Ilex L.

Scientific Description

Family Aquifoliaceae.

Habit and leaf form. Small trees, or shrubs; usually evergreen. Stem internodes solid. Leptocaul. Commonly heterophyllous (at least in Ilex aquifolium, which commonly exhibits unarmed leaves on mature shoots, cf. irreversible maturation in Hedera), or not heterophyllous. Leaves alternate, or opposite (rarely), or whorled (rarely in ‘pseudowhorls’); usually spiral; leathery; petiolate; non-sheathing; simple. Leaf blades dissected, or entire; elliptic, or oblong, or obovate; pinnately veined; cross-venulate; attenuate at the base, or rounded at the base. Leaves with stipules (stipules small). Stipules small. Leaf blade margins entire, or dentate. Leaf anatomy. Hairs absent. Extra-floral nectaries absent. Stem anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite, or functionally male, or hermaphrodite, functionally male, and functionally female (? flowers hermaphrodite or unisexual). Unisexual flowers present. Plants dioecious, or polygamomonoecious. The unisexual flowers segregated in different inflorescences. Female flowers with staminodes, or without staminodes (four staminodes, these sometimes petaloid, but not seen in Australian material). Male flowers with pistillodes.

Inflorescence and flower features. Flowers solitary (rarely), or aggregated in ‘inflorescences’; in cymes, or in umbels, or in fascicles (cymose-). The terminal inflorescence unit cymose, or racemose. Inflorescences axillary (or lateral); male cymes several on axillary rachis, female cymes single on axillary peduncle; male flowers in compound umbels, female flowers in axillary umbels. Flowers pedicellate (usually), or sessile; regular; 4(–8) merous. Free hypanthium absent. Hypogynous disk absent. Perianth with distinct calyx and corolla; 0, or 4–5, or 8; 1 -whorled, or 2 -whorled; isomerous, or anisomerous. Calyx present; 6–8 (sometimes 4); 1 -whorled; gamosepalous (connate at the base); blunt-lobed; imbricate. Calyx lobes very broadly ovate, or orbicular (to semicircular). Corolla present; 6–8; 1 -whorled; polypetalous, or gamopetalous (connate only at the base); imbricate; white, or cream. Petals elliptic, or oblong. Corolla lobes elliptic, or oblong. Fertile stamens present, or absent (female flowers). Androecial members definite in number. Androecium 6–8. Androecial members free of the perianth to adnate (usually adnate to the corolla base); free of one another; 1–3 -whorled. Androecium exclusively of fertile stamens, or including staminodes. Staminodes apparently none in Australian material. Stamens 6–8; isomerous with the perianth to triplostemonous; oppositisepalous (epipetalous). Anthers dehiscing via longitudinal slits; introrse; tetrasporangiate. Fertile gynoecium present, or absent. Gynoecium (2–)4–6(–24) carpelled. The pistil (2–)4–6(–24) celled. Gynoecium syncarpous; eu-syncarpous; superior. Ovary plurilocular; (2–)4–6(–24) locular; sessile. Gynoecium non-stylate (usually), or stylate (AK). Styles 1 (or 0); apical. Stigmas 1; capitate. Placentation apical. Ovules 1–2 per locule; pendulous; apotropous; non-arillate; anatropous.

Fruit and seed features. Fruit fleshy; indehiscent; a drupe (with as many pyrenes as locules); 1 seeded (per cell). Seeds endospermic. Endosperm oily (and proteinaceous). Cotyledons 2. Embryo straight.

Geography, cytology, number of species. World distribution: widespread.

Economic uses, etc. Ilex species supply hard, white, fine-grained wood, used for inlay work and sometimes stained black as ebony substitute; Maté or Paraguay tea from dried leaves of I. paraguensis; many species and hybrids used as ornamentals.

Etymology. From the Latin for "holm-oak or evergreen oak", Quercus ilex; the foliage of which resembles holly.