Mercurialis L.

Scientific Description

Family Euphorbiaceae.

Habit and leaf form. Herbs; laticiferous, or non-laticiferous and without coloured juice, or with coloured juice. Plants succulent, or non-succulent. Annual, or perennial; sometimes rhizomatous. Mesophytic, or xerophytic. Leaves minute to large; opposite; ‘herbaceous’, or leathery, or fleshy; petiolate; gland-dotted; simple. Leaf blades entire; pinnately veined. Leaves with stipules. Stipules scaly, or leafy, or spiny, or represented by glands; caducous, or persistent. Leaf blade margins crenate. Leaves without a persistent basal meristem. Leaf anatomy. Urticating hairs present, or absent. Stem anatomy. Nodes tri-lacunar, or unilacunar. Secondary thickening developing from a conventional cambial ring, or anomalous; from a single cambial ring.

Reproductive type, pollination. Fertile flowers functionally male and functionally female. Unisexual flowers present. Plants dioecious (rarely a few male flowers developing on female plants), or monoecious (in some polyploid taxa). Female flowers with staminodes (2 subulate staminodia usually present), or without staminodes. Male flowers without pistillodes. Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. Inflorescences axillary; of modified thyrses, the male racemiform or spiciform, the female capituliform-pedunculate. Flowers bracteate (female bracts 1-flowered, male several-flowered); minute, or small, or medium-sized; regular. Free hypanthium absent. Hypogynous disk absent. Perianth sepaline; 3; 1 -whorled. Calyx 3; polysepalous, or gamosepalous; valvate (in male flowers), or imbricate (in female flowers); regular. Fertile stamens present, or absent (female flowers). Androecium 8–15(–20). Androecial members free of the perianth; free of one another. Androecium exclusively of fertile stamens. Stamens 8–15(–20); polystemonous; variously orientated in bud. Anthers dehiscing transversely; extrorse; bilocular to four locular; bisporangiate, or tetrasporangiate. Fertile gynoecium present, or absent (male flowers). Gynoecium 2(–3) carpelled. The pistil 2(–3) celled. Gynoecium syncarpous; synovarious, or synstylovarious (depending on interpretation of partially connate styles); superior. Ovary plurilocular; 2(–3) locular. Styles 2(–3); partially joined (basally connate); simple; apical. Stigmas 2(–3); dry type; papillate; Group II type. Placentation axile, or apical. Ovules 1 per locule; pendulous; epitropous; with ventral raphe, or with dorsal raphe; arillate; anatropous.

Fruit and seed features. Fruit non-fleshy; dehiscent; a capsule. Seeds endospermic. Endosperm oily. Seeds arillate. Cotyledons 2 (much wider than the radicle). Embryo straight, or curved. Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, biochemistry. Mustard-oils present, or absent.

Geography, cytology, number of species. Adventive.