3urn:lsid:arphahub.com:pub:F7FCE910-8E78-573F-9C77-7788555F8AADPhytoKeysPK1314-20111314-2003Pensoft Publishers10.3897/phytokeys.121.3258832588Research ArticlePoaceaeTaxonomyEuropeA new species of perennial Bromus (Bromeae, Poaceae) from the Iberian PeninsulaAcedoCarmenc.acedo@unileon.eshttps://orcid.org/0000-0001-6692-65091LlamasFélixhttps://orcid.org/0000-0002-2218-896X1Research Group Taxonomy and Conservation of Biodiversity TaCoBi, Department of Biodiversity and Environment Management, University of León, E-24071. León, SpainUniversity of LeónLeónSpain
Corresponding author: Carmen Acedo (c.acedo@unileon.es)
Academic editor: M. Vorontsova
2019240420191211121E64FFC7-F707-733F-FFD4-FFB6FFF0603426568242012201822032019Carmen Acedo, Félix LlamasThis is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
During a survey of the genus Bromus for the ongoing Flora Iberica, B.picoeuropeanussp. nov., a new orophilous species of perennial Bromus from Picos de Europa National Park, was found, and it is described and illustrated here. This new species belongs to the Bromuserectus complex and differs from the other perennial species of this group occurring in the Iberian Peninsula in its well-developed rhizome, the small innovation leaves and all peduncles and branches shorter than the spikelets. B.picoeuropeanus grows on calcareous stony soils associated with dry places. We provide a description and illustrations of the new species and an identification key for the most related European perennial species belonging to the complex.
BromeaBromussubg.FestucoidesBromuserectus complexBromuspicoeuropeanusCantabrian rangeIdentification KeyNew speciesPoaceaeSpainTaxonomyMinisterio de Economía y Competitividad501100003329http://doi.org/10.13039/501100003329Ministerio de Ciencia e Innovación501100004837http://doi.org/10.13039/501100004837Citation
Acedo C, Llamas F (2019) A new species of perennial Bromus (Bromeae, Poaceae) from the Iberian Peninsula. PhytoKeys 121: 1–12. https://doi.org/10.3897/phytokeys.121.32588
Introduction
The genus Bromus L. is the only representative of the tribe Bromeae in Southwest Europe. The genus comprises perennial and annual species, and both life forms are distributed throughout the genus. Bromus has a characteristic fleshy appendage above the style insertion, which is pubescent at its apex and persistent in the caryopsis. The taxonomy of this genus is considered troublesome and has been the subject of numerous regional taxonomic revisions (e.g. Smith and Sales 1993; Acedo and Llamas 1999; Saarela 2008), and the main subject of several studies (e.g. Smith 1972; Acedo and Llamas 2001; Saarela et al. 2007; Oja and Zimmermann 2010; Alonso et al. 2014; Alonso 2015). It includes more than 170 species mainly in the Northern hemisphere (Acedo and Llamas 2001; Saarela et al. 2014).
The last revision of the genus Bromus L. in the Iberian Peninsula (Acedo and Llamas 1999) included a detailed discussion of its taxonomic history, morphology, anatomy, distribution and other relevant information for the region. Some twenty-five species of Bromus occur in the Iberian Peninsula. The Iberian monograph includes only two alien species, B.catharticus Vahl and B.inermis Leyss., and recently another weedy species was found: B.sitchensis Trin. (Acedo, unpublished data), native to northwestern North America. Some taxonomic studies (Oganesian 2004; Tzvelev 1976), the Euro+Med List of Plants (Valdés and Scholz 2006; 2009) or the Flora of Italy (Pignatti et al. 2017), and Flora of Russia (Fedorov 1999) treated the Old World perennial Bromus at the generic level as Bromopsis (Dumort.) Fourr. However, other authors argue it must be treated as Bromussect.Bromopsis Dumort. (Saarela 2008; Naderi and Rahiminejad 2015: 243) or subgenus Festucoides (Stebbins 1981; Acedo and Llamas 1999; Alonso, Llamas, Pimentel, and Acedo unpublished data) based on karyological and morphological data, and phylogenetic relationships suggested by molecular nuclear and plastid data regions. This study follows the proposal to split the genus Bromus into subgenera.
