Muhlenbergia mutica (Rupr. ex E. Fourn.) Hitchc., N. Amer. Fl. 17(6): 459. 1935.

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

18. Muhlenbergia mutica (Rupr. ex E. Fourn.) Hitchc., N. Amer. Fl. 17(6): 459. 1935.

Fig. 14A-I

Epicampes mutica Rupr. ex E. Fourn., Mexic. Pl. 2: 87. Type: México, Veracruz, Mirador, Zacuapan, and Cantaranas, 1840, H.G. Galeotti 5797 (lectotype, designated by T.R. Soderstrom in Contr. U.S. Natl. Herb. 34(4): 141. 1967: P; isolectotype: US-865973! fragm. ex P). Basionym.

= Epicampes gigantea E. Fourn., Mexic. Pl. 2:88. 1886. Muhlenbergia gigantea (E. Fourn.) Hitchc., N. Amer. Fl. 17(6): 460. 1935. Type: México, Veracruz, Orizaba, Río Blanco, 30 Sep 1886, E. Bourgeau 3137 (lectotype, designated here: P-02265396 [image!]; isolectotypes: G-00099412 [image!], MPU-027109 [image!], P-02265395 [image!]; S14-29388 [image!], US-865978 fragm!, US-865977 fragm!).

= Epicampes bourgeaei E. Fourn., Mexic. Pl. 2:88. 1886. Type: México, Veracruz, Escamala, Refrou D’Orizaba, 26 Aug 1866, E. Bourgeau 2973 (holotype: P; isotypes: K!, US-A0865984! fragm.).

= Epicampes bourgeaei var. mutica E. Fourn., Mexic. Pl. 2:88. 1886. Type: México, Veracruz, Mirador, Nov 1841, F. M. Liebmann 678 (lectotype: US-207466!, designated by Herrera Arrieta and Peterson, Sida, Bot. Misc. 29: 35. 2007; isolectotypes: K!, US-207465!).

= Epicampes expansa E. Fourn., Mexic. Pl. 2:88. 1886. Type: México, Orizaba, M. Botteri & Sumichrast 104 (holotype: P!; isotype: US-865979! fragm).

= Epicampes laxiuscula E. Fourn., Mexic. Pl. 2:88. 1886. Type: México, Orizaba, M. Botteri 155 (syntype: P?; isosyntypes: BM-000938656 [image!], US-865975! fragm.).

= Epicampes ehrenbergii Mez, Repert. Spec. Nov. Regni Veg. 17: 212. 1921. Type: México, Cuesta de Pinolco, C. Ehrenberg 1156 (holotype: B?; isotype: US-A0865980! fragm.).

= Muhlenbergia alta Hitchc., N. Amer. Fl. 17(6): 461. 1935. Type: México, Jalisco, hills E of Zapotlán, 25 Sep 1910, A.S. Hitchcock 7180 (holotype: US-998980!).

= Muhlenbergia magna Hitchc., N. Amer. Fl. 17(6): 460. 1935. Type: México, Jalisco, under cool cliffs of barranca near Guadalajara, 3 Nov 1890, C.G. Pringle 3335 (holotype: US-825277!; isotypes: BR-0000006883416 [image!], BR-0000006883744 [image!], CM-2820 [image!], E-00531666, F-73213 [image!], G-00099367 [image!], G-00099368 [image!], GOET-006639 [image!], KFTA-0000246 [image!], MEXU-00004527 [image!], MEXU-00004528 [image!], MO-105133!, MO-1837821!, MU-000000018 [image!], MU-000107304 [image!], US-998977!), W-18910001067 [image!].

Description.

Strongly caespitose perennials. Culms 120-300 cm tall, erect, compressed-keeled near the base, glabrous below the nodes to sometimes scaberulous. Leaf sheaths 12-32 cm long, shorter than internodes, sometimes purplish near base, often changing to brown with age, keels prominent and glabrous, lacking auricles; ligules (5-)8-15 mm long, membranous, apex lacerate; blades 35-110 cm long, 5-10 mm wide, flattened, scaberulous adaxially and glabrous abaxially, margins and keels serrate. Panicles 35-100 long, (8-)15-30 cm wide, purple or brown-purplish, branches ascending or pendulous spreading up to 60° from culm axis; primary branches 6-25 cm long, usually 15-20 cm long below, naked near the base, pendulous to flexuous; pedicels 0.2- 2.5 mm long, generally shorter than spikelets, scaberulous. Spikelets 1.3-2.6(-3) mm long, erect, purple to brownish-purple; glumes 1.3-2.6(-3) mm long, ovate, generally longer than florets, subequal, 1-veined, often translucent, usually glabrous to scaberulous, apex acute to obtuse; lemmas 1.3-2.3 mm long, oblong, awnless, rarely mucronate, glabrous; paleas 1.3-2.3 mm long, glabrous, apex acute to obtuse; anthers 0.9-1.3 mm long, yellow to purplish. Caryopses 1-1.3 mm long, fusiform, reddish-brown. 2 n = 20, 24.

