Euphorbia maculata

Native

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

May to September

Cream

Usually less than 1″

This 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 red spot near the middle. The lower 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 (cyanthia) common to the Euphorbiaceae (spurge) family. The inflorescence is usually a small, leafy cluster of cyanthia, sometimes a single cyanthium, rising from a leaf axil.

The cyanthum 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 cyanthium. 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.

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.