Bromus secalinus
(rye brome)

Pictures

Picture	Title	Caption	Copyright
Title Seedheads Caption Bromus secalinus (rye brome); habit, showing seedheads. Copyright ©Kurt Stüber/via wikipedia - CC BY-SA 3.0	Seedheads	Bromus secalinus (rye brome); habit, showing seedheads.	©Kurt Stüber/via wikipedia - CC BY-SA 3.0
Title Seeds Caption Bromus secalinus (rye brome); seeds. Note mm scale. Copyright ©Bruce Ackley/The Ohio State University/Bugwood.org - CC BY 3.0 US	Seeds	Bromus secalinus (rye brome); seeds. Note mm scale.	©Bruce Ackley/The Ohio State University/Bugwood.org - CC BY 3.0 US

Identity

Preferred Scientific Name

• Bromus secalinus L.

Preferred Common Name

• rye brome

Other Scientific Names

• Avena secalina Salisb.
• Bromus mollis var. secalinus (L.) Huds.
• Bromus mutabilis var. secalinus (L.) F.W.Schultz
• Bromus secalinus var. vulgaris W.D.J.Koch
• Bromus segetalis var. secalinus (L.) Döll
• Forasaccus secalinus (L.) Bubani
• Serrafalcus secalinus (L.) Bab.

International Common Names

• English: bromegrass; cheat; cheat grass; cheatgrass; chess; chess brome; chess bromegrass; cock grass; rye bromegrass; ryebrome; smooth rye brome grass; wheat-thief
• Spanish: bromo del centeno; bromo secalino; pasto valcheta
• French: brome des champs; brome des seigles; brome faux-seigle; seglin; seigle bâtard
• Russian: koster rzhanoi
• Chinese: hei mai zhuang que mai
• Portuguese: bromo-centeio; capim-cevadinha

Local Common Names

• Czech Republic: sverep stoklasa
• Denmark: rughejre
• Finland: ruiskattara
• Germany: Roggen-Trespe
• Italy: bromo segalino; forasacco delle messi; forasacco segalino; segala lanaiuola
• Japan: karasunochahiki
• Netherlands: dreps
• Poland: stoklosa zytnia
• Sweden: råglosta
• Turkey: cavdar bromu

EPPO code

• BROSE (Bromus secalinus)

Summary of Invasiveness

Bromus secalinus is a serious grassy weed infesting winter rye (Secale cereale), winter wheat (Triticum aestivum) and other cereal crops. As its life cycle fully coincides with that of the cereal crop it infests, at harvesting it can become a major contaminant of cereal seed for sowing. Originating in Eurasia, it has been spread most likely through contaminated grain shipments to North America, Australia and elsewhere. It has proved invasive of disturbed land, dry prairies, limestone glades, meadows, vacant lots, abandoned fields, crop land, field margins, roadsides, railroad tracks and waste places, displacing native vegetation.

Taxonomic Tree

• Domain: Eukaryota
•     Kingdom: Plantae
•         Phylum: Spermatophyta
•             Subphylum: Angiospermae
•                 Class: Monocotyledonae
•                     Order: Cyperales
•                         Family: Poaceae
•                             Genus: Bromus
•                                 Species: Bromus secalinus

Notes on Taxonomy and Nomenclature

Bromus L. is a taxonomically complex genus that includes 169 annual and perennial grass species with wide geographical distribution in temperate regions (Saarela, 2008; The Plant List, 2013).

Bromus secalinus L. is an accepted name. There are 8 homotypic synonyms and 50 heterotypic synonyms (WCSP, 2016). There are no infraspecific taxa (The Plant List, 2013).

The generic name Bromus derives from the Greek word bromo meaning food which was in Classical times the Greek name for oats. The specific epithet secalinus is a reference to being found in rye (Secale cereale) crops (Clifford and Bostock, 2007); several of this species’ common names allude to its similarity to or association with rye. B. secalinus is also often referred to as 'chess' or 'cheat,' although these common names may also refer to other annual Bromus species from Eurasia (Hilty, 2015).

