Bromus tectorum Linnaeus 1753
Creators: name: Saarela, Jeffery M.
name: Peterson, Paul M.
name: Valdés-Reyna, Jesus
Publisher: name: Zenodo
Year: 2014
Subjects: Biodiversity
Taxonomy

description: 22. Bromus tectorum Linnaeus (1753: 77). Figs. 69, 70.
Schedonorus tectorum (L.) Fries (1843: 131). Genea tectorum (L.) Dumortier (1868: 67). Zerna tectorum (L.) Lindman (1918: 101). Anisantha tectorum (L.) Nevski (1934: 20, 22). Type:—EUROPE. Anon. (lectotype LINN- 93.23!, designated by Smith 1985: 500).
Bromus setaceus Buckley (1862: 98). Type:— UNITED STATES OF AMERICA. Texas: Buckley s.n. (holotype PH-01065439!, isotype US-865474! fragm. ex PH). Pavlick et al. (2003: 185) indicated the specimen fragment at US to be the lectotype, and noted " lectotype designated by Hitchcock, Man. Grass. U.S. 817 (1935), but without citing a specific sheet in a specific herbarium." Buckley's original material is in PH and the specimen there is the holotype; the US specimen fragment is an isotype.
Plants annual. Culms 5–80 cm tall, 0.7–2.5 mm wide at base, solitary or loosely tufted, erect or ascending, weakly to moderately pubescent below inflorescences; nodes 2–4, glabrous or minutely pubescent. Leaf sheaths glabrous or variously pubescent, hairs stiff and up to 0.5 mm, or soft, wavy and up to 1 mm long, longer hairs up to 2 mm long sometimes present towards sheath apex; auricles absent; ligules (1–) 2–3 mm long, glabrous, erose-lacerate; blades 1.3–14 cm × 1–5 mm, flat, adaxial surface sparsely to densely pubescent, hairs stiff hairs and up to 0.3 mm long, abaxial surface puberulent, hairs appressed and ca. 0.1 mm long, sometimes denser towards blade apex, margins smooth or with hairs like adaxial leaf surface. Panicles 4–22 cm × 1–13.5 cm, condensed and erect when young, becoming lax and nodding, sometimes reduced to a few spikelets, branches spreading to drooping, 0.4–4 cm long, usually longer than spikelets, usually one-sided, often sinuous, scabrous to densely pubescent, 1–14 spikelets per branch. Spikelets 1.5–2(–2.5) cm long (2.5–3.5 cm including awns), 3–6(–8)-flowered, linear-elliptic to cuneate, sometimes broadening at maturity, moderately laterally compressed, rachillas sometimes visible at maturity; glumes glabrous or minutely to densely pubescent with short, appressed hairs, with occasional long, soft hairs up to 1 mm long, these sometimes occurring in a line just inside margins, margins hyaline, midnerves glabrous or scabrous, apices ± bifid, the cleft 0.1–0.5 mm deep; lower glumes 4–9 mm long, linear-lanceolate, 1(–3)-nerved, green to purplish-green along and between the nerves, occasionally minutely awned, awn to 1.1 mm long; upper glumes 7–13.5 mm long, elliptic-lanceolate, 3(–5)-nerved, green to purplish-green along and between the nerves; lemmas 9–13.8 mm × (0.6–) 0.9–1.5 mm, lanceolate, rounded over the backs, apices bifid, the teeth 1–3
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Phytotaxa 185 (1) © 2014 Magnolia Press 129 mm long, 7-nerved, green to purplish-green along and between the nerves, backs glabrous, scabrous, or pubescent with long, soft hairs up to 1 mm long, hairs sometimes denser along margins and sometimes present only on upper two thirds, nerves smooth or scabrous; awns 8–18 mm long, arising 1.1–2.7 mm below lemma apex, straight; paleas 7–8.7 mm long, shorter and narrower than the lemmas, backs glabrous, translucent, keels ciliate, cilia up to 0.6 mm long; anthers 0.5–0.9 mm long; caryopses 7−8 mm long. 2 n = 14 (Sharma & Sharma 1979, Ward 1983, Lövkvist & Hultgård 1999).
