Flowering Spurge

This herbaceous perennial plant is ½–3' tall, producing one or more stems that are unbranched, except at their apices, where the inflorescences occur. Each stem is light green, terete, glabrous, and sometimes glaucous (rarely it is pubescent). Alternate leaves occur along the entire length of each stem, except at the apex underneath an inflorescence, where the uppermost leaves occur in a whorl of 3 or more. They are widely spreading to ascending. Individual leaves are up to 2½" long and ½" across; they are linear-oblong to oblong in shape and their margins are entire (toothless). The tips of these leaves are blunt, while their bases are sessile or nearly so. The upper and lower leaf surfaces are light gray-green to medium green and glabrous (rarely the lower leaf surface is pubescent). Leaf venation is pinnate with prominent central veins. The foliage of this plant contains a toxic white latex.

Each mature stem terminates in a panicle of flowers up to ¾' long and 1' across. This panicle is somewhat flat-headed and it has an open airy appearance. Individual flowers span about ¼" across (including their petaloid bracts). Each flower has a tiny cup-like cyathium containing the reproductive organs, 5 white petaloid bracts, and 5 green glandular appendages at the bases of these bracts. Because Flowering Spurge is monoecious, separate male (staminate) and female (pistillate) flowers are produced on the same plant. Each male flower has several stamens, while each female flower has an ovary with a tripartite style. The petaloid bracts are obovate in shape; sometimes they are slightly notched at their tips. The branches and pedicels of the inflorescence are light green, glabrous, and terete; pairs of small leafy bracts up to ½" long occur at the bases of pedicels and where the branches divide. The blooming period occurs from early summer to early autumn, lasting about 1-2 months for a colony of plants. There is no floral fragrance. During this time, an entire plant may lean to one side because of the weight of its inflorescence. Afterwards, the female flowers are replaced by 3-celled capsules of seeds that are 3-4 mm. long, globoid, and 3-lobed in shape; there is one seed for each cell of a capsule. At maturity, these capsules split open to eject their seeds. The seeds are 2-3 mm. long, ovoid-obovoid in shape, and finely mottled. The root system consists of a taproot that becomes woody with age.