Dactylis glomerata

Morphological description

Perennial herbaceous plant, tufted and robust, with an erect or slightly curved posture at the base, reaching a variable height from 30 up to 120-140 cm. The culms are characteristically compressed and rigid at the base, with a smooth and green-grayish surface, sometimes glaucous. The roots are fasciculate and well developed, giving the plant good stability in the soil.

The leaves have a linear blade, 4 to 8 (up to 10) mm wide, herbaceous green in color, often channelled or flat, with the upper surface slightly rough due to the presence of scattered hairs, while the lower surface is smoother and shiny. The ligule is a small oblong-truncate membrane, 2-10 mm long, without lateral auricles, often torn. The leaf sheaths are compressed and keeled (with a marked keel).

The inflorescence is an erect panicle, with a triangular or ovate outline, 3 to 15 cm long, composed of 1-2 basal spaced branches, rigid and flattened, which are bare in the lower part and bear dense unilateral spikelet clusters at the top. The spikelets are 5-9 mm long, laterally compressed and formed by 3-7 flowers; the clusters are very dense and compact, giving the panicle an agglomerated and characteristic appearance.

The glumes are coriaceous, subequal, 3-3.5 mm long, often green or violet in color, with a ciliate or hirsute keel and a mucronate or acuminate apex; the lower one is one-nerved, while the upper one is three-nerved. The lemmas are membranous, with 5 evident veins and ciliate along the keel. The paleas are about as long as the lemmas. The anthers are yellow or violet, 2 to 4 mm long.

The fruit is a small awned caryopsis, oblong-ovate with a channelled inner face.

The species shows high morphological variability, due to its polyploid complex, with predominantly tetraploid populations (2n=28), but also diploid and hexaploid. This variability is reflected in leaf size, hairiness, and the general appearance of the panicles.

Habitat and distribution

It is a mesophilous species, widely distributed in Italy and the Mediterranean area, present from the lowlands up to about 2000-2500 meters altitude. It prefers anthropized environments such as mown meadows, pastures, roadsides, uncultivated areas, forest edges, and hedgerows, on nitrogen-rich and well-drained soils.

In Italy it is common in mountainous and hilly regions, but also adapts to less natural habitats, being a synanthropic species closely linked to agricultural and grazing activities. In more intact natural contexts it is often replaced by related species such as Dactylis hispanica and Dactylis polygama, with which it can give rise to intermediate populations.

In the Mediterranean region it is also widespread in temperate Europe, Western Asia, and North Africa, where it colonizes meadows, pastures, and forest margins, showing remarkable ecological plasticity.

Flowering period

Flowering generally occurs between April and September, with a possible extension until October, depending on altitude and latitude. In more temperate and lowland areas flowering starts early in spring, while in mountainous environments it can extend until late summer.

Ecology and pollination

The species is anemophilous, with flowers lacking colored petals but with prominent anthers of violet or yellowish color that facilitate pollen dispersal by wind. The dense and compact spikelets favor the protection of flowers and fruits. Seed dispersal occurs through awned caryopses that can be transported by wind or animals.

As a forage plant, it is highly appreciated by livestock for its high nutritional value and persistence over time, contributing to the ecological balance of cultivated pastures.

Curiosities and traditional uses

This species, commonly known as erba mazzolina or dattile, is one of the most important forage grasses at the European and Mediterranean level. It is cultivated and managed for hay production and as quality pasture, thanks to its longevity and nutritional richness.

It is subject to parasitism by the fungus Claviceps purpurea, known as "ergot of rye," which can cause the formation of black sclerotia on the spikelets, a fungal disease with significant impacts on the quality of forage crops.

No significant ethnobotanical traditions or medicinal uses are known specifically linked to this species, but its main value lies in agricultural use and the conservation of meadow ecosystems.

Etymology

The genus name "Dactylis" derives from the Greek "dáktylos," meaning "finger," referring to the shape of the panicles that resemble the phalanges of a finger. The specific epithet "glomerata" indicates the characteristic agglomerated and compact arrangement of the spikelets at the apex of the panicle.

The Italian common name "erba mazzolina" precisely recalls this aspect of "bundles" or dense tufts of flowers, while "dattile" is an older toponym, probably linked to the shape or traditional use of the plant.

Sources

• Prof. S. Pignatti, "Flora d’Italia"
• Acta Plantarum - Flora delle regioni italiane (scheda di Anja Michelucci)
• Tela Botanica / H. Coste, "Flore descriptive et illustrée de la France"
• World Flora Online (WFO)