Hordeum murinum: Description and Etymology
hordeum murinum, popularly known as mousetrap barley, harem pants, mouse tail, spikelet o mouse barley, is an annual grass belonging to the family poaceae. The generic name Hordeum comes from ancient Latin to designate barley, while the epithet murinum, derived from Latin Murinus, literally means 'mouse', probably in reference to the appearance or color of its spikes, which resemble the fur of these rodents.
This species, widely distributed and recognizable in urban and rural environments, stands out for its rapid adaptation to habitats altered and their continued presence near human settlements.
Taxonomic classification of Hordeum murinum
- Domain: eukarya
- Supergroup: Archaeplastida
- Phylum: Chloroplastida
- Division: Streptophyta
- Subdivision: Spermatophytina
- Class: Magnoliopsida (or Liliopsida, according to different classifications)
- Order: poales
- Family: poaceae
- Subfamily: pooideae
- Tribe: Triticeae
- Gender: Hordeum
- Species: hordeum murinum
Nota: Taxonomic classification may vary slightly depending on the source and is subject to continuous revision, but the main categories remain standardized in current botany.
Detailed botanical description
hordeum murinum is a annual plant It completes its entire life cycle in a single favorable season, surviving the rest of the year as a seed. It exhibits the following key morphological traits:
- Stems: Usually erect o ascendants, glabrous, hollow and spongy, with well-marked internodes. The height can reach up to 32 centimeters or more, depending on conditions.
- Sheets: Arranged alternately, with villous sheath (covered in hair), ligule truncated and limbo long, loosely hairy or rarely glabrous.
- Inflorescence: Present a dense, brittle, cylindrical spike, considered a direct extension of the stem. The spike is made up of groups of three spikelets per node: the central one is bisexual, and the lateral ones are male or sterile, with only anthers.
- Spikelets: Single-flowered (monochlamydia), the lateral ones have a peduncle while the central one can be sessile or pedunculated. All show glumes linear, long-winged and scabrid, often ciliate on the margins, especially on the upper part of the spike.
- Arestas: Bracts with elongated tips forming rough, characteristic edges, responsible for the rough feel and the ability to adhere to surfaces.
- Fruit: Of type caryopsis, that is, a typical grain of grasses.
It is relevant to highlight the difficulty in morphological differentiation of its subspecies or varieties: H. glaucum, H. murinum y H. leporinum, with very similar characteristics and coexisting in the same habitat.
Habitat and ecology
hordeum murinum It is a species highly adapted to ruderal environments or those altered by human activity. Its typical habitats include:
- Roadsides and roads.
- ditches, vacant lots, urban lots and rubble areas.
- Borders of fields and meadows, where it sometimes competes with grasses of greater forage value.
- Also appears in artificial turf and poorly maintained gardens, taking advantage of their tolerance to drought and soil disturbances.
The plant communities where it is most representative belong to the Order Sisymbrietalia officinalis (Class Ruderali-Secalietea), sharing space with species such as Ammi majus, Bromus rigidus, Erucoid diplomaxis y Sisymbrium officinale.
Ecological preferences: It is mainly developed in dry soils o slightly damp, rich in bases (pH between 5,5 and 8), and prefers sunny areas, not tolerating prolonged shade or the presence of salts. It is an indicator of moderately dry soils rich in nutrients, especially nitrogen.
The species shows great resistance to soil disturbances, such as plowing or surface tillage, and is capable of rapidly recolonizing disturbed areas thanks to its high seed production and efficient dispersal.
Geographical distribution
hordeum murinum It is a plant with cosmopolitan distribution in temperate regions, being especially abundant in:
- Europe: Practically the entire continent.
- Asia: Temperate and Mediterranean zones.
- Africa: Northern regions and some subtropical zones.
- America: From Canada to countries in the Southern Cone, including its distribution in Central and South America.
Its presence near human settlements and on cultivated land has made it one of the most common and widespread spontaneous grasses, and can be found in both rural and urban environments.
Phenology and reproduction
hordeum murinum It has an annual life cycle and its flowering extends mainly during spring and summer, although it can be prolonged depending on the climatic and geographical conditions. The plant germinates at the end of winter or beginning of spring and flowers from April to August.
- reproductive cycle: It completes its reproductive development in a single season. Seed dispersal depends largely on wind, animals, and human activities, allowing for rapid and efficient colonization.
- Seeds: De average weight 9,3 mg Each of these species exhibits nonspecific local dispersal strategies, reaching distances greater than 0,3 meters. Seeds commonly adhere to clothing, animal tissues, and agricultural machinery.
- Biological type: Therophyte, that is, an annual plant that survives unfavorable periods only in the form of seeds.
This strategy allows you to successfully deal with disturbed areas or those subjected to regular agricultural work.
Ecological indicators and adaptation to the environment
hordeum murinum is used as ecological indicator of certain environmental conditions:
- Light: Highly intolerant of shade; grows effectively in open, sunny areas.
