Mexican fireplant – Euphorbia heterophylla

Stem is simple or branched, cylindrical, hollow, glabrous to sparsely pilose at apex. Leaves are of variable shape and size, linear-lanceolate to oval, margins entire or irregularly toothed, glabrous to pilose. The lower leaves are long-petiolate and alternate. Upper leaves are sessile and opposite or whorled, forming a cluster of bracts, often with a pale patch at the base, subtending the terminal inflorescence. The inflorescence consists of a dense cluster of small, short-stalked cyathia. Each cyathium comprises a cup-shaped involucre with inconspicuous male flowers producing a single stamen only, a female flower without sepals or petals, and a stalked nectar gland with round opening. Fruit is dehiscent, 4-6 mm in diameter, yellowish-green, three-lobed and explodes when ripe, dispersing seeds 1 m or more from the parent plant. Seeds are black, conical, 2-3 mm long. All plant parts have milky latex.