''Bromus madritensis'' is a species of

brome grass ''Bromus'' is a large genus of grasses, classified in its own tribe Bromeae. They are commonly known as bromes, brome grasses, cheat grasses or chess grasses. Estimates in the scientific literature of the number of species have ranged from 100 ...

known by the common name compact brome. The

specific epithet In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''madritensis'' refers to

Madrid Madrid ( , ) is the capital and most populous city of Spain. The city has almost 3.4 million inhabitants and a metropolitan area population of approximately 6.7 million. It is the second-largest city in the European Union (EU), and ...

Spain , image_flag = Bandera de España.svg , image_coat = Escudo de España (mazonado).svg , national_motto = ''Plus ultra'' (Latin)(English: "Further Beyond") , national_anthem = (English: "Royal March") , i ...

. It has a

diploid number Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respective ...

of 28. There are two subspecies: *''Bromus madritensis'' subsp. ''madritensis'': panicles less dense, stem and leaf sheath less hairy *''Bromus madritensis'' subsp. ''rubens'' (

syn. The Botanical and Zoological Codes of nomenclature treat the concept of synonymy differently. * In botanical nomenclature, a synonym is a scientific name that applies to a taxon that (now) goes by a different scientific name. For example, Linnae ...

''Bromus rubens'') – foxtail brome, foxtail chess, red brome: dense panicles and slightly hairy stems

Description

''Bromus madritensis'' is an winter annual grass, growing solitary or tufted, with erect or ascending culms growing high. The leaf sheaths are downy or slightly hairy. The grass lacks auricles and the glabrous

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 ...

s are long. Its flat leaf blades are either glabrous or slightly hairy, and measure long and wide. The erect and ellipsoid

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 ...

s are long and wide, with short branches that ascend and slightly spread. The branches never droop and bear one or two

spikelet A spikelet, in botany, describes the typical arrangement of the flowers of grasses, sedges and some other Monocots. Each spikelet has one or more florets. The spikelets are further grouped into panicles or spikes. The part of the spikelet that ...

s each. The spikelets are long, longer than the panicle branches, and bear seven to eleven

floret This glossary of botanical terms is a list of definitions of terms and concepts relevant to botany and plants in general. Terms of plant morphology are included here as well as at the more specific Glossary of plant morphology and Glossary o ...

s. The spikelets vary in color from green to distinctly purplish-red. The lightly hairy

glume In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grasses (Poaceae) or the flowers of sedges (Cyperaceae). There are two other types of bracts in the spikelets of grasses: the lemma and ...

s taper at their ends and have translucent margins. The lower glumes are one-nerved and long, and the upper glumes are three-nerved and long. The glabrous and slightly rough

lemma Lemma may refer to: Language and linguistics * Lemma (morphology), the canonical, dictionary or citation form of a word * Lemma (psycholinguistics), a mental abstraction of a word about to be uttered Science and mathematics * Lemma (botany), a ...

s are long. The lemmas are hairier towards their edges and have five to seven veins. The

awn AWN may stand for: * Awn Access to Justice Network in Gaza Strip, Legal Aid Network operate in Gaza Strip, Palestine * Animation World Network, an online organization for animators * Avant Window Navigator, a dock-like bar that tracks open windows ...

s are about the same length, long, and curve slightly. The

anther The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

s are long. The

caryopses 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 ...

are as long as . The grass emerges in early winter and remains dormant until spring when heavy rainfall and higher temperatures stimulate growth. Plants flower from this period typically until May when

water stress Water scarcity (closely related to water stress or water crisis) is the lack of fresh water resources to meet the standard water demand. There are two types of water scarcity: physical or economic water scarcity. Physical water scarcity is where ...

inhibits the grass. Populations grow during periods of heavy rainfall and populations can be wiped out during extended periods of drought. The grass alters soil conditions and the

competition Competition is a rivalry where two or more parties strive for a common goal which cannot be shared: where one's gain is the other's loss (an example of which is a zero-sum game). Competition can arise between entities such as organisms, indivi ...

brought about by the grass both negatively affect native plant populations, and the highly flammable nature of the grass produces wildfires in North American communities where fire was previously rare. Dry

s of the weed entangle themselves in animal hair and can tear at the digestive tracts of foraging livestock.

Habitat and distribution

''Bromus madritensis'' is native to southern and western Europe but has been introduced and naturalized nearly worldwide. In

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

it is found primarily in the western United States, in Oregon, California, and Arizona. The grass was brought to North America in 1848 and was naturalized by the 1890s. In its native range the grass grows in cultivated fields and

steppe In physical geography, a steppe () is an ecoregion characterized by grassland plains without trees apart from those near rivers and lakes. Steppe biomes may include: * the montane grasslands and shrublands biome * the temperate grasslands, ...

s, and in North America it grows in waste areas, road verges, and disturbed areas, in both ranges primarily on dry stony or sandy soil. In California, the weedy grass occurs in areas disturbed by wildfires. It grows from sea level to elevations of .

References

External links

*
Photos: ssp. ''rubens''
{{Taxonbar, from=Q163230 madritensis Flora of Europe Plants described in 1759 Taxa named by Carl Linnaeus