The European perennials belong to Bromussubg.Festucoides (Coss. & Durieu) Hackel, which is not monophyletic in its current circumscription (Saarela et al. 2007; Alonso 2015). It comprises between sixty and seventy perennial species, including caespitose or rhizomatous plants, ranging in height from twenty to more than one hundred and fifty centimeters, and growing in diverse terrestrial habitats such as forest, hedges and pastures, etc. In Europe, only a few species are associated with temperate forests (Smith 1981; Acedo and Llamas 1999). In this subgenus, the cross-section of the leaf blade is characterized by soft ribs and numerous primary vascular bundles bound by wide and complete sclerenchyma beams. The narrow spikelets with close parallel sides have glumes which are 1–3(5)-nerved (Acedo and Llamas 1999). The presence or absence of a developed long rhizome is considered an important diagnostic character within the perennial Bromus. Its presence is diagnostic for several European and West Asian species of Bromus as several authors pointed out in their identification keys (i.e. Tzvelev 1976; Smith 1980; Pignatti et al. 2017). In addition, the presence of a developed rhizome and the presence of tuberous basal internodes are diagnostic in North African taxa belonging to this group (Maire et al. 1955). Several European perennial taxa are caespitose and lack rhizomes (Smith 1980; Pignatti et al. 2017). The European perennials form a morphologically heterogeneous group, including taxa with broad distributions as well as narrow endemisms that are grouped within several complexes of cytologically and morphologically similar species (e.g. the Bromuserectus complex and the Bromusramosus complex). The Bromuserectus complex includes perennial species, with old sheaths remaining intact or decaying into parallel fibres, inflorescences with some long branches and/or pedicels, and spikelets erect (Smith 1980, Acedo et al. 2009; Pignatti et al. 2017). The taxonomy of some species or groups was studied in different regions e.g. “Bromuserectus Group” in Slovenia (Bačič and Jogan 2001) or the species B.erectus along the Cantabrian range and Pyrenean mountains in the Iberian Peninsula (Acedo et al. 2009). The Bromuserectus complex includes several endemics and probably some taxa remain undescribed, due to the lack of a global taxonomic revision.
The main objectives of this study are to describe a new species, to differentiate it from its relatives, and to characterize this new taxon.
Materials and methods
Several specimens of perennial Bromus were collected during a survey of the genus Bromus for the ongoing Flora Iberica project. This material was confirmed as a new species after a careful study and comparison with material deposited at JBAG, LEB, FCO, MA, MAF, JACA, SALA, SANT, VIT, representing the full distribution and variability of B.erectus Huds. from the Iberian Peninsula as well as specimens belonging to related species (B.condensatus Steud., B.stenophyllus Link, B.transsilvanicus Steud.) and other perennial European species (B.biebersteinii Roem. & Schult., B.moellendorffianus (Asch. & Graebn.) Hayek, B.moesiacus Velen., B.pannonicus Kumm. & Sendtn., B.riparius Rhemann, B.tomentellus Boiss.). In addition, material from several important European Herbaria: C, K, FI, MSNM was studied. We also studied specimens and photographs of types and original material in B, P, and K, including the type specimen of B.erectus (Llamas and Acedo 2019, in press). Herbarium acronyms follow Thiers (2018+ continuously updated).
Specimen locality data were recorded in the field or via geo-referencing. We assessed the preliminary conservation status of the new species using our field knowledge, applying the IUCN (2017) criteria and performing a GeoCat analysis (Bachman et al. 2011). The extent of occurrence (EOO) and the area of occupancy (AOO) were estimated using GeoCat. For AOO calculation, a 2 km cell width was used. The information and measurements of the new and closely related species were taken from live and dried herbarium specimens, and from field data. The taxonomic treatment of the genus Bromus follows Acedo and Llamas (1999). Measurements and data for the diagnostic characters comparing the new species and B.erectus are presented in Table 1, and an identification key is provided to facilitate differentiation from the related European species.
