''Bromus diandrus'' is a species of

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

known by the common names great brome and "

ripgut brome Ripgut brome or ripgut grass refers to some species of brome grasses (''Bromus''): * '' Bromus diandrus'' (great brome) * '' Bromus rigidus'' (stiff brome) The name refers to the fact that even for brome grasses, these species are heavily sclerot ...

Description

This is a brome grass which is native to the

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but has been introduced to much of the rest of the world. It does best in areas with a

Mediterranean climate A Mediterranean climate (also called a dry summer temperate climate ''Cs'') is a temperate climate sub-type, generally characterized by warm, dry summers and mild, fairly wet winters; these weather conditions are typically experienced in the ...

, such as California and parts of southern Australia, but it is quite tolerant of many climates. Ripgut brome is a winter annual that grows throughout winter and spring and matures in the summer. The adult plant is one to three feet in height with hairy, rough leaves about a centimeter wide. The membranous

ligule A ligule (from "strap", variant of ''lingula'', from ''lingua'' "tongue") is a thin outgrowth at the junction of leaf and leafstalk of many grasses (Poaceae) and sedges. A ligule is also a strap-shaped extension of the corolla, such as that of a ...

is prominent, white with spiky hairs. The wide

panicle A panicle is a much-branched inflorescence. (softcover ). Some authors distinguish it from a compound spike inflorescence, by requiring that the flowers (and fruit) be pedicellate (having a single stem per flower). The branches of a panicle are of ...

nods like that of an

oat The oat (''Avena sativa''), sometimes called the common oat, is a species of cereal grain grown for its seed, which is known by the same name (usually in the plural, unlike other cereals and pseudocereals). While oats are suitable for human con ...

plant, and it bears a large, splayed spikelet with a very long

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which can exceed five centimeters in length. The seeds easily break out of the spikelet. They are very sharp and very rough due to tiny barb-like hairs that face backward, allowing the seed to catch and lodge-like a

fish hook A fish hook or fishhook, formerly also called angle (from Old English ''angol'' and Proto-Germanic ''*angulaz''), is a hook used to catch fish either by piercing and embedding onto the inside of the fish mouth (angling) or, more rarely, by impa ...

. This characteristic makes the seeds a danger to animals, which can easily get a seed lodged in a paw or eye. Motion can cause the seed to work itself deeper into the flesh. This is one of the grass species known to pet owners as " foxtails", a backyard hazard for outdoor cats and dogs.

Invasive species

Ripgut brome can substantially reduce yields when it invades wheat fields. It has naturalized in some areas and is considered a troublesome

noxious weed A noxious weed, harmful weed or injurious weed is a weed that has been designated by an agricultural or other governing authority as a plant that is injurious to agricultural or horticultural crops, natural habitats or ecosystems, or humans or liv ...

in others. ''Bromus diandrous'' is an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

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habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s. This bromegrass is a troublesome weed in cereal crops and natural pasture lands. The life cycle of ''B. diandrous'' helps it to grow in wheat fields in which it can grow for most of the season without being noticed. Once the grass starts flowering, the open

seed head shows the infestation.
Dastgheib F. & Poole N. 2010. Seed biology of bromegrass weeds (Bromus diandrous and B. hordeaceus) and effects of land management. New Zealand Plant Protection 63: 78-83 The damage to wheat crop is through both strong competition, lowering yield, and seed contamination, lowering quality. Methven1

Ripgut brome is also troublesome in rangeland if it establishes in high numbers. The grass is of low nutritional value to livestock. Brome seeds can also mix with sheep wool and lower its value. Moreover, sharp awns of ripe seeds can penetrate sheep's skin into the flesh causing pain and lowering carcass value. If ingested, the strong awns can cause injury to sheep's mouth and even intestine,Edgar E. & Connor H.E. 2000. Flora of New Zealand, Vol. V, Grasses. P. 362-8 hence the name "rip gut".

Similar species

Bromus rigidus ''Bromus rigidus'', the ripgut brome, is a grass native to Eurasia and naturalized in North America. The specific epithet ''rigidus'' means rigid or stiff. Description ''Bromus rigidus'' is an annual grass growing tall. The culms, leaves, and ...

'', known as rigid brome, is very similar in morphology to ripgut brome but differs from the latter in its panicle structure and the callus-scar of its

caryopsis In botany, a caryopsis (plural caryopses) is a type of simple fruit—one that is monocarpellate (formed from a single carpel) and indehiscent (not opening at maturity) and resembles an achene, except that in a caryopsis the pericarp is fused ...

. The two species have some differences in their germination behaviour as well.Kleemann S. G. L. & Gill G. S. 2008. Differences in the distribution and seed germination behaviour of populations of Bromus rigidus and Bromus diandrus in South Australia: adaptations to habitat and implications for weed management. Australian Journal of Agricultural Research 57(2) 213–219 doi:10.1071/AR05200 ''

Bromus sterilis ''Bromus sterilis'' is an annual or biennial species of bromegrass known as barren brome, poverty brome, and sterile brome. Description This is an annual or biennial grass ranging from about 20 to 90 centimeters in maximum height. Leaf blades ...

'', or sterile brome, is similar in most morphological features. It is a slightly smaller plan, an annual or a biennial plant. ''

Bromus hordeaceus ''Bromus hordeaceus'', the soft brome, is an annual or biennial species of grass in the true grass family ( Poaceae). It is also known in North America as bull grass, soft cheat, and soft chess. It is the most common species of ''Bromus'' in Bri ...

'', known as soft brome, is similar in early growth stages with smaller leaf blades. The seed head is an erect panicle, smaller than ''B. diandrus'' with much smaller seeds and much shorter awns.

References

External links

Jepson Manual TreatmentUSDA Plants Profile; ''Bromus diandrus''Photo gallery
{{Taxonbar, from=Q161326 diandrus Bunchgrasses of Africa Bunchgrasses of Europe Flora of North Africa