Spergula arvensis L.

Global description

Spergula arvensis is a small annual branched herb, glabrous or more or less with glandular hairs, prostrate or erect, maximum 70 cm high. The leaves, simple and opposite linear, are traversed by a longitudinal groove on the underside. They are grouped into pseudo-whorls stepped on the stem. The inflorescence is a terminal panicle of small white flowers whose filiform pedicels refract and lengthen after fertilization. The fruit is a globular capsule with 5 valves, which contains up to 25 spherical seeds, surrounded by a ring of black color.
 
Cotyledons

The cotyledons are linear (10 to 15 mm long) of cylindrical cross section (less than 1 mm diameter).
 
First leaves

The two first leaves are perpendicular to the cotyledons and inserted at their level. The subsequent leaves are also inserted at the same level, forming a rosette of whorls leaf. The stem then elongates and forms a second whorl.
 
General habit

Annual herb branched from the base, prostrate or erect, measuring 20 to 70 cm high.
 
Underground system

Taproot system.
 
Stem

The stem with cylindrical section (2 to 3 mm in diameter) is glabrous or have glandular sparse hairs.
 
Leaf

The leaves opposite and simple, are arranged in pseudo-whorls. They are sessile, with scarious large stipules at their base. The lamina is linear acuminate, 1 to 4 cm long and 0.5 to 0.75 mm wide, is covered with a longitudinal groove on the underside. Its surface is almost glabrous or with sparse pubescence of glandular hairs.
 
Inflorescence

The flowers are arranged in irregular cymes forming a terminal panicle. The inflorescences often has glandular hairs.
 
Flower

The pedicel is slender, longer than the calyx. It refracts after fertilization and lengthens during fruiting. 5 sepals, ovate with obtuse tip (3.5 to 4 mm long and 1.5 to 2.25 mm wide) are green with white edges. The five petals, white, oval to oblong, obtuse end, are roughly the same size as the sepals. The stamens, divided into two series, are usually 10 in number. Sepals, petals and stamens are inserted on a glandular ring. The ovoid ovary has 5 styles situated alternately with the sepals.
 
Fruit

The fruit is an ovoid or sub spherical capsule with 5 valves, slightly exceeding the calyx. It may contain up to 25 seeds.
 
Seed

The seed (1 to 1.2 mm in diameter) is sub globose, surrounded by a narrow rim, tuberculate surface, black in color.

Origin

Spergula arvensis is native to Europe, the Mediterranean basin and India.
 
Worldwide distribution

Europe, Middle East, Central Asia and China, India, Pakistan, Eastern and Southern Africa, North America, South America, reported in Australia and the Pacific Islands.
 

https://www.gbif.org/fr/species/3085810