Euphorbia dentata Michx.

Euphorbia dentata plant

Family - Euphorbiaceae

Stems - From a taproot, multiple from the base, branching, erect to ascending, herbaceous, sparsely papillose-hispid and pubescent, to 60cm long(tall), terete, with milky sap. Some of the hairs are multicellular.

Euphorbia dentata stem

Leaves - Mostly opposite, petiolate. Petioles to +1.5cm long, pubescent as the stem, with a shallow adaxial groove. A small cluster of minute glands is often present at the base of each petiole. The glands often brownish. Blades irregularly dentate to subentire, ovate to narrowly lanceolate, to +3cm broad, 8cm long, pubescent above and below, dull green above, bluish green below.

Euphorbia dentata leavesPressed leaves.

Inflorescence - Terminal bracteate cluster of cymules. Pedicels to 1.5mm long, glabrous.

Euphorbia dentata inflorescenceInflorescence.

Flowers - Involucre (at anthesis) whitish-green, 3mm long, glabrous, 5-lobed, with a single cupulate nectary, (nectary green, to 1.2mm long). Lobes fimbriate and often with a pinkish tinge. Ovary green, glabrous, 1.2mm in diameter (at anthesis). Styles 3, white, glabrous, spreading, to 1mm long, divided nearly to the base and appearing as 6. Anthers bi-lobed, yellow, .5mm broad. Filaments white, glabrous, distinctly jointed in the apical 1/4. Stamens +/-30 per flower. Capsules 3-lobed, glabrous, 3-seeded.

Euphorbia dentata flowersFlowers.

Flowering - July - October.

Habitat - Prairies, glades, waste ground, disturbed sites, roadsides, railroads.

Origin - Native to U.S.

Other info. - This species is found throughout Missouri. The plant is fairly inconspicuous because of its indistinct flowers.
It is closely related to the every popular Poinsettia that many people like to buy around the winter holidays.
Be careful with the sap of this plant and most from this genus and it can be irritating to the skin and eyes.

Photographs taken in Ellington, MO., 7-7-03.


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