Summary of the main taxonomic traits that differentiate Bromuspicoeuropeanus Acedo & Llamas from B.erectus Huds.
B.picoeuropeanus Acedo & Llamas
B.erectus Huds.
Habit
Loosely tufted
Densely caespitose
Rhizome presence
Rhizomatous
None, or inconspicuous rhizome, caespitose
Height
Up to 40 cm
60–130 cm
Basal and cauline leaf blade
Flat, basal similar to the cauline, 2–3.5 mm wide
The basal narrower (c.1 mm) and longer than cauline (2–3 mm wide)
Spain. Cantabria: Macizo Oriental de Picos de Europa, Vegas de Ándara: Fuente de la Escalera. 43°12.42'N, 4°42.20'W, [WGS-84], on limestone dry rocky sites, moving by gelifraction, 1869 m alt., 31 August 2011; C. Acedo, A. Alonso & F. Llamas CA247.4 (Holotype LEB 121814).
Diagnosis.
Bromuspicoeuropeanus differs from B.erectus Huds. (Table 1) in having shorter habit; longer creeping rhizomes; non-cauline leaf blades short and never reaching the inflorescence, flat and similar to the cauline leaves; ligule truncated or round up to 1 mm; panicle 3–5(8) cm, contracted and smaller, with few spikelets, up to 11; all branches shorter than the spikelets; caryopsis thickened, inrolled or plicate, 8–9 mm, shorter than palea. B.picoeuropeanus also differs in its preference for stony soils.
Description.
Perennial plant with long rhizomes 3–5(7) cm, loosely tufted. Flowering culms up to 40 cm. Culms channeled and glabrous, with glabrous nodes. Extravaginal innovation leaves with short blades, similar to the cauline leaves. Leaf sheaths of cauline leaves glabrous. Old basal leaf sheaths persistent, investing the culm base. Blade of cauline leaves 9–13 cm × 2–3 mm, tapering gradually towards the apex. Ligule membranous and glabrous, short, 0.5–1 mm, apex truncated or rounded, ± lacerated. Panicle 3–4(–8) × 2–3 cm, erect, lax, contracted, with 4–8(11) spikelets, branches slender. Scale of the lower node leaf-like, c. 4 mm, glabrous. Pedicels scabrid with fine antrorse teeth. All branches and pedicels shorter than spikelets. Spikelets 16–22(–25) × 3–5 mm, with two unequal glumes and 4–5(–7) fertile florets, imbricate when young, in maturity the florets slighted separated. Lower florets bisexual, 9–11(–12) mm, oblong, scaberulous toward the apex; upper floret male or sterile, 5–6 mm, lanceolate, glabrous, similar in color and texture to the lower florets. Lower glume 1–veined, narrow, 6–7 mm. Upper glume 3-veined, 7–9 mm. Lemma glabrous, lanceolate, section slightly keeled, 9–11(–12) mm (excluding the awns), 3–5-veined. Apex of the lemma slightly emarginate (sinus approximately 0.1 mm); margin rounded. Awn short, (2.5–) 3–4 (–5) mm, up to 1/3 the lemma length, fine and straight, inserted 1–1.5 mm below the apex. Rhachilla 2–3 mm, scabrid with very fine antrorse teeth. Callus short, glabrous and rounded. Palea linear-lanceolate of similar size or slightly shorter than the lemma, 8–11 × 1–2 mm, with aculeolate keels; wings nearly as wide as the palea body, with smooth border. Lodicules 2, lanceolate to oblong, glabrous, 0.5–1.5 mm long. Stamens 3, with anthers 3.5–4.5 mm long. Caryopsis elliptic, enrolled or plicate at maturity, 7–8 mm, shorter than palea (Fig. 1).
Bromuspicoeuropeanus. A Habit showing the developed rhizomes, the short basal leaves, and the contracted inflorescence B Spikelet with unequal glabrous glumes and five florets C Glumes D Palea in adaxial view, showing the two adaxial wings E Lemma in lateral view (drawn from the holotype) F Caryopsis in adaxial and abaxial view (drawn from LEB 121815). Drawings by Ms. Giulia Osti, 2018.
https://binary.pensoft.net/fig/296226Phenology.