Distribution.

Muhlenbergia mutica ranges from Chihuahua, Sinaloa, and Durango, México south to Oaxaca, Veracruz, and Chiapas ( Herrera Arrieta and Peterson 2007, 2018).

Ecology.

The species grows among pines or pine-oak forests and tropical forests with Liquidambar , Nyssa , and Sabal ; 600-2300 m.

Comments.

Muhlenbergia mutica can be separated morphologically from M. robusta in having wider panicles (8-)15-30 cm wide (2-8 cm wide in M. robusta ) and non-auriculate leaf sheaths [auricles 2-4(-10) mm long in M. robusta ] (Herrera Arrieta and Peterson 2018). Muhlenbergia mutica is a member of M. subg. Trichochloa , and in a recent study was found sister to M. virletii (E. Fourn.) Soderstr., another Mexican endemic ( Peterson et al. 2021).

Soderstrom (1967) chose to recognize M. mutica and M. gigantea , stating, "The only character to separate the two is the length of the glumes in relation to the floret. It ( M. mutica ) is most closely related to and doubtfully distinct from M. gigantea ." After careful study of the isolectotypes attributed to M. mutica and M. gigantea (both housed at US), we find no differences in glume length, and they appear to represent specimens of a single species. Therefore, we place M. gigantea (younger name) as a synonym of M. mutica in our treatment.

Specimens examined.

Mexico. Chiapas. Cintalapa: 12 km S of’ Mexican hwy 190 near Rizo de Oro, Crest of the Sierra near the microwave station of La mina, D.E. Breedlove 20641 (ENCB); 23 km W of Las Cruces along road to La Mina Microwave Station, D.E. Breedlove & G. Davidse 54111 (CAS, MO); Slope, near La Cienega de Leon 30 km N of Las Cruces, D.E. Breedlove & F. Almeda 48041 (CAS, MO). Ixtapa: near Ixtapa, D.E. Breedlove & G. Davidse 54301 (CAS, MO); Near the Zinacantán Paraje of Muctajoc, D.E. Breedlove & G. Davidse 54007 (CAS, MO); at Escopetazo, D.E. Breedlove & G. Davidse 53947 (CAS, MO). Jitotol: 10 km N of Jitotol, D.E. Breedlove 55152 (NY); near Colonia El Laurel, ca. 5 km N of Jitotol, G. Davidse et al. 29600 (MO). La Trinitaria: E.M. Martínez S. & W.D. Stevens 23903 (MEXU, MO). Paraje of Mahben Chauk, D.E. Breedlove 7677 (ENCB); Paraje of Yehts ‘Uk’um, D.E. Breedlove 7504 (ENCB); in the Paraje of Mahosik’, D.E. Breedlove 14861 (ENCB). cozingo: Estación Chajul, reserva Montes Azules, 4 km NE del poblado de Chajul, S. Sinaca-Colín s/n (MEXU). Tenejapa: In the Paraje of Mahosik’, A.S. Ton 1187 (ENCB). Tenejapa: Kulaktik, A.M. Ton 4570 (ENCB). San Juan Cancuc: El Pozo to Oxchuc, E. Hernández & Sharp X-616 ( US). Tenejapa: slopes, near Paraje Kulak’tik, D.E. Breedlove 53057 (CAS, MO); lopes west of Tih Ha’ in the Barrio of Kurus Pilal. Paraje of Mahben Chauk, D.E. Breedlove 6282 (DS). Zinacantán: from Zinacantán paraje of Paste’ to San Lucas, R.M. Laughlin 2583 (ENCB); ear Paraje Sequentic, D.E. Breedlove & G. Davidse 53910 (CAS, MO).

Figures

Figure 14. A-I Muhlenbergia mutica (Rupr. ex E. Fourn.) Hitchc. A habit B ligule C glumes D. lemma E stamens, pistil, and lodicules F inflorescence branch G glumes H lemma I stamens and lodicules. A-E drawn from P. M. Peterson & C. R. Annable 6051 (US) F-I drawn from Carl Mez Herbarium 3370 [Botteri & Sumichrast 104] (US- 1720166).