Description

The description of B. secalinus given by Clayton et al. (2016) states:

Annual; culms solitary, or caespitose. Culms erect; 20-120 cm long; 5-7-noded. Leaf-sheaths glabrous on surface. Ligule an eciliate membrane; 1-2 mm long; erose. Leaf blades 10-25 cm long; 4-10 mm wide. Leaf-blade surface scaberulous; pubescent.

Inflorescence a panicle. Panicle open, or contracted; ovate; equilateral, or nodding; 5-20 cm long. Primary panicle branches 2-8 cm long; bearing 1-4 fertile spikelets on each lower branch. Panicle branches scabrous; glabrous or pubescent. Spikelets solitary. Fertile spikelets pedicelled. Pedicels 10-30 mm long. Spikelets comprising 4-11 fertile florets; with diminished florets at the apex. Spikelets oblong, or ovate; laterally compressed; compressed slightly; 12-25 mm long; 4-7 mm wide; breaking up at maturity; disarticulating below each fertile floret. Glumes persistent; dissimilar; shorter than spikelet; parallel to lemmas. Lower glume oblong or ovate; 4.6-6.5 mm long; 0.7-0.8 length of upper glume; coriaceous; without keels; 3-5-veined. Lower glume apex acute. Upper glume elliptic or ovate; 5-8.5 mm long; 0.7-0.9 length of adjacent fertile lemma; coriaceous; without keels; 5-7-veined. Upper glume apex obtuse.

In florets, fertile lemma elliptic; 6-10 mm long; 4-11 mm wide; coriaceous; much thinner on margins; without keel; 7-9 -veined. Lemma margins involute. Lemma apex muticous or awned; 1-awned. Principal lemma awn subapical; 0-8 mm long overall; limb scabrous. Palea 1 length of lemma. Palea keels ciliolate. Apical sterile florets resembling fertile though underdeveloped.

In the flower, lodicules 2; membranous. Anthers 3; 1-2 mm long. Ovary with a fleshy appendage above style insertion; pubescent on apex. Fruit a caryopsis with adherent pericarp; ellipsoid; hairy at apex; apex fleshy. Hilum linear; 1 length of caryopsis.

Plant Type

Distribution

The extent of the native distribution of B. secalinus in Europe is confused, no doubt by the fact that its seed would have been widely distributed geographically in prehistoric times by early farmers and traders as a contaminant of cereal grain. As a consequence, some authorities cite it as a mainly European species growing all over western Europe (except the far south), as well as the Caucasus, Mediterranean region and Asia Minor, extending its eastward limit into parts of European Russia, especially the north-west of Central Russia but not as far north as the Arctic (Afonin et al., 2016). USDA-ARS (2016), on the other hand, gives its native range as eastern, central, southeastern and southwestern Europe, Algeria, Republic of Georgia and Turkey, while the Royal Botanic Gardens Kew (2016) limits the native distribution to southwestern, east-central and southern Europe, the Transcaucasus, the Middle East, Siberia and northern China, with northern Europe, Algeria and most of European Russia defined as the introduced Eurasian range.

According to Afonin et al. (2016), beyond Central Russia B. secalinus is adventive, from southern Siberia to Russia’s Far East. The Flora of China (Flora of China Editorial Committee, 2016) is unclear about its native status but includes it as found in Xinjiang, Gansu, Tibet, Taiwan and Japan.

B. secalinus is an introduced species across much of North America. Present in all contiguous states of the USA except North Dakota, as well as Alaska and Hawaii, and most provinces in western and eastern Canada (USDA-NRCS, 2016), B. secalinus is listed as invasive in Arkansas, Illinois, Tennessee, Georgia and Florida (Invasive.org, 2016). In Hawaii it has been recorded naturalized at Kipukapuaulu in the Hawaii Volcanoes National Park on the island of Hawaii (Wagner et al., 2005). In Canada, the species has been reported from the Yukon, British Columbia, Alberta, Ontario, Quebec, New Brunswick, Nova Scotia, Newfoundland and Prince Edward Island (Canadian Food Inspection Agency, 2015).

Having been accidentally introduced into Australia, B. secalinus is now naturalized in New South Wales, Victoria and Tasmania (Atlas of Living Australia, 2016). Populations of the species have also been observed in Mexico (eMonocot, 2016), Argentina and Chile (Royal Botanic Gardens Kew, 2016).

