The whole of the British species of Spurge have a singular character, which enables the tyro in botanical matters to determine the genus at a glance, though he may not be so successful in distinguishing between the twelve or thirteen native species. This singularity is chiefly due to the colour and arrangement of their flowers. These possess neither sepals nor petals; instead, a number of unisexual flowers are wrapped in an _involucre_. An individual involucre of, say, the Sun Spurge, should be detached and examined with the aid of the pocket-lens. It will be seen to have four lobes, to each of which is attached an orbicular yellow gland. Within the involucre are several flowers, each consisting of a single stamen on a separate flower-stalk (note joint), and from the midst of these arises a single pistillate flower on a long, curved stalk. With slight variations this is the form of inflorescence which characterizes the whole genus. The British species may be briefly enumerated thus:--
I. Sun Spurge (_E. helioscopia_). Annual herb with yellow green obovate leaves, the margin of upper half toothed. Milky juice used as a wart-cure. Waste places, June to October.
II. Broad-leaved Spurge (_E. platyphyllos_). Annual. Leaves broad, lance-shaped, sharp-pointed, toothed above middle. Fruit (capsule) warted. Fields and waste places from York southwards: rare. July to October.
III. Irish Spurge (_E. hiberna_). Perennial. Leaves thin, ovate, not toothed, tip blunt or notched; upper leaves heart-shaped. Glands of involucre purple, kidney-shaped. Hedges and thickets, rare; only in North Devon and South and West of Ireland. Flowers May and June. Juice used by salmon-poachers for poisoning rivers.
IV. Wood Spurge (_E. amygdaloides_). Perennial, stout, red, shrubby. Leaves obovate, thick, tough, reddish, 2 to 3 inches long, hairy beneath, lower on short stalks. Involucral glands half-moon shaped, yellow. Woods and copses, chiefly on clay soils. Flowers March to May.
V. Petty Spurge (_E. peplus_). Annual. Leaves thin, broadly obovate, on short stalks, ¾ inch long. Involucral glands half-moon shaped (_lunate_), with long horns. Waste ground, market-gardens and flower-beds. July to November.