Flowering July – August. Fruiting August – September.
Distribution and habitat.
Bromuspicoeuropeanus is endemic to the Iberian Peninsula and occurs in Spain, distributed through the Northern Mountains of the Cantabrian Range (Fig. 2). We collected it in several localities of Picos de Europa National Park, growing in dry rocky areas of limestone moving by gelifraction, and on stony areas at an altitude of 1600–2200 m.
Conservation status.
Bromuspicoeuropeanus occurs within the Picos de Europa National Park. Although the IUCN (2017) criterion B thresholds (EOO = 111.51 km2; AOO = 40.0 km2) suggest a different category [EN], the species has been evaluated DD (Data Deficient), because further study is needed to assess the risk.
Etymology.
The specific epithet is a reference to the Spanish National Park Picos de Europa, where it was collected.
Distribution map representing all the known locations of Bromuspicoeuropeanus.
https://binary.pensoft.net/fig/296227Discussion
Some thirty perennial species belonging to the genus Bromus occur in the Euro+Med area (Valdés and Scholz 2006; 2009). Five perennials live in the Iberian Peninsula (Smith 1980; Acedo and Llamas 1999) including the cultivated and naturalized Bromusinermis Leyss. extensively cultivated all over the world, the weeds B.catharticus Vahl, and B.sitchensis Trin., and the native perennial species, B.benekenii (Lange) Trim., B.ramosus Huds., and B.erectus. This last species is the only one known in the Iberian Peninsula belonging to the B.erectus complex until now.
The Bromuserectus complex is differentiated by its persistent basal sheaths remaining intact or decaying into parallel fibers, and the non-cauline basal leaves typically longer and narrower than the cauline leaves. Its inflorescence is lax, spread or contracted, with erect branches and pedicels, more or less developed, but some of the pedicels longer than the spikelet. The multiflorous spikelet is supported by two subequal or unequal glumes with 1–5 nerves (Smith 1981; Acedo and Llamas 1999; Cope and Gray 2009; Pignatti et al. 2017). Other perennial species have old basal sheaths forming a reticulum as B.moesiacus Vell. or B.riparius. The complex lacks auricles as opposed to other perennial species having long lanceolate auricles (e.g. B.biebersteinii) or diminished auricles (e.g. B.stenostachyus Boiss.).
The morphological traits of Bromuspicoeuropeanus suggest it must be classified within the Bromuserectus complex. Among the Iberian perennials, the specimens of B.picoeuropeanus are morphologically more similar to the widespread B.erectus. The presence of a developed rhizome 3–5(7) cm long (Fig. 1, 3) is a major difference with the remainder of the perennial Iberian taxa. This trait is relevant also in the differentiation of other perennial species such as the nemoral B.benekenii and B.ramosus (Cope and Gray 2009). There are other European species related to B.erectus which have rhizomes: B.moellendorffianus, B.pannonicus, B.riparius, or B.tomentellus. All of them, however, have very short rhizomes. The shoot leaf blades of B.picoeuropeanus are shorter (Fig. 1) than those of B.erectus, which has long and narrow leaves frequently reaching the inflorescence. Leaf hairs are very rare in B.picoeuropeanus, even more scarce than in B.erectus. In detailed descriptions of B.erectus, there is a large range of variability in other characters that are not useful for separating taxa: for instance, some floras (Pignatti et al. 2017) recognized Bromuslongiflorus Willd. ex Spreng. as having long spikelets with 11–13 florets, which is a variation of B.erectus. We have observed that the number of florets is a variable character in several species (Acedo and Llamas 1999; Acedo et al. 2009), and the floret number can be sometimes twice or more than its usual number.