Distribution Table

The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.

History of Introduction and Spread

As a previously very common weed of wheat and especially rye crops, it would have reached maturity at the same time as the crop and thus benefited from harvesting at the appropriate stage in its life cycle to allow its viable seed to contaminate cereal seed lots and thus be dispersed as a contaminant with the cereal seed locally, nationally and even internationally, this probably being the main method of its introduction by early colonists from Europe to North America, Australia and elsewhere.

In the eastern USA, Mack (2003) notes that B. secalinus, along with a number of other agricultural weeds, were widespread but probably not invasive until 1860.

Risk of Introduction

As a cereal seed contaminant difficult to identify and eliminate, the risk of introduction to other regions is high.

Habitat

As an aggressive weed, rye brome invades open, disturbed areas below 1500 m elevation, dry prairies, limestone glades, disturbed grassy meadows, vacant lots, abandoned fields, crop land, field margins, roadsides, railroad tracks and waste places. It is a weed of winter wheat, rye and lucerne fields. This grass species is able to adapt to many soil types, from mesic to dry soils in full sun. It prefers heavy, clay, over-wet and cold soils (Baldwin et al., 2012; Darbyshire, 2003; Saarela and Peterson, 2016; Afonin et al., 2016; Invasive.org, 2016; Tennessee Exotic Pest Plant Council, 2016).

Habitat List

Hosts/Species Affected

Rye brome is a noxious weed of cereal crops, especially wheat and rye but also barley, and of grass crops.

Host Plants and Other Plants Affected

Growth Stages

Biology and Ecology

Genetics

B. secalinus is an allotetraploid with a chromosome number of 2n = 28 (Spalton, 2002; Saarela and Peterson, 2016)

Reproductive Biology

B. secalinus is an annual cross-pollinated grass reproducing exclusively by seed (Tennessee Exotic Pest Plant Council, 2016). According to Afonin et al. (2016), one plant can produce up to 5000-6000 caryopsides, although Nádasyné Ihárosi and Nagy (2010) give a figure of 800-1600 seeds per plant.

Physiology and Phenology

Anthesis in B. secalinus takes place from around May to July (Saarela and Peterson, 2016), with fruits produced in July-August. Where it is a weed of cereals, its life cycle coincides with that of the crop (Afonin et al., 2016). In Oklahoma in the south-central USA, rye brome germinates in the autumn (from late August to mid-November), increases its reproductive tillers as it grows vegetatively through the autumn and winter months, initiates its reproductive growth in mid-March, flowers and sets seed in May, and finally matures in early June (Armstrong and Peeper, undated).

Longevity

B. secalinus is an annual plant but has been reported to form a short-term persistent soil seed bank. Seeds are able to survive in soil for over 1 year but less than 5 years (Thompson et al., 1997).

Associations

Predominantly found as a very common and dominant weed of cereal crops (wheat, rye, barley), B. secalinus is also found in association with other grass species. For example, in Taiwan, it has been observed growing together with Dactylis glomerata, Festuca arundinacea, Miscanthus sinensis, Poa annua and Vulpia myuros (Jung et al., 2006).

Environmental Requirements

B. secalinus prefers full sun and mesic to dry conditions. Seeds are able germinate in both natural light and in darkness. Germination ability significantly depends on depth of burial in the soil, with the best germination achieved when diaspores are on the soil surface (Kapeluszny and Haliniarz, 2007).

In the USA, rye brome is common in the eastern portion of the hard red winter wheat and more humid soft red winter wheat regions where the soils are acid sandy or loamy (Peeper, 1984), while in northwestern Russia it has a preference for heavy, clay, over-wet and cold soils, being rare on loam and sandy loam soils (Afonin et al., 2016). However, the grass will adapt to practically any kind of soil, and in areas of exposed open ground it can reseed itself aggressively (Hilty, 2015). In northeastern Poland, where B. secalinus appears to be becoming more frequent in cereal crops, it was observed on all soil types and in all soil-agricultural complexes, but was most frequent in winter cereals on compacted soils with pH values from 5 to 7.5 (Rzymowska et al., 2010).

