Cyperus capitatus

Morphological description

Perennial herbaceous plant, Zigolo delle spiagge has an erect habit and variable dimensions between 10 and 50 cm in height. The stem is cylindrical, glabrous, glaucous green in color, not hollow and sometimes slightly curved at the base. The leaves, arranged alternately along the stem, are linear, rigid, grooved and curved, with a closed sheath and lacking stipules; their width ranges from 2 to 6 mm and their length often exceeds that of the stem.

The root system consists of a well-developed, deeply thickened and long rhizome that extends horizontally beneath the sandy surface. The rhizome is covered by scales and wrapped in brown fibers, characteristics that favor the plant’s stability in the mobile substrates typical of coastal environments.

The inflorescence is a distinctive element: it appears as a subspherical capitulum, solitary and terminal at the apex of the stem, with a diameter of 2-3 cm. It is formed by numerous reddish-brown spikelets, each composed of 4 to 12 flowers, closely grouped. The inflorescence is wrapped by 3-6 large, horizontal and patent leafy bracts, unequal in size, with revolute and sub-spinose margins, 3 to 12 cm long and widened at the base. The spikelets are oblong or lanceolate (8-20 mm in length and 3-4 mm in width), with glumes from ovate to lanceolate, mucronate and with scarious margins. The flowers lack petals and are green in color, with 3 stamens equipped with long dilated filaments and 3 stigmas.

The fruit is a trigonous achene, coriaceous and indehiscent, about one third the length of the glume, which allows seed dispersal. The absence of petals and the compact structure of the inflorescence are adaptations to the specific environmental conditions of the coastal habitat.

Habitat and distribution

The species is typical of Mediterranean sandy coasts, with a steno-Mediterranean range mainly limited to the coastal belt. In Italy it grows on sandy beaches and in the first coastal dunes, in well-preserved marine environments characterized by mobile and arid substrates. The plant prefers sandy, permeable soils, subject to wind action and saline influence, conditions that make survival difficult for many other plant species.

In the Mediterranean area, it is found along the coasts of France, Corsica and other regions facing the Mediterranean Sea. Its presence is closely linked to the stability of coastal dunes, where it plays a fundamental role in soil consolidation thanks to its extensive and robust rhizome.

The growth altitude is generally low, limited to coastal zones, where the plant is exposed to full sun and the typical climatic conditions of marine beaches.

Flowering period

Flowering occurs between May and September, with some possible variation linked to local climatic conditions. Generally, the species flowers in late spring and summer, a period during which climatic conditions favor flower maturation and subsequent fruit production.

Ecology and pollination

Zigolo delle spiagge adapts to extreme environmental conditions, such as intense heat, high salinity and constant wind typical of the Mediterranean coastal belt. The plant has a limited transpiring surface, also thanks to the sunken stomata, which reduces water loss and improves drought resistance.

Pollination is predominantly anemophilous, i.e., wind-mediated, given the compact structure and lack of showy petals of the flowers. The shape of the inflorescence and the presence of long stigmas increase the efficiency of pollen capture transported by the air.

Seed dispersal occurs through the coriaceous achenes, which remain indehiscent and can be transported by sand and wind along the coasts, facilitating colonization of new dune areas.

Curiosities and traditional uses

No medicinal, food or particular ethnobotanical uses related to this species are known. Its importance is mainly ecological, as it contributes to the consolidation of coastal dunes and the stability of the sandy habitat, particularly vulnerable to erosion.

Etymology

The genus name Cyperus derives from the Greek "kýpeiros", meaning angular rush, referring to the shape of the plants of the genus. The specific epithet capitatus comes from the Latin caput, capitis (head), and refers to the compact capitulum shape of the inflorescence, similar to a small head or flowering head.

The Italian common name, Zigolo delle spiagge, recalls the sandy coastal habitat where the plant is typically found, with “zigolo” being a term used for some Cyperaceae species with a similar habit.

Sources

• Acta Plantarum - Flora delle regioni italiane (actaplantarum.org)
• Acta Plantarum - Scheda di Giuliano Salvai
• Tela Botanica / H. Coste, Flore descriptive et illustrée de la France