A The preferred habitat of Bromuspicoeuropeanus in stony and unstable soils, c. 1900 m elevation, where it prefers steep slopes and stony grassland, and disappears when the slope decreases or the pasture becomes denser B Detail of the basal part of culms showing the long rhizomes and flat cauline leaves.
https://binary.pensoft.net/fig/296228
While Bromuserectus has a wide distribution in most of Europe (except on the Scandinavian peninsula and the adjacent Northeastern countries), B.picoeuropeanus is known only in the National Park of the Picos de Europa, a small territory of the Cantabrian range. B.picoeuropeanus differs also in its ecological behavior from all the native Iberian perennial species. B.benekenii and B.ramosus occur in nemoral habitats and B.erectus mainly in mesophyllous meadows. B.picoeuropeanus, by contrast, occurs in stony and rocky places.
Key to the perennial European species similar to Bromuspicoeuropeanus
1
Plants rhizomatous, laxly caespitose; shoot and cauline leaf-blades similar in width, leaves glabrous, scabrid or distinctly pilose
2
–
Plants without rhizomes or stolons, or inconspicuously rhizomatous, tufted, caespitose; cauline leaf blades wider than the lower, with scattered long (up to 1mm) and patent hairs
6
2
Leaves flat or slightly involute
3
–
Leaves conduplicate, or setaceous-conduplicate
4
3
Rhizome long; lemma 9–11(–12) mm, awn 3–5mm; caryopsis slightly thickened, inrolled at maturity, shorter than palea; leaves not auriculate; culms up to 40 cm
B.picoeuropeanus
–
Rhizome short, forming distinct clumps; lemma long 11–14(–20) mm, awn 5–8 mm; caryopsis almost flat, similar in length to the palea; lower leaves shortly auriculate; culms 50–90(–120) cm
B.riparius
4
Leaves and sheaths with long greyish hairs; spikelets 15–20(–25) mm
B.pannonicus
–
Indumentum of leaves different; spikelets 15–25(–35) mm, awn similar in length to the lemma or slightly shorter
5
5
Leaf sheaths and blades tomentose, covered by dense short and sparse long hairs; lemma 12–18 mm, awn 11–17mm
B.tomentellus
–
Leaf blades and sheaths glabrous, scarcely scabrid on the veins or distinct pilose, not tomentose; lemma 8–10(–15) mm, awn 7–9 mm
B.moellendorffianus
6
Leaf sheaths lanate-pubescent, with long and tangled hairs; the lower sheaths fibrous; panicle denser; lemma 8–9 mm
B.condensatus
–
Leaf sheaths not lanate-pubescent, the lower sheaths persistent, remaining intact when dead; panicle lax, lemma > 9 mm
7
7
Glumes subequal, florets strongly overlapped, for ¾ of their length by the floret below; panicle spread
B.erectus
–
Glumes markedly unequal; florets only slightly overlapped by the apex of the floret below
8
8
Lower sheaths densely pubescent; lemma 13–18 mm, longer than the upper glume; awn up to one half of lemma length
B.stenophyllus
–
Sheaths glabrous or with few scattered long (c. 1 mm) hairs; lemma short, c. 10 mm, similar in length to the upper glume; awn similar to lemma length
B.transsilvanicus
Other Bromuspicoeuropeanus specimens examined
