Hordeum jubatum
Encyclopedia
Hordeum jubatum is a perennials plant species
in the grass family Poaceae
. It occurs wild mainly in northern North America and adjacent northeastern Siberia. However, as it escaped often from gardens it can be found worldwide in areas with temperate to warm climates, and is considered a weed in many countries. The species is a polyploid and originated via hybridization of an East Asian Hordeum
species with a close but extinct relative of Californian H. brachyantherum. It is grown as an ornamental plant
for its attractive inflorescence
s and when done flowering for its infructescence.
's of 6.4 to 9.5. The upper limit of soil NaCl
for productive growth and development is 1.0%. Foxtail barley is also adapted to a wide range of moisture regimes from dry to wet. Although this species is generally found on moist sites, it can withstand drought-like conditions. It is commonly found in lowland areas with restricted soil drainage, disturbed sites, waste areas and fields. Foxtail barley is a pioneer species
or invader in disturbed areas and in areas with high salinity
. It is among the first grasses to establish after disturbance and rapidly invades areas exposed by a receding water table.
and resume growth in early spring, giving Foxtail barley a competitive advantage over many crops. Germination
is inhibited by warm temperatures and seeds require a period of darkness for germination to occur. Foxtail barley is a shallow-rooted plant with germination occurring at soil depths not greater than three inches. The seedling of Foxtail barley first appears as thin, vertical leaves covered in short, dense hairs. The leaves have prominent venation and rough margins, while auricles
are absent or elemental and the membranous ligule
is very short with fine hairs.
breaks into sharply pointed segments with three spikelets composing each segment. Only the central spikelet has one creamy coloured seed while each segment has seven awns with upward pointing barbs. These awns are up to three inches long and become easily attached to animals, clothing, machinery, etc. Leaf blades are slender and a greyish-green colour.
) by lemma awn length. H. brachyantherum has awn lengths of ½ an inch; Foxtail barley has lengths of ½-3 inches; and cultivated barley of 10–15 cm in length. Once Foxtail barley is established, it becomes extremely difficult to eradicate. Its extensive root systems and aggressive habit, as well as its ability to tolerate saline soils make it a resilient competitor. It is considered a weed because of this competitive ability and the dangers it poses to wildlife and livestock. While Foxtail barley may be palatable for animals in early spring before it flowers, its seed heads, when dry, are very harmful to grazing animals. The awns with upward-pointing barbs become easily attached and embedded in the animal's mouth and face, causing severe irritation, abscesses, and even blindness. Foxtail barley is also host to a number of viruses, and because it harbours wheat rust and blackstem rust, can indirectly affect the development of field crops. Since Foxtail barley accumulates high amounts of salt in its leaves and roots, it has the potential of reducing soil salinity. Given Foxtail barley's ability to withstand saline soils, it has been identified as having potential for the revegetation of saline mine spoils to reduce erosion. It has also been recommended as a species suitable for wildlife habitat rehabilitation on disturbed lands, but given its other less desirable traits, other natural grass species would be more beneficial.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
in the grass family Poaceae
Poaceae
The Poaceae is a large and nearly ubiquitous family of flowering plants. Members of this family are commonly called grasses, although the term "grass" is also applied to plants that are not in the Poaceae lineage, including the rushes and sedges...
. It occurs wild mainly in northern North America and adjacent northeastern Siberia. However, as it escaped often from gardens it can be found worldwide in areas with temperate to warm climates, and is considered a weed in many countries. The species is a polyploid and originated via hybridization of an East Asian Hordeum
Hordeum
Hordeum is a genus of about 30 species of annual and perennial grasses, native throughout the temperate Northern Hemisphere, temperate South America, and also South Africa....
species with a close but extinct relative of Californian H. brachyantherum. It is grown as an ornamental plant
Ornamental plant
Ornamental plants are plants that are grown for decorative purposes in gardens and landscape design projects, as house plants, for cut flowers and specimen display...
for its attractive inflorescence
Inflorescence
An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...
s and when done flowering for its infructescence.
Properties
Foxtail barley (Hordeum jubatum) propagates by seed. It is known for its ability to tolerate saline soils but is capable of productive growth on soil types ranging from loamy to clayey soils with pHPH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...
