Euphorbia hyssopifolia L.

Global description

Euphorbia hyssopifolia is an annual herbaceous plant, erect, branched dichotomously, with a height up to 40 cm tall; white latex. Leaves opposite, elliptical linear. It grows in fallows, fields, roadsides, beaches.

Cotyledons

The cotyledons are short petiolate, ovate with base and apex rounded.

General habit

Plant usually erect, with filiform branches measuring 10 to 40 cm high. Presence of latex.

Underground system

The main root is a taproot.

Stem

The stem is erect but sometimes spreading, reddish, totally glabrous, cylindrical and articulated, the internodes are distant of about 5 cm. It ramifies  in a dichotomous way. Presence of white latex.

Leaf

The leaves are simple, opposite, glabrous, glaucous green, a little paler beneath, sessile to subessile. They are distant from one pair to another. Stipules widely triangular with bifid lobes laciniated, ciliate. Petiole glabrous, 1-1.5 mm long. The blade is often kidney-shaped, oblong to ovate-elliptical, 10 to 35 mm long and 5 to 10 mm wide. The base is asymmetric, the top is widely cunate, the margin is finely toothed. Both sides are glabrous. 3 to 5 palmate veins, ascending and arching are clearly visible on the upper surface. The leaves of the flowering twigs are narrower.

Inflorescence

The inflorescence is an axillary or terminal cyme, with distichous ramifications. It is loose and leafy.

Flower

The flowers are greenish consisting of a small involucral cupule (cyath), short pedicellate and glabrous. The edge of the cup has 4 fleshy, rounded glands spread horizontally white or red with a small green ball at the base. In the center of the cup is a female flower reduced to a large ovary with 3 cells, long pedicelled hanging on the outside of the cup. It ends with a bouquet of 3 bifid stigmas. 3 to 5 stamens white filet and bifidous and rounded anthers (male flowers reduced to 1 stamen) emerge from the cupule.

Fruit

The fruit is a trilocular, glabrous, strongly denuded capsule 2 to 2,5 mm in diameter, containing three seeds.

Seed

The seed is black or greenish, ovoid tetragonous 1,1 mm long and 0,8 mm in diameter. The dorsal surface presents 2 to 3 transverse wrinkles.

Origine

Euphorbia hyssopifolia is native to tropical adn subtropical regions of the American continent.

Worldwide distribution

This species is present throughout tropical and subtropical America, from the south of the USA to the south of Brazil. It is also present in West and East Africa, in the Indian Ocean in Madagascar and in the Seychelles, on the west coast of China, in Australia and in the Pacific islands.

https://www.gbif.org/species/3065912