Bromus hordeaceus

Morphological description

It is an annual herbaceous plant, belonging to the family Poaceae, reaching a height between 30 and 80 cm. The habit is erect but with culms (stems) that are often bent or flexed at the base, ascending and generally solitary. The stem surface is characterized by slight pubescence, especially below the inflorescence, while the nodes of the culm are finely hairy.

The leaves are alternate, with a linear and flat blade, 3 to 7 mm wide, equipped with a surface both upper and lower covered by fine hairs. The texture is herbaceous and the leaf has entire margins. The leaf sheath is closed and pubescent, while the ligule is short (about 1 mm), acute and sometimes fringed.

The inflorescence is a dense, contracted, ovoid panicle, 5 to 15 cm long. The panicle branches are short and rough, with pedicels shorter than the spikelets which are pubescent. The spikelets, 12 to 20 mm long and 4-6 mm wide, contain from 4 to 16 flowers, with the more distal ones often sterile. The glumes are unequal, membranous with pubescent margins, the lower glume measures 4-6 mm and is grooved by 3-5 nerves, while the upper glume is longer (5-8 mm) with 5-7 nerves. The lemma, elliptical in shape and 8-11 mm long, is pubescent and has 7-9 well-defined nerves; the apex is obtuse, slightly bifid, with a robust awn inserted 1-2 mm below the tip and reaching a length of 5 to 10 mm, straight and rigid. The palea is shorter than the lemma, with two nerves and ciliate margins. The anthers are small, from 0.2 to 1 mm.

The fruit is a caryopsis, which can be shorter or the same length as the palea, typical of grasses.

Habitat and distribution

This species grows widely throughout the Italian territory, from the plains up to the mountain and subalpine belt, particularly in hilly and not too high mountainous environments. It prefers disturbed habitats, such as cultivated lands, road edges, field margins, embankments and fertilized meadows. Its presence is common in areas with fresh, well-drained soils rich in organic matter, with predominantly sunny or semi-shaded exposure.

In the Mediterranean basin it is found with a similar distribution, adapting to anthropized and semi-natural habitats, where competition with other herbaceous species is reduced.

Flowering period

The hairy brome typically flowers between May and July, with possible extension of flowering depending on altitude and local climatic conditions. In warmer and low altitude areas flowering can start as early as May, while in cooler mountain environments it extends until July.

Ecology and pollination

The species is predominantly wind-pollinated, like many grasses, and does not have petals or conspicuous colors to attract pollinating insects. The structure of the spikelets, with robust and long awns, favors seed dispersal, which can adhere to animal fur or be carried by the wind, facilitating colonization of new habitats.

Adaptation to disturbed soils and anthropized ecosystems makes it an important component of secondary herbaceous communities, contributing to soil stabilization and local biodiversity.

Curiosities and traditional uses

No significant traditional medicinal or food uses are documented for this species. However, the common name "forasacco" recalls the characteristic of the achenes (seeds) equipped with a pointed and rigid awn, which can easily penetrate the skin or fur of animals, causing discomfort. This has led to some ethnobotanical interest in recognizing and managing infestations of this plant in pastures and cultivated lands.

Etymology

The scientific name of the genus, Bromus, derives from the Greek bromos, meaning “fodder”, indicating the importance of numerous species of this group as forage grasses. The specific epithet hordeaceus refers to the barley-like appearance (Hordeum), recalling the shape and structure of the inflorescences.

The Italian common name "forasacco peloso" highlights the presence of hairs on various parts of the plant and the characteristic pointed awn of the seeds ("forasacco" literally means “that pierces the sack” or penetrates the skin, metaphorically referring to the irritating potential of the seeds).

Sources

• Prof. S. Pignatti, "Flora d'Italia"
• World Flora Online (WFO)