- Salinity: It does not tolerate saline soils.
- Humidity: Prefers dry soils, although it can survive in slightly humid conditions.
- Acidity: It prefers basic soils, with a pH range of 5,5 to 8.
- Nitrogen: Indicator of soils rich in nutrients, especially nitrogen.
Its persistence and expansion in different habitats are linked to its ability to take advantage of soil disturbance, whether due to agricultural work, construction, animal trampling, or other anthropogenic causes.
Interaction with humans and other species
Today, hordeum murinum is considered bad weed or adventitious in crops and pastures, since its presence can reduce the quality of the forage and compete with species of agricultural interest.
- Relationship with livestock: It is not usually consumed voluntarily by livestock due to the hardness and roughness of its edges, which can cause oral irritation and injuries in domestic animals, especially in dogs and cats if the spikes get into ears, nostrils or skin.
- Ecological role: Although it is often attempted to eradicate it, it plays an important role as a pioneer in the colonization of disturbed soils and as protection against erosion.
- Human influence: Human activity favors their dispersal, as agricultural machinery, clothing, or the fur of domestic animals inadvertently transport the seeds.
Mode of seed dispersal
La dispersion strategy de hordeum murinum It is primarily local and nonspecific, although it can be transported over longer distances by human or animal activity. The sharp edges of the spikes facilitate the seeds' attachment and travel on textiles, wool, and animal skins, as well as on footwear and agricultural machinery.
The ability of humans to disperse is one of the keys to their success as a colonizing species and their abundant presence in all types of rural and agricultural environments.
Varieties and subspecies of Hordeum murinum
Within hordeum murinum there are several subspecies and varieties which, although difficult to distinguish in the field, present some morphological and ecological differences:
- hordeum murinum there. glaucum
- hordeum murinum there. leporinum
- hordeum murinum there. montanum
- hordeum murinum there. murinum
- hordeum murinum there. stariurum
In addition, there are synonyms related to historical nomenclature and classification, such as Triticum murale, Critesion murinum y Zeocriton murinum.
Vernacular names in different languages
- Spanish: Mousetail, spikelet, mouse barley, mousetrap barley, wild barley, spikelet.
- English: Mouse barley, wall barley, hare barley, smooth barley.
- Portuguese: Barley twice.
- Galician: Orxo.
- Catalan: Margall bord.
- In Patagonia: Foxtail.
Agricultural and phytosanitary importance
hordeum murinum has been considered a bad weed problematic in agricultural systems, as it competes for resources with cultivated species and can harbor diseases.
Cereal blight It is one of the diseases historically associated with grasses such as mousetrap grass. Caused by fungi of the genus Ustilago, which affects oats, wheat, barley, triticale, and rye. The fungus is transmitted as a dormant mycelium in the grain, developing spores that destroy the floral organs of the host plant. Infected plants show reduced stature, reduced tillering, and visible symptoms at heading. Wind favors spore dispersal, making control difficult in agricultural fields.
Traditional agronomic management includes crop rotation, frequent mowing and seed cleaning to minimize the impact of weeds and diseases associated with hordeum murinum.
Historical and cultural uses of mousetrap barley
Although its economic value is currently low and it is considered harmful in the agricultural and livestock sectors, mousetrap barley has had some curious uses:
- Traditionally, spikes They were used in children's games, thrown as 'arrows' due to their ability to adhere to fabrics and animal hair.
- In folk medicine and ethnobotany, its use is anecdotal and very limited, since it is not suitable for direct human or animal consumption.
Role in ecosystems and plant communities
hordeum murinum plays an important role in the dynamics of ruderal communities and degraded grasslands. It protects the soil from erosion and contributes to the stabilization of slopes and roadsides. It can also serve as a refuge for small invertebrates and as an indicator of the degree of environmental disturbance.
- It favors the ecological succession in areas devoid of vegetation due to mechanical disturbances, fires or overgrazing.
- It participates in associations with other nitrophilous and pioneer species until the plant community evolves towards more stable and biodiverse stages.
Environmental disturbance factors
La mowing frequency and grazing pressure significantly influence the presence and expansion of hordeum murinumHerbivorous pressure primarily involves grazing by large mammals, both domestic and wild. In humid habitats, birds may intervene, although grazing by invertebrates and small vertebrates is less significant.
La soil disturbance, caused by plowing, traffic and construction, also favors the proliferation of this species, which thrives where other grasses are displaced.
Phytosociological and conservation indicators
hordeum murinum It is a characteristic element of communities subnitrophilous from temperate zones, representing an excellent indicator of altered, nutrient-rich soils. It is not part of the protected flora nor is it considered a threatened species, but its monitoring is useful in biodiversity studies, restoration, and environmental assessment.
La mousetrap barley It is a key species for understanding the dynamics of humanized ecosystems and the adaptation of flora to disturbances. Its presence accompanies the evolution of agriculture and urbanization, demonstrating an astonishing capacity for colonization and survival in changing environments.