Bromus richardsonii Link. Atypical 1833

19. Bromusrichardsonii Link (1833: 281). Figs. 61, 62. Zerna richardsonii (Link) Nevski (1934: 17). Bromus ciliatus var. richardsonii (Link) Boivin (1967: 521). Zerna canadensis subsp. richardsonii (Link) Tzvelev (1971: 54). Bromopsis richardsonii (Link) Holub (1973: 168). Bromopsis canadensis subsp. richardsonii (Link) Tzvelev (1976: 214). Type:— Hab. in America septentrionali occidentali. Semina misit cl. Dr. Richardson [Grown in Berlin from seed provided by Dr. Richardson] (holotype B, destroyed fide Wagnon 1952). Bromus purgans var. longispicatus Hooker (1840: 252). Type:— CANADA. Rocky Mountains, T. Drummond s.n. (isotype USA865460! fragm.). Bromus mucroglumis Wagnon (1952: 67). Bromopsis mucroglumis (Wagnon) Holub (1973: 168). Type:— UNITED STATES OF AMERICA. Cultivated: grown in the greenhouse of the Botanical Garden, University of Michigan, from seed reproduced by the Soil Conservation Service (A-5712), Albuquerque, New México, and originally collected by Goodding, Locke, & Johnson at South Cave Creek, Chiricahua Mts., Cochise Co., Arizona, 28 July 1948, H.K. Wagnon 1520 (holotype MICH-1108614!, isotype US-2154824!). Bromus thysanoglottis Soderstrom & Beaman (1968: 509). Type:— MÉXICO. Durango: pine-oak region, Sierra Madre Occidental, Wof Ciudad Durango, 2 mi SW of Buenos Aires, 8800 ft, on precipitous slope, 8 September 1960, in clay soil, J.R. Reeder, C.G. Reeder & T.R. Soderstrom 3348 (holotype US-2457688!, isotypes ARIZ-246155!, ARIZ-226130!, YU-000863!). Plants perennial, not rhizomatous. Culms up to 120 cm tall, 1.5–6 mm wide at base, erect or ascending, sometimes decumbent at the base, glabrous below inflorescences; nodes 2–6, glabrous or pubescent. Leaf sheaths glabrous or pubescent to pilose, hairs sometimes restricted to distal sheath margins, hairs up to 1.5 mm long; auricles absent; ligules 0.6–3.3 mm long, glabrous or minutely pubescent, erose-lacerate; blades up to 38 cm × (3–)4–10.5(–13) mm, flat, glabrous or pubescent to pilose, hairs up to 1.5 mm long, margins smooth or serrulate. Panicles 12–35 cm × 2–17.5 cm, open, nodding, branches ascending to spreading or drooping, shorter or longer than spikelets, glabrous, scabrous or pubescent, 1–5 spikelets per branch. Spikelets 1.7–3.2(–3.6) cm long, 3–9(–12)-flowered, elliptic to lanceolate, terete to moderately laterally compressed, rachillas sometimes visible at maturity; glumes glabrous or minutely to strongly pubescent, hairs sometimes restricted to margins, hairs up to 1 mm long, margins hyaline, midnerves glabrous, scabrous or pubescent; lower glumes 5.5–9.5(–12) mm long, narrowly lanceolate to ovate–lanceolate, 1(–3)-nerved, green to purplish-green along and between the nerves; upper glumes (7–)8–12.5(–14.5) mm long, 3-nerved, obovate-lanceolate, green to purplish-green along and between the nerves, apices acute to mucronate, mucros 0.3–1.5(–2) mm long; lemmas (9–)10–13.5(–15) mm × 2–2.8 mm, elliptic to lanceolate, rounded over the backs, apices entire or minutely bifid, the cleft to 0.2 mm long, 7-nerved, green to purplish-green along and between the nerves, margins pubescent, hairs up to 1 mm long, backs glabrous or weakly to densely pubescent proximally and glabrous to scabridulous distally, hairs up to 0.7 mm long; awns 3.1–6.5 mm long, arising 0–0.5 mm below lemma apex, straight; paleas shorter and narrower than lemmas, backs glabrous or puberulent to pubescent, keels glabrous or ciliate, cilia up to 0.4 mm long; anthers 1–2.6(–3.4) mm long; caryopses 7−10 mm long. 2n = 28 (Mitchell & Wilton 1965, Armstrong 1983, Ward & Spellenberg 1988, Peterson et al. 2001). Distribution: ―Native. In México B. richardsonii is known from Baja California, Baja California Sur, Chihuahua, Durango, Coahuila, Michoácan, Nuevo León, Querétaro and Tlaxcala (Fig. 63). In North America, B. richardsonii is generally distributed west of the continental divide from the Yukon territory to central México, with disjunct populations known from the Cypress Hills in southern Alberta and Saskatchewan, the Black Hills in South Dakota and western Texas (Peterson et al. 2001, Pavlick & Anderton 2007). Ecology:— Steep to gentle slopes on rock outcrops or wooded habitats in granitic or calcareous soils, often in roadcuts, cliffs and arroyos; associated with Pinus durangensis, P. cooperi Blanco (1949: 185), P. jeffreyi, P. quadrifolia Parl. ex Sudworth (1897: 17), P. teocote, P. ayacahuite, Quercus arizonica Sargent (1895: 92), Q. durifolia Seemen in Loesener (1900: 95), Q. emoryi, Q. rugosa, Q. sideroxyla, A. concolor Lindl. ex Hildebrand (1861: 261), Pseudotsuga menziesii, Picea engelmannii, Cupressus arizonica, Juniperus deppeana, Arbutus arizonica, A. tessellata Sørensen (1987: 263), A. xalapensis, Holodiscus dumosus (S. Watson in Brewer 1876: 170) Heller (1898: 4), Arctostaphylos pungens, A. patula Greene (1891: 171), A. pringlei Parry (1887: 494), Populus tremuloides Michaux (1803b: 243), Platanus wrightii, Symphoricarpos oreophilus Gray (1873: 14), Alnus, Prunus