Asturias: Vegarredonda, 43°14.44'N, 4°59.42'W, 1983, July 28, limestone, 1800 m alt., H.S.Nava s.n. (FCO 14203). Cantabria: Canal de Jenduda, 43°9.88'N, 4°48.88'W, 20 July 2008, 1810 m alt., C.Acedo & F.Llamas (v.v.); Canal de San Carlos, 43°12.70'N, 4°41.56'W, 6 August 1983, 1718 m alt., H.S.Nava s.n. (FCO 14201); Canto La Concha, 43°13.13'N, 4°40.81'W, 6 August 1983, 1660 m alt., H.S.Nava s.n. (FCO 14196); Majada de la Redondal, 43°12.52'N, 4°43.41'W, 3 August 1983, 1800 m alt., H.S.Nava s.n. (FCO 14200); Mancondiu, 43°12.96'N, 4°42.47'W, 6 August 1983, 1900 m alt., H.S.Nava s.n. (FCO 14199); Pozo de Ándara, 43°12.67'N, 4°43.80'W, 3 August 1983, 1730 m alt., H.S.Nava s.n. (FCO 14202); Samelar, 43°12.54'N, 4°41.90'W, 1 August 2007, 1700 m alt., C.Acedo & F.Llamas (v.v.); Vegas de Ándara: Fuente de la Escalera, 43°12.42'N, 4°42.20'W, 31 August 2011, 1869 m alt., C.Acedo, A.Alonso & F.Llamas CA247.1 (LEB121812); ibidem CA247.2 (LEB 121810); ibidem CA247.3 (LEB 121811); ibidem CA247.4, (LEB 121814); ibidem CA247.5 (LEB 121813); 50m East of the Fuente de la Escalera, 43°12.43'N, 4°41.99'W, 1 October 2017, 1886 m alt., V.Ezquerra & C. Frey s.n. (LEB 121815); Camino hacia Fuente de la Escalera, 43°12.46'N, 4°42.01'W, 1 October 2017, 1860, V.Ezquerra & C.Frey (v.v.), sink holes, 43°12.66'N, 4°42.25'W, 1 October 2017, 1789, V.Ezquerra & C.Frey (v.v.), road margin, 43°12.70'N, 4°42.24'W, 1 October 2017, 1787 m alt., V.Ezquerra & C.Frey (v.v.). León. Carbayal, 43°11.82'N, 4°57.11'W, 7 July 1983, 1800 m alt., H.S.Nava s.n.(FCO 14198); Las Colladinas, 43°10.84'N, 4°51.76'W, 22 July 1983, 2170 m alt., H.S.Nava s.n. (FCO 14197).
Acknowledgments
This research was partially supported by the Spanish Ministerio de Ciencia e Innovación, and Spanish Ministerio de Economía y Competitividad under Flora Iberica X (CGL2014-52787-C3-2-P/BOS), GrassModels (CGL2012-39953-C02-02), and Pooide (CGL2009-12955-C02-02) projects. The authors give many thanks to the curators of all the herbaria consulted, and would like to thank herbaria B, C, JBAG, LEB, FCO, FI, JACA, K, MA, MAF, MSNM, P, SALA, SANT, and VIT, and researchers who provided material from public or personal collections and provided loans and access to collections, although in some cases it was not included in this study. Thanks to Víctor Ezquerra and Carlos Frey for collecting the fruiting specimens in the locus classicus; Ms. Giulia Osti for drawing the holotype; Estrella Alfaro Ph.D. (LEB) for improving the distribution map, and Mrs. Amelia Llamas for proofreading the paper. Many thanks to the reviewers Martin Röser and Jeffery Saarela, and the communicating editor Maria Vorontsova for suggestions to improve the manuscript.
ReferencesAcedoCLlamasF (1999) Cramer, Berlin and Stuttgart, 293 pp.AcedoCLlamasF (2001) Variation of micromorphological characters of lemma and palea in the genus Bromus (Poaceae).38: 1–14. https://www.jstor.org/stable/23726828AcedoCMolinaALlamasF (2009) Variación morfológica de Bromuserectus Huds., en el eje pirenaico-cantábrico. Significado taxonómico. In: LlamasFAcedoC (Eds) Botánica Pirenaico-Cantábrica en el siglo XX., 123–144.AlonsoA (2015) PhD Thesis, University of León, Spain, 302 pp.AlonsoABullRDAcedoCGillespieLJ (2014) Design of plant-specific PCR primers for the ETS region with enhanced specificity for tribe Bromeae and their application to other grasses (Poaceae).92(10): 693–699. https://doi.org/10.1139/cjb-2014-0062BachmanSMoatJHillAde la TorreJScottB (2011) Supporting Red List threat assessments with GeoCAT: Geospatial Conservation Assessment Tool.150: 117–126. https://doi.org/10.3897/zookeys.150.2109BačičTJoganN (2001) Multivariate morphometric study of the Bromuserectus group (Poaceae-Bromeae) in Slovenia.41(2): 295–311.CopeTGrayA (2009) Grasses of the British