Muhlenbergia Schreb., Gen. Pl. 1: 44. 1789.

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

Muhlenbergia Schreb., Gen. Pl. 1: 44. 1789.

Dilepyrum Michx., Fl. Bor.-Amer. 1: 40. 1803. Type: Dilepyrum minutiflorum Michx. (= Muhlenbergia schreberi J. F. Gmel.). ( M. subg. Muhlenbergia ).

Aegopogon Humb. & Bonpl. ex Willd., Sp. Pl. 4 (2): 899. 1805 [1806]. Type: Aegopogon cenchroides Humb. & Bonpl. ex Willd. [≡ Muhlenbergia cenchroides (Humb. & Bonpl. ex Willd.) P.M. Peterson]. ( M. subg. Muhlenbergia ).

Podosemum Desv., Nouv. Bull. Sci. Soc. Philom. Paris 2: 188. 1810. Type: Podosemum capillare (Lam.) Desv. [≡ Muhlenbergia capillaris (Lam.) Trin.]. ( M. subg. Trichochloa ).

Clomena P. Beauv., Ess. Agrostogr. 28. 1812. Type: Clomena peruviana P. Beauv. [≡ Muhlenbergia peruviana (P. Beauv.) Steud.]. ( M. subg. Clomena ).

Tosagris P. Beauv., Ess. Agrostogr. 29. 1812. Type: Tosagris agrostidea P. Beauv. [= Muhlenbergia capillaris (Lam.) Trin.]. ( M. subg. Trichochloa ).

Trichochloa P. Beauv., Ess. Agrostogr. 29. 1812. Type: Trichochloa purpurea P. Beauv. [= Muhlenbergia expansa (Poir.) Trin.]. ( M. subg. Trichochloa ).

Podosaemum Kunth, Mem. Mus. Hist. Nat. 2: 72. 1815; orth. var. Muhlenbergia purpurea Podosemum . ( M. subg. Trichochloa ).

Hymenothecium Lag., Gen. Sp. Pl. 4. 1816. Lectotype: Cynosurus tenellus Cav. ex DC., designated by Hitchcock 1920: 169 [≡ Lamarckia tenella DC. ≡ Hymenothecium tenellum (Cav. ex DC.) Lag. = Muhlenbergia uniseta (Lag.) Columbus]. ( M. subg. Muhlenbergia ).

Lycurus Kunth, Nov. Gen. Sp. 1: 141. 1815 [1816]. Lectotype: Lycurus phleoides Kunth, designated by Hitchcock 1920: 139 [≡ Muhlenbergia phleoides (Kunth) Columbus]. ( M. subg. Pseudosporobolus ).

Anthipsimus Raf., J. Phys. Chim. Hist. Nat. Arts 89: 105. 1819. Type: Anthipsimus gonopodus Raf. (= Muhlenbergia schreberi J.F. Gmel.). ( M. subg. Muhlenbergia ).

Sericrostis Raf., Neogenyton 4. 1825. Lectotype: Stipa sericea Michx, designated by Pfeiffer 1874: 1142 [≡ Muhlenbergia sericea (Michx.) P.M. Peterson]. ( M. subg. Trichochloa ).

Pereilema J. Presl, Reliq. Haenk. 1 (4-5): 233.1830. Type: Pereilema crinitum J. Presl (≡ Muhlenbergia pereilema P.M. Peterson). ( M. subg. Muhlenbergia ).

Epicampes J. Presl, Reliq. Haenk. 1 (4-5): 235. 1830. Type: Epicampes stricta J. Presl [= Muhlenbergia robusta (E. Fourn.) Hitchc.]. ( M. subg. Trichochloa ).

Dactylogramma Link, Hort. Berol. 2: 248. 1833. Type: Dactylogramma cinnoides Link [= Muhlenbergia glomerata (Willd.) Trin.]. ( M. subg. Muhlenbergia ).

Calycodon Nutt., Proc. Acad. Nat. Sci. Philadelphia 4: 23. 1848. Type: Calycodon montanum Nutt. [≡ Muhlenbergia montana (Nutt.) Hitchc.]. ( M. subg. Clomena ).

Pleopogon Nutt., Proc. Acad. Nat. Sci. Philadelphia 4: 25. 1848. Type: Pleopogon setosum Nutt. [≡ Lycurus setosus (Nutt.) C.G. Reeder = Muhlenbergia alopecuroides (Griseb.) P.M. Peterson & Columbus]. ( M. subg. Pseudosporobolus ).

Schedonnardus Steud., Syn. Pl. Glumac. 1: 146. 1854. Type: Schedonnardus texanus Steud. [= Lepturus paniculatus Nutt. ≡ Rottboellia paniculata (Nutt.) Spreng. ≡ Schedonnardus paniculatus (Nutt.) Branner & Coville ≡ Spirochloe paniculata (Nutt.) Lunell ≡ Muhlenbergia paniculata (Nutt.) Columbus]. ( M. subg. Pseudosporobolus ).

