerate; blades 0.5-6.5 cm long, 0.5-1.2 mm wide, shorter near the base of culms, flat, folded or loosely involute, lanate above and glabrous or with scattered, short appressed hairs below, margins whitish-thickened, apex navicular, occasionally with a short seta, seta usually less than 2 mm long. Panicles 1.5-6.5 cm long, 3-8 mm wide, spiciform and spikelike, densely flowered, often interrupted below with only a few spikelets, terminal or axillary; rachis lanate to hispid, the short hairs antrorse, appressed; primary branches 1.5-7 mm long, very short, the spikelets usually in pairs, rarely 1 or 3 per terminal branch, when in pairs the lower short-pedicelled spikelet perfect, staminate or sterile and the upper longer-pedicelled spikelet usually perfect; pedicels 0.3-1.4 mm long; disarticulation usually at the base of the pedicel, each spikelet falling as a unit leaving a small cuplike tip. Spikelets 3-4 mm long, stramineous with plumbeous mottles, sometimes additionally with purplish mottles; glumes 1-2.1 mm long, shorter than the lemma, subequal, 1-3-veined; lower glumes commonly 2 or 3-veined, usually 2-awned, occasionally 1 or 3 awned, the awns 1-3 mm long, equal or subequal, scabrous, recurved; upper glumes commonly 1-veined, usually 1-awned, the awns 1-2.5 mm long; lemmas 3-4 mm long, narrowly lanceolate, 3-veined, margins hirsute to lanate and occasionally the lower ½ sparsely hairy, the hairs 0.1-0.3 mm long, apex usually awned, occasionally unawned or mucronate, the awns 1-3 mm long; paleas 2.8-3.8 mm long, hairy between the veins, the veins occasionally extending as mucros; anthers 1.3-2 mm long, yellowish. Caryopses 1.7-2 mm long, fusiform, brownish.

Distribution.

Muhlenbergia phalaroides ranges from México to South America where it is found in Argentina, Bolivia, Columbia, Ecuador, and Peru ( Reeder 1985; Sánchez and Rúgolo de Agrasar 1986; Davidse and Pohl 1994).

Ecology.

This species occurs in open grasslands and savannahs on steep rocky slopes flats, and along disturbed irrigation canals in deep clayish-loam to sandy soils associated with Baccharis , Berberis , Cheilanthes , Condalia , Dodonaea viscosa , Eragrostis , Jarava ichu Opuntia , Muhlenbergia cenchroides , M. rigida , Nassella , Plantago , Puya , and Sporobolus indicus (L.) R. Br.; 2800-3500 m.

Comments.

Muhlenbergia phalaroides is morphologically similar to M. phleoides (Kunth) Columbus known in the southwestern USA and México, and M. alopecuroides (Griseb.) P.M. Peterson & Columbus found in the southwestern USA, México, and disjunct in Argentina and Bolivia ( Reeder 1985; Davidse and Pohl 1994, Renvoize 1998; Peterson and Giraldo-Cañas 2012). Muhlenbergia alopecuroides differs from M. phalaroides in having leaf blades with terminal seta (3-)4-7(-12) mm long and ligules (2-)3-12 mm long whereas M. phleoides differs in having auriculate ligules 1-2 mm long ( Reeder 1985; Peterson 2003). These morphological differences are perhaps better recognized at the subspecific level but there are no population studies comparing these three species, other than Peterson and Morrone (1997) who investigated populations of only the amphitropical, M. alopecuroides [as Lycurus setosus (Nutt.) C. Reeder].

Muhlenbergia phalaroides probably lies within M. subg. Pseudosporobolus , although the species has not been included in a DNA-derived phylogeny, aligning with M. alopecuroides and M. phleoides ( Peterson et al. 2021). Many members of this subgenus have narrow panicles, plumbeous spikelets with unawned, mucronate or short-awned lemmas ( Peterson et al. 2010b).

Specimens examined.

Guatemala. Quetzaltenango: Chiquilaja, potreros naturales y secos, M. de Koninck 63 (US). Mexico. Chiapas: San Cristóbal: NE edge of San Cristóbal de Las Casas, D.E. Breedlove & G. Davidse 46039, 54734 (MEXU). Teopisca: N of Teopisca, D.E. Breedlove & G. Davidse 54768 (MEXU).

Figures

Figure 16. A-F Muhlenbergia pereilema P. M. Peterson A habit B ligule with auricles C portion of the inflorescence D glumes E floret F stamens, pistil, and lodicules G-L Muhlenbergia plumiseta Columbus G habit H ligule with auricles I portion of the inflorescence J bristles K floret L stamens and pistil. A-F drawn from A. S. Hitchcock 9050 (US) G-L drawn from C. G. Pringle 5962 (US).