spotted spurge

not listed

N5 - Secure

SNR - Unranked

not listed

FACU - Facultative upland

FACU - Facultative upland

FACU - Facultative upland

Spotted spurge is a prostrate, usually less than 1″ tall, annual forb that rises from a slender taproot. It forms a circular mat. All parts of the plant emit a milky sap when broken.

The stems are thick, round, up to 16″ long, and frequently branched at the base. They become red in strong sun. Young stems and are densely hairy, older stems less so. The plant does not root at the nodes.

Leaves are opposite, oblong or oblong egg-shaped to linear-oblong, often widest below the middle. They are 3 ⁄16″ to ⅝″ long, and a third to half as wide. They are rounded at the tip, rounded and asymmetrical at the base. They are on leaf stalks up to 1 ⁄16″ long. The upper surface is deep green, often with a reddish spot near the middle. The reddish spot is the source of this plant’s common name and species epithet. The lower leaf surface is covered with a whitish, waxy bloom (glaucous). The margins are shallowly toothed. Young leaves are hairy, older leaves less so.

What appear to be flowers are actually false flowers (cyathia) common to the Euphorbiaceae (spurge) family. The inflorescence is usually a small, leafy cluster of cyathia, sometimes a single cyathium, rising from a leaf axil.

The cyathium is less than ⅛″ wide. It is on a stalk up to ⅛″ long. There are no petals or sepals. A single floral bract is formed into a hairless, 1 ⁄16″ long cup (involucre). The involucre is split on one side ¼ to ⅓ of its length. There are 4 white, spreading, petal-like lobes at the tip. There are 2 to 5 male flowers and a single female flower in the cyathium. The male flower has 1 stamen. The female flower has a 3-valved, hairy, seed capsule hanging alongside the involucre.

The fruit is a 3-lobed, hairy capsule with 3 seeds.

Prostrate: usually less than 1″ in height

Cream

The three lobed capsule identifies this as a spurge. The prostrate form, the red spot on the leaves, and the hairy stems and seed capsules identify this as spotted spurge.

Nodding spurge (Euphorbia nutans) stems are usually ascending, sometimes erect.

Prostrate knotweed (Polygonum aviculare) is similar in form and appearance. However, it does not emit milky sap from broken stems and leaves. It has a sheath that surrounds the stem above each leaf axil.

Dry. Meadows, open woods, lawns, gardens, sidewalk cracks, and other disturbed sites. Full sun.

May to September

Sources

2, 3, 4, 5, 7, 28, 29, 30.

Native

Common

Spotted spurge was formerly classified as Chamaesyce maculata. Species were originally assigned to the genus Chamaesyce based on the structure of the reproductive organs. Genus wide molecular studies in 2002, 2006, 2007, and 2010 have all unequivocally placed them in the genus Euphorbia, where they were subsequently transferred.

The species epithet maculata is derived from the Latin word maculatus, and means “spotted”. It refers to the reddish spot often near the middle of the leaves of this plant.

Mat

Plant

Leaves

Infructescence

This weed has infested my garden and has been nothing but a headache to manage. I wish it would go away!