Climate

Latitude/Altitude Ranges

Soil Tolerances

Soil drainage

• free
• impeded
• seasonally waterlogged

Soil reaction

• acid
• neutral

Soil texture

• heavy
• light
• medium

Natural enemies

Notes on Natural Enemies

B. secalinus is a host of wheat High plains virus which has been reported in the USA since 1993 and can cause severe symptoms (stunting, chlorosis and mortality) in both maize and wheat (EPPO, 2016).

The following insect species have been recorded feeding on B. secalinus and other Bromus species:

• Stink bugs (Pentatomidae) Aelia americana, Cosmopepla lintneriana, Hymenarcys aequalis, Hymenarcys nervosa and Mormidea lugens;
• Leaf beetles (Chrysomelidae) Chalepus walshii and Oulema melanopus;
• Grasshoppers (Acrididae) Ageneotettix deorum, Arphia simplex, Eritettix simplex, Hippiscus ocelote, Melanoplus bivittatus, Melanoplus confusus, Melanoplus femurrubrum, Melanoplus keeleri luridus, Melanoplus packardii, Melanoplus sanguinipes, Orphulella speciosa, Pardalophora haldemanii, Phoetaliotes nebrascensis and Syrbula admirabilis.

Additionally, small rodents such as Microtus ochrogaster feed on seeds and foliage of B. secalinus, while immature foliage is eaten by white-tailed deer (Odocoileus virginianus), cattle and other mammalian herbivores. The seeds are also eaten by upland gamebirds and sparrows (Hilty, 2015).

Means of Movement and Dispersal

Natural Dispersal

Seeds of B. secalinus can be dispersed short distances by wind.

Vector Transmission (Biotic)

The seeds of B. secalinus are spread by animals and humans because the mature lemmas can cling to fur and clothing (Hilty, 2015). Seeds can also be spread in cattle faeces as they remain viable even after passing through the animals’ digestive tracts (Armstrong and Peeper, undated).

Accidental Introduction

Rye brome has non-shattering seeds that, due to the weed’s similar life-cycle, easily contaminate grain from winter cereal crops. It is, thus, often reintroduced into fields through the use of contaminated cereal seed for sowing (Afonin et. al., 2016). In Canada it has been found in domestic rye (Secale cereale), smooth bromegrass (Bromus inermis), orchardgrass (Dactylis glomerata) and mixed forage seed. It is also found as a contaminant in wheat (Triticum aestivum) grain, more often from eastern Canada than from the west (Canadian Food Inspection Agency, 2015).

Dried B. secalinus plants are used in floral arrangements (Oakes, 1990). In Finland’s Åland Islands, B. secalinus was found in an area used for the disposal of florists’ waste (Carlsson et al., 2014).

Pathway Causes

Pathway Vectors

Plant Trade

Impact Summary

Economic Impact

B. secalinus occurs as a seed and grain contaminant. In Canada it has been found in domestic rye (Secale cereale), smooth bromegrass (Bromus inermis), orchardgrass (Dactylis glomerata) and mixed forage seed. It is also found as a contaminant in wheat (Triticum aestivum) grain, more often from eastern Canada than from the west (Canadian Food Inspection Agency, 2015).

Rye brome has been a very common and dominant weed of cereal crops in the past, even since prehistoric times; for example, an archaeological find of a rye grain lot from the 17th century in Europe consisted of 12% B. secalinus seed (Witmack, 1888). Recognizing that the weed caused reductions in crop grain yields and compromised the quality of seed for sowing, seed cleaning was adopted early on. One method, existing since the Neolithic (Knörzer, 1971) right up to the present, is based on the difference in terminal velocity between weed and cereal diaspores (Tackenberg, 2001). However, the long-standing use of this method resulted in the inadvertent selection of weeds with diaspore characteristics similar to those of the crop (large, heavy diaspores), which could not then be separated by traditional methods of seed cleaning (Barrett, 1983).