Distribution: —Introduced. In México, B. tectorum occurs in northern Baja California (Fig. 71). Collections have also been made in Chihuahua and Coahuila, but it is not known if the species persists in these areas.
Ecology: — Bromus tectorum is found on slopes, arroyos and meadows; associated with Pinus jeffreyi, Abies concolor, Arctostaphylos patula, A. pringlei, Holodiscus dumosus, Symphoricarpos oreophilus and Populus tremuloides. Elevation: 930–2830 m.
Common Names: —cheatgrass, cheat grass, downy brome, drooping brome, early chess, military grass, thatch bromegrass (English).
Comments: —Glabrous plants are sometimes recognized as B. tectorum var. glabratus Spenner (1825: 152) (Gould & Moran 1981, Beetle 1987). Bromus tectorum is a serious invasive weed. In North America north of México the first specimen was collected in 1859 in Pennsylvania, and the first report in western North America is from Spence’s Bridge, British Columbia, where the species was collected in 1889 (Mack 1981). Acollection from Guadalupe Island, Baja California, in 1875 (Palmer 99, NY!) is the earliest report in North America (Novak & Mack 2001). Multiple introductions of B. tectorum into North America have been documented with genetic data (e.g., Mack 1981, Novak et al. 1991, Novak & Mack 1993, Novak & Mack 2001, Bartlett et al. 2002, Valliant et al. 2007, Schachner et al. 2008). The species is used as fodder (Saulés & Dávila Aranda 1992). Bromus tectorum was not reported for Mexico by Soderstrom & Beaman (1968).
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Specimens Examined:— MÉXICO. Baja California: Guadalupe Island, [29.04°N, 118.28°W], 1875, E. Palmer 99 (NY, mixed sheet with B. berteroanus); 0–3 mi beyond end of road into Nend of high Sierra San Pedro Mártir, [31.0372°N, 115.4542°W], 7200–7700 ft [2195–2347 m], 6 July 1962, J. D. Olmsted 4589 (RSA-POM- 170824); 1 km Wof El Retiro and 11 km SSW of La Rumorosa, 32.4583°N, 116.1°W, 1275 m, 9 May 1982, R. Moran 30660 (SD-111159); 2.5 km Sof El Condor, 32.4417°N, 116.1583°W, 1300 m, 26 May 1979, R. Moran 27335 (SD-103403); 4 km SE of San Valentín, Eof Tecate, 32.5458°N, 116.425°W, 940 m, 11 May 1980, R. Moran 28530 (SD-105869); 5 km Sof Los Gavilanes, 32.2°N, 116.0042°W, 1675 m, 28 May 1979, R. Moran 27502 (SD-104027); 6 km SE of San Pedro, 32.1417°N, 115.9375°W, 1680 m, 28 May 1979, R. Moran 27510 (SD-104029); arroyo bed just Sof Rancho San Faustino, 32.2167°N, 116.1667°W, 1290 m, 27 June 1981, R. Moran 29637 (SD-108489); Cerro La Parra, 31.7667°N, 115.7833°W, 1775 m, 31 July 1976, R. Moran 23660 (SD- 94644); edge of Río San Rafael, NW end of Sierra San Pedro Mártir, [31.15°N, 115.45°W], 4500 ft [1372 m], 6 August 1962, J. D. Olmsted 4664 (RSA-POM-170690); El Rayo, sobre la brecha a la Laguna de Hanson, al ENE de Ensenada, [32.0542°N, 115.075°W], 1 May 1981, R. Guzmán 1330 (MEXU); Ensenada, [31.87°N, 116.59°W], 27 May 1993, Jaramillo