Lapsana communis L.

Global description

Lapsana communis is an herbaceous plant, first disposed in rosette then in developed erect, solitary stem, which branches in the upper part at the time of flowering. It measures up to 1 m high. The stem is angular, hollow and generally glabrous. Simple leaves, alternate, are arranged in a rosette in the young plant. The lower leaves are long-stalked, with oval blade irregularly lobed towards the base, which gradually fades in wing along the petiole and having a large oval to triangular terminal lobe. The upper leaves are sessile, elliptical, lanceolate, becoming smaller. The faces are interspersed with short hairs, the margin is irregularly serrated. The flowers are assembled in yellow heads, fully spread at flowering, at the end of the branches of the inflorescence. The fruit is oblong, flattened, covered with longitudinal ribs, without egret at the top.

Cotyledons

The cotyledons are spatulate to orbicular, 8 mm long and 3 mm wide, with the base closely attenuated in petiole and rounded apex.

First leaves

The first leaves are simple, alternate, arranged in rosette. The leaf blade is held by a long pseudo-petiole, 8 to 10 mm, corresponding to the base of the blade completely attenuated and almost reduced to the midrib. The blade ends with a large terminal lobe orbicular to broadly oval, truncated at the base and rounded apex. The margin is entire to irregularly serrated. The faces are weakly and shortly hispid.

General habit

Herbaceous plant, first in rosette at young stage, then erect, solitary stem, which branches in its terminal part at the time of flowering. It can reach up to 1 m high.

Underground system

Tap root.

Stem

The stem is polygonal, hollow, glabrous, first solitary, then more or less branched in its upper part at the time of flowering. It is smooth, green. It produces a white latex when is cut.

Leaf

The leaves are simple, alternate, and highly variable in shape depending on their position. The base of the leaves are arranged in a rosette, then arranged along the stem. They are carried by a pseudo-petiole, 3 to 6 cm long, corresponding to the attenuation of the base of the blade up to the midrib. The lamina, generally oval oblong in shape, 5 to 10 cm long and 3 to 5 cm wide, is formed from several pinnate lobes in the upper part of the pseudo-petiole then from a large oval terminal lobe. The base of the terminal lobe is truncated, the apex is wide corner. The margin is irregularly serrated, both sides are shortly hispid. The upper leaves are shrinking gradually: they become sessile with elliptical lamina then become lanceolate bracts.

Inflorescence

The inflorescence is a large panicle more or less branched, carrying at the ends of branches yellow capitulum of 1.5 to 2 cm in diameter. The capitulum is underpinned by an involucre of bracts arranged in two rows. The outer bracts are few, oval, lanceolate, 1 mm long. Internal bracts linear oblong, 6 mm long and 1.5 mm wide are keeled when fruiting.

Flower

The florets of the capitulum are all ligulate, few, 8 mm long with shortly serrated top.

Fruit

The fruit is an oblong achene, biconvex, 2.5 to 5 mm long. External achenes are longer than internal. The summit, without pappus, ends with a small ring. The faces are covered with longitudinal ribs. It is light brown in color.

Origin

Lapsana communis is native to Europe.

Worldwide distribution

This species was introduced and naturalized in many temperate or tropical regions of altitude: America (USA, Venezuela, Colombia), Dominican Republic, Haiti, Jamaica, South Africa, in the Indian Ocean in Reunion Island, South Australia, New Zealand, and in the Pacific in Hawaii.

https://www.gbif.org/fr/species/3134857