Hyoseris radiata

Morphological description

Perennial herbaceous plant belonging to the family Asteraceae, characterized by a compact habit and a height ranging between 10 and 40 cm. The root system is robust and thick, serving as anchorage and reserve, from which a basal rosette of leaves arranged in a radial pattern develops at ground level.

The leaves are petiolate, pinnatisect or runcinate in shape, with lateral segments varying from 7 to 8 per side, extending up to half of the leaf blade. These segments, arranged progressively wider from the base towards the apex, are often directed downwards and partially overlapping. The texture is herbaceous, with serrated margins; the surface, especially on the lower side along the central vein, is generally covered with stiff and spreading hairs, although glabrous variants are present in coastal populations. Leaf dimensions vary approximately between 2-2.5 cm in width and 10-14 cm in length, while the petiole is about one eighth to one fifth the length of the blade.

The flowering scapes are erect, leafless (aphyllous) and generally undivided, with a more or less rough surface. On top of them develop the capitula, solitary and with a diameter between 4 and 4.5 cm. The involucre is cylindrical-campanulate, formed by 5-8 lanceolate bracts arranged in two rows: the inner ones, larger (10-15 mm), are lanceolate, while the outer ones, smaller (4-5 mm), are ovate. The inner bracts are reinforced by 3 smaller outer bracteoles, about one third the length of the former.

The flowers are ligulate, with numerous yellow petals arranged actinomorphically, i.e., symmetrically around the center, forming a radial pattern that gave the plant its common name. The outer ligules are between 15 and 17 mm long, 3-4.5 mm wide, often greenish and reddened at the base, while the inner flowers are progressively smaller and completely yellow in color. The fruits are cylindrical-angular achenes, compressed, brown in color, 8 to 11 mm long, with a pappus of linear bristles (7-11 mm) that largely exceed the involucre of the capitulum. The central achenes are ciliate on the edge, while the peripheral ones are sterile and shorter.

The species shows significant morphological variability, especially regarding leaf pubescence, which can range from completely glabrous individuals to strongly rough ones even within the same population. Some coastal populations, such as those of Sardinia and Pantelleria, have almost completely glabrous leaves and entire lateral segments with rounded apex, features that in the past suggested a taxonomic distinction.

Habitat and distribution

This species is widespread in Mediterranean areas, with a range known as the "olive area," which includes Mediterranean coasts and adjacent zones. In Italy it is mainly present in coastal and submontane regions, with a distribution extending from sea level up to about 1000 meters altitude. It typically grows in uncultivated grassy habitats, on walls, stony paths, and soils with calcareous substrates, preferring sunny exposures and mountainous or hilly environments.

The plant is adapted to well-drained and calcareous-rich soils and is often found in anthropized or semi-natural environments, such as uncultivated lands and transition areas between cultivated and natural zones.

Flowering period

Flowering extends practically throughout the year, with a higher concentration from January to December, without significant seasonal interruptions in the milder Mediterranean environments. The long flowering phase allows a continuous presence of yellow flowers visible on the plant, facilitating reproduction and pollination.

Geographical variations may influence the intensity and duration of the flowering period, especially in areas with harsher or less favorable climates.

Ecology and pollination

The plant reproduces mainly sexually through seeds, which are dispersed by the wind thanks to the feathery pappus that facilitates long-distance dispersal. Pollination is entomogamous, favored by pollinating insects attracted by the bright yellow flowers and their ligulate and radiate arrangement.

The main pollinators are insects belonging to groups such as bees, butterflies, and other generalist pollinating insects frequenting Mediterranean grassy environments. The absence of foliar bracts on the scapes and the solitary arrangement of the capitula make the flowers easily accessible to insects.

Curiosities and traditional uses

This species is recognized as edible and medicinal, with traditional use in food and folk medicine. Young leaves are used raw in mixed salads, often combined with aromatic plants such as pimpinella and wild fennel, or cooked in soups. They are also used as filling for tortelli, enhancing their slightly bitter flavor.

Historically, the plant is included in the list of “alimurgic” plants, i.e., wild plants used as food in times of famine or war, testimony to its nutritional value and availability in the Italian countryside.

No specific pharmaceutical applications are well documented but the species, like other Asteraceae, has traditionally been used for its medicinal properties in popular contexts. It is important to emphasize that such uses are purely informative and do not replace medical or therapeutic advice.

Etymology

The scientific name derives from the Latin “hus” or “huios” meaning “pig” and “seris” or “seridos” indicating a “salad.” The term refers to the resemblance of the leaves or flowers to edible plants traditionally known as wild salads, to which a name related to food use for livestock or humans was also attributed.

The Italian common name “radicchio raggiato” alludes to the arrangement of the ligulate flowers arranged radially within the capitulum, highlighting the characteristic sunny and bright shape of the flower.

Sources

• Prof. S. Pignatti, Flora d'Italia
• Acta Plantarum - Flora delle regioni italiane (sheet by Nino Messina)