V., Villegas G., Domínguez O. et al. 81 (MEXU); Ex-Misión San Pedro Mártir, 30.8°N, 115.45°W, 1475 m, 1 June 1975, R. Moran 22124 (SD-91433); in meadow NW of Rancho Pantalones, 4 km NNW of Laguna Hanson, 32.1042°N, 115.9208°W, 1650 m, 24 June 1979, R. Moran 27693 (SD-103013); La Grulla, 30.8917°N, 115.4833°W, 2050 m, 8 June 1982, R. Moran 30916 (SD-111214); Metamorphics 4 km SE of El Topo, 32.2167°N, 115.95°W, 1690 m, 16 May 1982, R. Moran 30759 (SD-110998); Mpio. Ensenada, Ahuaje El Sapo Ejido Sierra de Juárez, 2531 pies, [32.29°N, 115.86°W], 13 May 1997, A. Miranda S. 1151 (MEXU); Mpio. Ensenada, Rancho San Faustino, [32.22°N, 116.17°W], 3 May 1981, R. Guzmán M. 1373 (MEXU-1098061); Mpio. Ensenada, Sierra de Juárez aserradero cerca de la Laguna Hanson en el Parque Nacional Constitución de 1917, [31.97°N, 115.84°W], 1500 m, 30 April 1994, V. Jaramillo V., G. Villegas & A. Miranda 953 (MEXU); Mpio. Ensenada, Rancho La Concepción, 33 km al SW de el Observatorio San Pedro Mártir, 31.05°N, 115.6167°W, 1300 m, 30 April 1987, P. Tenorio L. & C. Romero T. 13183 (MEXU-995769, MEXU-1098042); Mpio. Mexicali, Ejido Jacumé km 78 carretera Mexicali-Tijuana, [32.47°N, 116.18°W], 1260 m, 12 May 1997, M. A. Vergara B. 82 (MEXU-1098070); Mpio. Tecate, Santa Verónica, [32.46°N, 116.36°W], 930 m, 26 May 1993, Jaramillo V., Villegas G. & Domínguez O. 17 (MEXU-1098067); Mpio. Tijuana, La Rumorosa, [32.535°N, 116.05°W], 1220 m, 17 May 1987, P. Tenorio L. & C. Romero de T. 13459 (MEXU); near summit of Cerro de la Cupula (= C.2828), 31.0333°N, 115.45°W, 2800 m, 2 July 1982, R. Moran 30981 (SD-127299); near summit of Cerro de la Cupula (C. 2828), 31.0333°N, 115.45°W, 2700 m, 27 July 1970, R. Moran 17893 (SD-76453); Parque Nacional Constitución, Laguna Hanson, [32.0542°N, 115.075°W], 1 May 1981, A. A. Beetle & R. Alcarez M-6641 (ANSM, MICH-119287, MEXU-1098069); Parque Nacional Constitución, Laguna Hanson, Sierra de Juárez, [32.07°N, 115.89°W], ca. 1610 m, 15 September 1983, R. F. Thorne, K. Kubitzki, P. Peterson & C. Annable 57061 (RSA-POM-332659); Parque Nacional Constitución, Laguna Hanson, Sierra de Juárez, [31.97°N, 115.84°W], 1610–1625 m, 28 May 1983, R. F. Thorne, W. Wisura, W. Steinmetz et al. 55773 (RSA-POM-310447, SD-123838); Sof El Condor, 0.5–2.3 miS, [32.45°N, 115.95°W], 1300 m, 9 May 1985, R. F. Thorne & W. Wisura 60554 (RSA-POM-342697); Wshore of Laguna Hanson, 32.0542°N, 115.075°W, 1610 m, 21 June 1980, R. Moran 28865 (SD-105484); Sierra San Pedro Mártir, Rancho Meling, [31.0372°N, 115.4542°W], 940 m, 27 May 1993, Jaramillo V., Villegas G., O. Domínguez et al. 65 (MEXU); Sierra San Pedro Mártir, above Yerba Buena, 31.0333°N, 115.45°W, 2750 m, 30 May 1977, Reid Moran 24206 (MEXU-726456); Sierra San Pedro Mártir, Corral Meadow, 7.5 km NW of the observatory, 31.1125°N, 115.4972°W, 2520 m, 26 June 1988, A. C. Sanders, R. Minnich, E. Franco & M. Salazar 7922 (RSA-POM-474990, SD-125856); Sierra