serotina, Pachistima myrsinites, Garrya macrophylla, Cornus stolonifera, Ribes, Salvia, Heuchera Linnaeus (1753: 226), Lupinus, Senecio, Ceanothus, Baccharis, Brickellia Elliott (1824 [1823]: 290), Cercocarpus, Stevia Cavanilles (1797: 32), Geranium, Thalictrum, Pedicularis Linnaeus (1753: 607), Rubus, Sedum Linnaeus (1753: 430), Yucca Linnaeus (1753: 319), Physocarpus, Silene Linnaeus (1753: 416) and Cerastium Linnaeus (1753: 437). Elevation: 1500−3250 m. Espejo-Serna (2000) noted B. richardsonii (as B. ciliatus) to be introduced in México, which is incorrect. Common Name: ―Richardson’s brome (English). Comments: ―Plants treated here as B. richardsonii were recognized (in part, see discussion of B. mucroglumis below) as B. ciliatus in several Mexican treatments (Soderstrom & Beaman 1968, Beetle 1977, 1987, Gould & Moran 1981), while a more recent treatment recognized them as B. richardsonii (Herrera Arrieta 2001). The distinctions between B. ciliatus and B. richardsonii were, for a long time, unclear. Bromus richardsonii has been variously recognized as a distinct species (Shear 1900, Hitchcock 1913, Wagnon 1952, Kearney & Peebles 1960, Mitchell & Wilton 1965, Mitchell 1967, Hultén 1968, Welsh 1974, Pavlick 1995, Peterson et al. 2001, Saarela et al. 2005, Pavlick & Anderton 2007, Saarela 2008, Saarela & Peterson 2012) or as a synonym of B. ciliatus (Hitchcock 1951, Soderstrom & Beaman 1968, Allred 1993, Kartesz & Allen 1999, Espejo-Serna et al. 2000, Douglas et al. 2001, Hatch & Haile 2012). In a detailed study of the complex, Peterson et al. (2001) identified distinctive morphological, cytological and genetic differences that support recognition of these taxa as distinct species (also see Saarela 2008, Saarela & Peterson 2012). Bromus ciliatus is distributed across southern Canada and the United States, except south-central and southeastern U.S.A. (Pavlick & Anderton 2007); it is not known from México. Two collections from Municipio de Yécora, Sonora (Reina 98-1389A & Van Devender; Van Devender 98- 1590, Reina & Trauba) are unusual in having 3-nerved lower glumes and long awns (to 6.5 mm). Aspecimen from Volcán Tequila in Jalisco (Webster 15862, MICH) was treated as B. anomalus by McVaugh (1983), who noted this and another collection (Puga 6347, not seen) to be "robust, up to 1.2 m tall, with woolly sheaths and spikelets 2–4 cm long, suggesting in these characters B. lanatipes (Shear) Rydb., which has by some authors been treated as a variety of B. anomalus " (McVaugh 1983: 101). We treat this collection as B. richardsonii, along with others from Cerro Volcán (Peterson & Rosales 16061, 16067). Taxonomic Status of Bromus mucroglumis — Bromus mucroglumis was described from the Chiricahua Mts. in Arizona by Wagnon (1950), but has not generally been recognized until relatively recently, when it was resurrected by Beetle (1987) and Pavlick (1995) (Peterson et al. 2001). Bromus mucroglumis has since been reported from Colorado, southwestern New México, Arizona (San Francisco Mountains), Chihuahua, Sonora, Durango, Coahuila, Nuevo León and Baja California Sur (Beetle 1987, Pavlick 1995, Herrera Arrieta 2001, Peterson et al. 2001, Clayton et al. 2002 onwards, Pavlick & Anderton 2007, Shaw 2008). Bromus mucroglumis was included in B. richardsonii by Kearney & Peebles (1960), whereas Allred (1993) treated it as as a synonym of B. lanatipes in New México. Soderstrom & Beaman (1968) noted difficulties with the circumscription of B. mucroglumis. They found that several paratypes of B. mucroglumis represent multiple species, indicative of some confusion in the limits of the species when it was described by Wagnon (1950). We agree with Soderstrom & Beaman (1968), as did Gould & Moran (1981), that the paratype collections Carter et al. 2341 and Brandegee 73 are B. anomalus, and we recognize the paratype collection Pennell 1929 (GH!, US, not seen), which was treated as B. porteri by Soderstrom & Beaman (1968), as B. frondosus. We have not seen Le Sueur 092 (MO, US), which Soderstrom & Beaman (1968) recognized as B. thysanoglottis (see below for discussion of this taxon). Peterson et al. (2001) included four individuals of B. mucroglumis (three from Arizona, one from Chihuahua) in their taxonomic study of B. ciliatus and B. richardsonii. In a discriminant analysis, B. mucroglumis was wellseparated from the other taxa, the most important characters and states for its separation being lower glume length, lemma pubescence (hairs not restricted to margins) and adaxially hairy top culm blades. The four individuals of B. mucroglumis fell among the lower range of variation of B. richardsonii or were more or less intermediate between clusters of B. ciliatus and B. richardsonii in multiple bivariate comparisons of morphological and ecological (i.e., elevation) characters. The bivariate plots did not consider glume and lemma pubescence. Based on AFLP data, Peterson et al. (2001) found individuals of B. mucroglumis (all collected

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