Vaseya Thurb., Proc. Acad. Nat. Sci. Philadelphia 15: 79. 1863. Type: Vaseya comata Thurb. [= Muhlenbergia andina (Nutt.) Hitchc.]. ( M. subg. Muhlenbergia ).

Chaboissaea E. Fourn., Mexic. Pl. 2: 112. 1886. Type: Chaboissaea ligulata E. Fourn. [≡ Muhlenbergia ligulata (E. Fourn.) Scribn. & Merr.]. ( M. subg. Pseudosporobolus ).

Crypsinna E. Fourn., Mexic. Pl. 2: 90. 1886. Lectotype: Crypsis macroura Kunth, designated by Hitchcock 1920: 144. [≡ Crypsinna macroura (Kunth) E. Fourn.≡ Muhlenbergia macroura (Kunth) Hitchc.]. ( M. subg. Trichochloa ).

Redfieldia Vasey, Bull. Torrey Bot. Club 14: 133. 1887. Type: Graphephorum flexuosum Thurb. ex A. Gray [≡ Redfieldia flexuosa (Thurb. ex A. Gray) Vasey ≡ Muhlenbergia multiflora Columbus]. ( M. subg. Pseudosporobolus ).

Bealia Scribn., True Grasses 104, f. 45a. 1890. Type: Bealia mexicana Scribn. (≡ Muhlenbergia biloba Hitchc.). ( M. subg. Bealia ).

Blepharoneuron Nash, Bull. Torrey Bot. Club 25(2): 88. 1898. Lectotype: Vilfa tricholepis Torr., designated by Peterson and Annable 1990: 522 [≡ Blepharoneuron tricholepis (Torr.) Nash ≡ Muhlenbergia tricholepis (Torr.) Columbus]. ( M. subg. Bealia )

Schaffnerella Nash, N. Amer. Fl. 17(2): 141. 1912. Type: Schaffnera gracilis Benth. [≡ Schaffnerella gracilis (Benth.) Nash ≡ Muhlenbergia spatha Columbus]. ( M. subg. Pseudosporobolus ).

Description.

Plants annual or perennial; usually synoecious, infrequently andromonoecious; sometimes rhizomatous, often cespitose, sometimes mat-forming, rarely stoloniferous. Culms 2-300 cm, erect, geniculate, or decumbent, usually herbaceous, sometimes becoming woody. Sheaths open; ligules membranous or hyaline (rarely firm or coriaceous), acuminate to truncate, sometimes minutely ciliolate, sometimes with lateral lobes longer than the central portion; blades narrow, flat, folded, or involute, sometimes arcuate. Inflorescences (synflorescence) terminal, sometimes also axillary, open to contracted, racemelike or spikelike panicles; disarticulation usually above the glumes, occasionally below the pedicels. Spikelets mostly perfect with 1 (2-6) florets, sometimes staminate or sterile, occasionally paired or in groups of threes then the central spikelet perfect and the lateral ones staminate or sterile; chasmogamous, rarely cleistogamous; glumes usually (0)1(2-3)-veined, apices entire, erose, or toothed, truncate to acuminate, sometimes mucronate or awned from the midvein, occasionally awned from the lateral veins; lower glumes sometimes rudimentary or absent, occasionally bifid; upper glumes shorter than to longer than the florets; callus es poorly developed, glabrous or hairy, the hairs up to 3.5 mm long, straight; lemmas glabrous, scabrous, or with short hairs, 3-veined (rarely appearing 5-veined), apices awned from the midvein, mucronate, or unawned; awns, if present, straight, flexuous, sinuous, or curled, sometimes borne between 2 minute teeth, lateral veins occasionally extended into awns; paleas shorter than or equal to the lemmas, 2-veined, apices; lodicules 2, cuneate, fleshy, sometimes with a narrow membranous apex, apex truncate and slightly lobed, glabrous; anthers (1-2) 3, purple, orange, yellow, olivaceous, or whitish; ovary with 2 styles (rarely 1), glabrous, stigmas plumose. Caryopses an achene,elongate, fusiform or elliptic, slightly dorsally compressed, rarely laterally compressed, free threshing; grain solid without lipid. Cleistogamous panicles sometimes present in the axils of the lower cauline leaves, enclosed by a tightly rolled, somewhat indurate sheath. Chromosome base number is x = (8 or 9) 10, and these are relatively small in size when compared to chromosomes in the Pooideae .

Distribution.

The genus is primarily distributed in the Western Hemisphere in North, Central, and South America ( Peterson 2003; Peterson and Giraldo-Cañas 2012; Peterson et al. 2018, 2021). There are also eight species known to occur in southeastern Asia; six of these are found in China ( Wu and Peterson 2006) and five in India ( Tiwari et al. 2023).

Ecology.

The species occur in open habitats in deserts, grasslands, sclerophyllous scrubland, and margins of forests often in xeric to meso-xeric habitats from near sea level to more than 4000 m.

Etymology.

Named for Gotthilf Henry Ernest Muhlenberg (1753-1815), a Lutheran minister and pioneer botanist of Pennsylvania, USA.