San Pedro Mártir, La Concepción, 31.0167°N, 115.6167°W, 1600 m, 31 May 1968, R. Moran 15003 (SD-69303, US); Sierra San Pedro Mártir, La Concepcion, 31.0167°N, 115.6167°W, 1600 m, 31 May 1968, R. Moran 15004 (SD-69302); Sierra San Pedro Mártir, Oak Pasture, 30.9583°N, 115.6°W, 1710 m, 8 May 1978, R. Moran 25688 (SD-100727); Sierra San Pedro Mártir, Sof Vallecitos near Cerro la Botella Azul, [30.9556°N, 115.4239°W], 2440 m, 27 June 1998, J. Rebman & A. Russell 5389 (ASU- 0010744, RSA-POM-642764, SD-145344); Sierra San Pedro Mártir, Yerba Buena, [31.0333°N, 115.3°W], 2450 m, 16 August 1967, R. Moran & R. F. Thorne 14235 (RSA-POM-222143); Sierra San Pedro Mártir, Vallecitos, [30.9556°N, 115.4239°W], 17 October 1982, M. del Real M. 301 (MEXU-1098065); Parque Nacional San Pedro Mártir, 5.1 km Eof Wpark entrance, [31.0372°N, 115.4542°W], 2470 m, 27 August 1988, P. M. Peterson, C. R. Annable, R. F. Thorne & R. D. Noyes 5106 (CAN, US); Sierra San Pedro Mártir, [31.0372°N, 115.4542°W], 7 May 1991, O. Paullin & M. Montoya 265 (MEXU-1098064); Sierra San Pedro Mártir, Cerro Observatorio, [31.0372°N,
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115.4542°W], 2830 m, 28 August 1988, P. M. Peterson, C. R. Annable, R. F. Thorne & R. D. Noyes 05246 (US); Sierra San Pedro Mártir, 55 mi SE of Hwy. 1 on road towards Villecentos at Arroyo Los Alamillos, 31.0112°N, 115.54°W, 2270 m, 24 September 2000, P. M. Peterson & J. Cayouette 15184 (US); Sierra San Pedro Mártir, Vallecitos Meadow, 16.6 km Eof Wpark entrance, [31.0372°N, 115.4542°W], 2485 m, 27 August 1988, P. M. Peterson, C. R. Annable, R. F. Thorne & R. D. Noyes 5112 (CAN, US); Sierra San Pedro Mártir, camp site at Vallecitos, [31.0333°N, 115.3°W], 8300 ft [2530 m], 19 September 1983, P. M. Peterson, C. R. Annable, R. F. Thorne & K. Kubitzki 1932 (US); Sierra San Pedro Mártir, 56 mi SE of Hwy. 1 on road towards Villecentos, 31.0157°N, 115.53°W, 2210 m, 24 September 2000, P. M. Peterson & J. Cayouette 15192 (US); upper (E) end of Vallecitos Meadow, 31°N, 115.45°W, 2350 m, 6 September 1976, R. Moran 23735 (SD-94746); Vallecitos, near road to observatory and campground, [31.0333°N, 115.3°W], 2430 m, 18 June 1985, R. F. Thorne, R. Dahlgren, S. Boyd & D. Charlton 60840 (RSA-POM-346117); 10.5 mi Wof La Rumorosa, along Hwy. 2, [32.51°N, 116.13°W], 1310 m, 8 May 1985, R. F. Thorne & W. Wisura 60425 (RSA-POM-342669); YerbaBuena, 31°N, 115.45°W, 2450 m, 16 August 1967, R. Moran & R. F. Thorne 14235 (SD-76628); YerbaBuena, 31.0333°N, 115.45°W, 2750 m, 30 May 1977, R. Moran 24206 (SD-98077). Chihuahua: Maleza en Jardín de observacion en La Campana, [28.63°N, 106.08°W], 12 April 1975, J. Valdés-Reyna VR 877 (ANSM). Coahuila: Buenavista, 25.4333°N, 101.1°W, 1600 m, s.d., A. de los Reyes s.n. (ANSM). Sonora: El Papalote, 18 km on MEX Hwy. 2, Wof Sonoyta, [31.1675°N, 112.9933°W], 9 April 1986, R. S. Felger & R. Valenzuela López 86-133 (ARIZ-263959).