However, with the advent of improved methods of removing contaminants from cereal grain, B. secalinus is now generally in decline as an agricultural weed and is fairly uncommon or rare (Hubbard, 1954). Despite its decline in some regions, B. secalinus is still considered widespread in North America (Barkworth et al., 2007) and a major weed problem in the hard red winter wheat growing areas of the southern Great Plains (Stone et al., 2001). Field studies in Oklahoma have shown yield losses of 28-48% when winter wheat was competing with a 25 plants/m² average density of B. secalinus (Ontario Ministry of Agriculture, Food and Rural Affairs, 2016).

Seed of B. secalinus is restricted in several US states and is prohibited in India, Taiwan and possibly other countries. Therefore any amount of B. secalinus seed found in grain samples could have negative trade implications (Ontario Ministry of Agriculture, Food and Rural Affairs, 2016).

As a secondary host of High plains virus (EPPO, 2016), the presence of infected B. secalinus can have negative economic effects on cereal crop yields. The presence of the weed, whether infected with the virus or not, has cost implications for its control.

Environmental Impact

Impact on Habitats

B. secalinus is an aggressive weed that invades dry prairies, limestone glades and disturbed grassy meadows, displacing native plants (Invasive.org, 2016).

Threatened Species

Risk and Impact Factors

• Invasive in its native range
• Proved invasive outside its native range
• Has a broad native range
• Abundant in its native range
• Highly adaptable to different environments
• Tolerates, or benefits from, cultivation, browsing pressure, mutilation, fire etc
• Pioneering in disturbed areas
• Tolerant of shade
• Benefits from human association (i.e. it is a human commensal)
• Fast growing
• Has high reproductive potential
• Has propagules that can remain viable for more than one year

• Ecosystem change/ habitat alteration
• Negatively impacts agriculture
• Reduced native biodiversity
• Threat to/ loss of native species
• Negatively impacts trade/international relations

• Competition - monopolizing resources
• Pest and disease transmission

• Highly likely to be transported internationally accidentally
• Difficult to identify/detect as a commodity contaminant
• Difficult/costly to control

Uses

Economic Value

B. secalinus has in the past been occasionally utilized for hay in Washington and Oregon, USA (Hitchcock, 1935).

Social Benefit

B. secalinus has been tolerated as a weed in cereal crops up to the early twentieth century and in some countries, such as Poland, where it was used as famine food to make gruel or bread (Luczaj and Szymanski, 2007; Marekovic et al., 2015). Rye brome is also sometimes grown as an ornamental (Oakes, 1990): the dry purplish seed heads are considered attractive on the plant and in dried floral arrangements, and the species is considered a useful ground cover along highways.

Environmental Services

Seed of B. secalinus is a food source for small rodents and birds, while the foliage is eaten by deer and other herbivores (Hilty, 2015).

Uses List

Animal feed, fodder, forage

• Fodder/animal feed
• Forage

Environmental

• Wildlife habitat

Human food and beverage

• Emergency (famine) food

Ornamental

• Cut flower

Similarities to Other Species/Conditions

B. secalinus is readily identified when it is in fruit. However before fruiting it is more difficult to distinguish this species from B. racemosus and B. commutatus (Bomble and Scholz, 1999; Spalton, 2002).

According to Parnell (1845), B. secalinus can be distinguished from other Bromus species in the apex of the large glume being situated half-way between the base of the glume and the summit of the second floret on the same side; and in the outer palea being rounded on the upper margin, with the breadth considerably greater than half its length.

In the UK, B. secalinus is often confused with B. hordeaceus and particularly B. commutatus. Diagnostic features of the three species are outlined by Moss (2015). In B. secalinus lower leaf sheaths can be hairless or hairy, but are always hairy in the other two species. Panicles are usually compact in B. hordeaceus but loose in the other two species. Spikelets are hairy or hairless in B. secalinus, but usually softly hairy in B. hordeaceus and hairless in B. commutatus. Mature spikelets of B. secalinus when viewed from the side have visible gaps, but usually no gaps are visible in the other two species. The most reliable diagnostic feature is the cross section of mature seeds, which is a deep V or U shape in B. secalinus but saucer-shaped in B. hordeaceus and B. commutatus.

Tennessee Exotic Pest Plant Council (2016) lists the following species as landscape alternatives that may be confused with B. secalinus: Andropogon ternarius, Calamagrostis canadensis and Chasmanthium latifolium.