's of 6.4 to 9.5. The upper limit of soil NaCl
Sodium chloride
Sodium chloride, also known as salt, common salt, table salt or halite, is an inorganic compound with the formula NaCl. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms...
for productive growth and development is 1.0%. Foxtail barley is also adapted to a wide range of moisture regimes from dry to wet. Although this species is generally found on moist sites, it can withstand drought-like conditions. It is commonly found in lowland areas with restricted soil drainage, disturbed sites, waste areas and fields. Foxtail barley is a pioneer species
Pioneer species
Pioneer species are species which colonize previously uncolonized land, usually leading to ecological succession. They are the first organisms to start the chain of events leading to a livable biosphere or ecosystem...
or invader in disturbed areas and in areas with high salinity
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
. It is among the first grasses to establish after disturbance and rapidly invades areas exposed by a receding water table.
Seedling
Foxtail barley is a prolific seed producer, with each plant capable of producing upwards of 200 seeds. Seeds are elliptical, yellowish-brown and about a ¼ inch long with four to eight awns. The seeds have sharp, backwards pointing barbs. Seed is dispersed by wind, machinery and animals and germinates in the cooler temperatures of the spring or fall. Seed germinating in the fall can overwinterOverwinter
To overwinter is to pass through or wait out the winter season, or to pass through that period of the year when “winter” conditions make normal activity or even survival difficult or near impossible...
and resume growth in early spring, giving Foxtail barley a competitive advantage over many crops. Germination
Germination
Germination is the process in which a plant or fungus emerges from a seed or spore, respectively, and begins growth. The most common example of germination is the sprouting of a seedling from a seed of an angiosperm or gymnosperm. However the growth of a sporeling from a spore, for example the...
is inhibited by warm temperatures and seeds require a period of darkness for germination to occur. Foxtail barley is a shallow-rooted plant with germination occurring at soil depths not greater than three inches. The seedling of Foxtail barley first appears as thin, vertical leaves covered in short, dense hairs. The leaves have prominent venation and rough margins, while auricles
Auricle (botany)
In botany, an auricle is a small ear-like projection from the base of a leaf or petal....
are absent or elemental and the membranous ligule
Ligule
A ligule — is a thin outgrowth at the junction of leaf and leafstalk of many grasses and sedges or a strap-shaped corolla, such as that of a ray floret in plants in the daisy family....
is very short with fine hairs.
Juvenile/Mature
Foxtail barley is a fibrous-rooted, densely tufted grass that grows from 30 cm to 100 cm tall and is erect or reclining at the base. The stems are erect and smooth and the leaf sheaths are split and hairy. The inflorescence of the mature plant is a dense, long-awned nodding spike with greenish or purplish colouring. The jointed rachisRachis
Rachis is a biological term for a main axis or "shaft".-In zoology:In vertebrates a rachis can refer to the series of articulated vertebrae, which encase the spinal cord. In this case the rachis usually form the supporting axis of the body and is then called the spine or vertebral column...
breaks into sharply pointed segments with three spikelets composing each segment. Only the central spikelet has one creamy coloured seed while each segment has seven awns with upward pointing barbs. These awns are up to three inches long and become easily attached to animals, clothing, machinery, etc. Leaf blades are slender and a greyish-green colour.
Ecological Impact
Foxtail barley is distinguished from cultivated barley (Hordeum vulgare L.) and Meadow barley (Hordeum brachyantherumHordeum brachyantherum
Hordeum brachyantherum, known by the common name Meadow barley, is a species of barley. It is native to western North America from Alaska to northern Mexico, coastal areas of eastern-most Russia , and a small area of coastal Newfoundland....
) by lemma awn length. H. brachyantherum has awn lengths of ½ an inch; Foxtail barley has lengths of ½-3 inches; and cultivated barley of 10–15 cm in length. Once Foxtail barley is established, it becomes extremely difficult to eradicate. Its extensive root systems and aggressive habit, as well as its ability to tolerate saline soils make it a resilient competitor. It is considered a weed because of this competitive ability and the dangers it poses to wildlife and livestock. While Foxtail barley may be palatable for animals in early spring before it flowers, its seed heads, when dry, are very harmful to grazing animals. The awns with upward-pointing barbs become easily attached and embedded in the animal's mouth and face, causing severe irritation, abscesses, and even blindness. Foxtail barley is also host to a number of viruses, and because it harbours wheat rust and blackstem rust, can indirectly affect the development of field crops. Since Foxtail barley accumulates high amounts of salt in its leaves and roots, it has the potential of reducing soil salinity. Given Foxtail barley's ability to withstand saline soils, it has been identified as having potential for the revegetation of saline mine spoils to reduce erosion. It has also been recommended as a species suitable for wildlife habitat rehabilitation on disturbed lands, but given its other less desirable traits, other natural grass species would be more beneficial.