Isles. B.S.B.I. Handbook No. 13. Botanical Society of the British Isles, London, 83–85, 434–479.FedorovA (1999) Flora of Russia, the European part and bordering regions. Vol. 1. AA Balkema, Roterdam, Brookfield, 237–254.IUCN (2017) Guidelines for using the IUCN red list categories and criteria. Version 13. Prepared by the standards and petitions subcommittee. Downloadable from http://www.iucnredlist.org/documents/RedListGuidelines.pdfLlamasFAcedoC (2019) Typification of eight current and seven related names, and a new section in the genus Bromus (Bromeae, Pooideae, Poaceae). PhytoKeys 119.MaireRGuinochetMFaurelL (1955) Lechevalier, Paris, 395 pp.NaderiRRahiminejadMR (2015) A taxonomic revision of the genus Bromus (Poaceae) and a new key to the tribe Bromeae in Iran.52(3–4): 233–248. https://doi.org/10.5735/085.052.0316OganesianME (2004) Bromopsisgabrielianae (Poaceae) a new species from Southern Armenia.15: 11–13.OjaTZimmermannK (2010) Genetic variation of Bromushordeaceuss. lato (Poaceae) over its core distribution range.47(3): 161–174. https://doi.org/10.5735/085.047.0301PignattiSGuarinoRLa RosaM (2017) Flora d’Italia. Vol. 1. Edagricole. Bologna, 679–694.SaarelaJM (2008) Taxonomy of Bromus (Poaceae: Pooideae: Bromeae) sections Bromopsis, Bromus, and Genea in British Columbia, Canada.2(1): 323–372.SaarelaJMPetersonPMKeaneRMCayouetteJGrahamSW (2007) Molecular phylogenetics of Bromus (Poaceae: Pooideae) based on chloroplast and nuclear DNA sequence data.23(1): 450–467. https://doi.org/10.5642/aliso.20072301.35SaarelaJMPetersonPMValdés-ReynaJ (2014) A taxonomic revision of Bromus (Poaceae: Pooideae: Bromeae) in México and Central America.185(1): 1–147. https://doi.org/10.11646/phytotaxa.185.1.1SmithPM (1972) Serology and species relationships in annual bromes (BromusL.sect.Bromus).36(1969): 1–30.SmithPM (1980) Bromus L. In: TutinTGHeywoodVHBurguesNAMooreDMWalterSMWebbDA (Eds) Flora Europaea Vol., 182–189.SmithPM (1981) Ecotypes and subspecies in annual brome-grasses (Bromus, Gramineae). Botanische Jahrbücher für Systematik, Pflanzengeschichte und Pflanzengeographie 102(1/4): 497–509.SmithPMSalesF (1993) BromusL.sect.Bromus: Taxonomy and relationship of some species with small spikelets.50(2): 149–171. https://doi.org/10.1017/S0960428600002535StebbinsGL (1981) Chromosomes and evolution in the genus Bromus (Graminae).102(1–4): 359–379.ThiersB (2018) [continuously updated] Index Herbariorum: A global directory of public herbaria and associated staff. New York Botanical Garden’s Virtual Herbarium. http://sweetgum.nybg.org/ih/ [Accessed 9 February 2017]TurlandNJWiersemaJHBarrieFRGreuterWHawksworthDLHerendeenPSKnappSKusberWHLiDZMarholdKMayTWMcNeillJMonroAMPradoJPriceMJSmithGF (Eds) (2018) International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017. Regnum Vegetabile 159. Koeltz Botanical Books, Glashütten. https://doi.org/10.12705/Code.2018TzvelevNN (1976) Grasses of the Soviet Union. Vol.1, Leningrad, Nanka. [English translation 1983, New Delhi, Oxonion Press, 298–343]ValdésBScholzH (2006) The Euro+Med treatment of Gramineae – A generic synopsis and some new names.36(2): 657–669. https://doi.org/10.3372/wi.36.36202ValdésBScholzH (2009) with contributions from Raab-Straube E von, Parolly G, Poaceae (pro parte majore). Euro+Med Plantbase – the information resource for Euro-Mediterranean plant diversity. http://www.emplantbase.org/home.html [Accesed July 2018]