Prevention and Control

Prevention and Control

Control techniques for B. secalinus are limited, with the main focus being on its control in cereal crops, especially wheat. There is little focus on its removal from natural areas. Effective control measures for the weed in wheat are described in detail by Armstrong and Peeper (undated).

Prevention

The control of rye brome plants growing along borders, fence rows and roadsides before they produce seed can prevent spread into cereal fields. All farm equipment to be used in wheat fields should be cleaned thoroughly to prevent transfer of seed and seedlings (Armstrong and Peeper, undated). Cereal seed needs to be properly cleaned to eliminate B. secalinus and other weed seeds. Hauhouot et al. (1998) showed that rye brome seeds could be devitalized after secondary cleaning using mechanical devices such as hammer and roller mills mounted on the combine harvester. These dehulled the seeds and fractured the seed embryos, thus significantly reducing weed seed germination.

Where B. secalinus has invaded natural areas, cutting and mowing of populations before flowering will reduce the seed bank (Tennessee Exotic Pest Plant Council, 2016).

Cultural Control and Sanitary Measures

Cultural practices that encourage a vigorous winter wheat crop will help it to gain a competitive advantage over rye brome. Tillage can control weed seedlings if done before the wheat crop is sown or established. The wheat seed sown should be brome-free. Increased sowing rates and narrower row spacing help to increase the competitive ability of the wheat. Delaying wheat sowing till after the brome germinates allows seedlings to be destroyed with tillage or herbicides. Deep ploughing can effectively bury brome seed (Armstrong and Peeper, undated).

Crop rotation accompanied by herbicide application has shown increases in total net production of wheat. Stone et al. (2006) found that rotating out of winter wheat for one growing season increased grain yield in the succeeding wheat crop by up to 42%, while dockage due to B. secalinus was reduced by up to 87%.

Although wheat harvesting equipment can be adjusted to discharge a larger proportion of the rye brome seeds back into the field rather than into the grain bin, the concentration of weed seeds left behind can increase the difficulty of controlling infestations (Stone et al., 2001).

Movement Control

B. secalinus is recognized as a noxious weed seed under the US Federal Seed Act. This designation does not allow seed lots with over 300 rye brome seeds per pound of certified seed to be imported into the following states: Alabama, Arkansas, Delaware, Florida, Georgia, Kansas, Louisiana, Mississippi, New Jersey, Oklahoma, South Carolina, Tennessee and Texas. India and Taiwan totally prohibit the importation of B. secalinus (Ontario Ministry of Agriculture, Food and Rural Affairs, 2016).

Chemical Control

As a result of recent advancements in herbicide chemistry, effective herbicides are available for rye brome control in wheat. Several herbicides selectively kill rye brome when applied post-emergence, with minimal if any injury to the wheat. These include propoxycarbazone-sodium, propoxycarbazone-sodium + mesosulfuron-methyl, pyroxsulam and chlorsulfuron + metsulfuron-methyl. Sulfosulfuron can be applied both pre- and post-emergence. Imidazolinone herbicides can be used for rye brome control only with imidazolinone-resistant wheat (Armstrong and Peeper, undated). Using herbicides with different modes of action is important in control regimes to prevent the development of herbicide resistance in weed species. Resistance of B. secalinus biotypes in wheat crops to several Group 2 herbicides (imazamox, propoxycarbazone-sodium, pyroxsulam and sulfosulfuron) has already been reported in Kansas and Oklahoma (Heap, 2016).

As virtually all of these herbicides can control other grassy weed species, their use would be inappropriate in conditions where B. secalinus is growing with mixed native grasses.

Synowiec and Kalemba (2015) reported that essential oil distilled from Heracleum sosnowskyi seeds has potential to be used as a natural herbicide against weeds in maize; even a relatively small dose of 0.2 g/litre caused a significant reduction in germination and seedling growth of B. secalinus.

Gaps in Knowledge/Research Needs

Most of the literature regarding B. secalinus concentrates on the species as a weed of cereal crops. There appears to be little research on it as an invasive impacting on natural plant communities and ecosystems, such as the North American prairies, or on its control in these situations.