Excluded Taxa
Bromus arenarius Labillardière (1804 [1805]: 23, pl. 28)
Wiggins (1980) reported B. arenarius from northern Baja California. Gould & Moran (1981) noted that they did not see specimens of this species and did not treat it, whereas Beetle (1987) later treated it for Baja California. We have not seen any specimens of this species from México.
Bromus ciliatus L.
See comments under B. richardsonii.
Bromus commutatus Schrader (1806: 353)
Beetle (1987) noted that B. commutatus has been collected in Chihuahua, but is not established there. His report may be based on MEXU-243518 collected 26 August 1978 at Rancho Experimental La Campana (there is no
ATAXONOMIC REVISION OF BROMUS (POACEAE)
Phytotaxa 185 (1) © 2014 Magnolia Press 133 collector given on the specimen label) and originally determined as B. commutatus; the specimen is B. japonicus. This species was again reported recently from the same experimental station by Royo Márquez & Melgoza Castillo (2012), likely based on the same mis-identified specimen.
Bromus grandis (Shear 1900: 243) Hitchcock in Jepson (1912: 175)
Wiggins (1980) reported this taxon from N Sierra Juárez, Baja California. Gould & Moran (1981) noted that they did not see specimens of this taxon and did not treat it. We have not seen specimens of this taxon from Baja California or elsewhere in México.
Bromus orcuttianus Vasey (1885a: 223)
Wiggins (1980: 912) reported this taxon from "northernmost Baja California ". Gould & Moran (1981) noted that they did not see specimens of this taxon and did not treat it. We have not seen specimens of this taxon from Baja California or elsewhere in México. Aspecimen determined originally as B. orcuttianus from southwestern Chihuahua (Aug–November 1883, Palmer 233, NY!) is a species of Brachypodium. Another specimen from Chihuahua (Jones s.n., RSA-POM), incorrectly determined as B. orcuttianus, is B. carinatus var. marginatus.
Bromus porteri (Coulter 1885: 425) Nash (1895: 512)
See comments under B. anomalus.
Bromus sterilis Linnaeus (1753: 77)
Espejo-Serna et al. (2000) reported B. sterilis from Baja California. This report may be based on Paulin & Morales 218 (MEXU-1098059) and MEXU-109768, both collected in Baja California and originally determined as B. sterilis; the former specimen is B. carinatus, the latter is B. madritensis.
Bromus texensis (Shear 1900: 41) Hitchcock (1913: 381)
Reported from México by Hitchcock (1913), on the basis of a specimen in US (Pringle 2052). Wagnon (1952) noted that this specimen is B. anomalus, a determination with which we agree.
description: Published as part of Saarela, Jeffery M., Peterson, Paul M. & Valdés-Reyna, Jesus, 2014, A taxonomic revision of Bromus (Poaceae: Pooideae: Bromeae) in México and Central America, pp. 1-147 in Phytotaxa 185 (1) on pages 129-134, DOI: 10.11646/phytotaxa.185.1.1, http://zenodo.org/record/10090001