References

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Armstrong J, Peeper TF, undated. Cheat control in Oklahoma winter wheat. Oklahoma Cooperative Extension Service Fact Sheet, PSS-2774, 8 pp. http://www.okrangelandswest.okstate.edu/files/invasive%20species%20pdfs/PSS-2774.pdf

Atlas of Living Australia, 2016. Bromus secalinus L., rye brome. Canberra, ACT, Australia: National Collaborative Research Infrastructure Strategy (NCRIS). http://bie.ala.org.au/species/Bromus+secalinus

AVH, 2015. Australia's Virtual Herbarium. Canberra, ACT, Australia: Council of Heads of Australasian Herbaria. http://avh.chah.org.au/

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Barkworth ME, Capels KM, Long S, Anderton LK, Piep MB, 2007. Grass manual on the Web. Flora of North America, Vol. 24. Logan, Utah, USA: Utah State University. http://herbarium.usu.edu/webmanual/

Barrett SCH, 1983. Crop mimicry in weeds. Economic Botany, 37(3):255-282.

Bomble W, Scholz H, 1999. A new subspecies of Bromus secalinus (Gramineae) - a secondary weed. (Eine neue Unterart des Bromus secalinus (Gramineae) - ein sekundäres Unkraut.) Feddes Repertorium, 110(5/6):425-438.

Canadian Food Inspection Agency, 2015. Review of proposed listing of four Bromus species as Class 3 secondary noxious on the Weed Seeds Order of the Seeds Regulations. Ottawa, Ontario, Canada: Canadian Food Inspection Agency, 38 pp. [Information request. PRA Request: 2015-08.] http://cdnseed.org/wp-content/uploads/2015/05/CFIA-Risk-Assessment-Bromus-Species.pdf

Carlsson R, Haeggstrom CA, Sundberg K, 2014. Ruderal vascular plants on a waste ground in the Island of Dano, Aland Islands, SW Finland. Memoranda Societatis pro Fauna et Flora Fennica, 90:55-66.

Clayton WD, Vorontsova MS, Harman KT, Williamson H, 2016. GrassBase - The Online World Grass Flora. Kew, UK: Royal Botanic Gardens. http://www.org/data/grasses-db.html

Clifford HT, Bostok PD, 2007. Etymological dictionary of grasses. Heidelberg, Germany: Springer-Verlag GmbH, xii + 319 pp.

Darbyshire SJ, 2003. Inventory of Canadian Agricultural Weeds. Ottawa, Canada: Agriculture and Agri-Food Canada, 396 pp.

eMonocot, 2016. eMonocot - an online resource for monocot plants. http://e-monocot.org/

EPPO, 2016. PQR - EPPO Plant Quarantine Data Retrieval System, version 5.3.5. Paris, France: OEPP/EPPO. http://www.eppo.int/DATABASES/pqr/pqr.htm

Flora of China Editorial Committee, 2016. Flora of China. St. Louis, Missouri and Cambridge, Massachusetts, USA: Missouri Botanical Garden and Harvard University Herbaria. http://www.efloras.org/flora_page.aspx?flora_id=2

Hauhouot M, Solie JB, Brusewitz GH, Peeper TF, 1998. Roller and hammer milling cheat (Bromus secalinus L.) to reduce germination as an alternative method for weed control. Transactions of the ASAE, 41(4):973-980.

Heap I, 2016. International survey of herbicide resistant weeds. Lawrence, KS, USA: Weed Science Society of America. www.weedscience.com

Hilty J, 2015. Illinois wildflowers. Illinois, USA. http://www.illinoiswildflowers.info/index.htm

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Hubbard CE, 1954. Grasses. A guide to their structure, identification, uses, and distribution in the British Isles. Harmondsworth, UK: Penguin Books Ltd., 402 pp.

Invasive.org, 2016. Rye brome, Bromus secalinus L. Athens, GA, USA: Center for Invasive Species and Ecosystem Health, University of Georgia. http://www.invasive.org/browse/subinfo.cfm?sub=5212

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Contributors

11/04/2016   Original text by:

Lukasz Tymo, CABI, UK

Distribution Maps