Caprifoliaceae Juss.

Scientific Description

Common name. Honeysuckle Family.

Habit and leaf form. Shrubs, or trees (small), or herbs (rarely), or lianas; evergreen, or deciduous. Self supporting, or climbing; when climbing, stem twiners. Lonicera twining clockwise. Mesophytic. Leaves small to medium-sized; opposite (usually), or whorled; petiolate; connate, or not connate; simple; epulvinate. Leaf blades dorsiventral; dissected (rarely), or entire; when lobed pinnatifid; pinnately veined; cross-venulate. Leaves with stipules, or without stipules; without a persistent basal meristem. Domatia recorded (from two genera); represented by pits, or pockets, or hair tufts. Stem anatomy. Nodes unilacunar (rarely), or tri-lacunar. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Fertile flowers hermaphrodite, or hermaphrodite, functionally male, and functionally female. Unisexual flowers present, or absent. Plants hermaphrodite, or polygamomonoecious. Entomophilous.

Inflorescence and flower features. Flowers aggregated in ‘inflorescences’. The terminal inflorescence unit cymose (basically, but the flowers are commonly in axillary pairs, and in Lonicera the members of each pair are sometimes basally congenitally fused). Inflorescences axillary. Flowers usually bracteolate; often fragrant; regular to very irregular; usually more or less zygomorphic. The floral asymmetry involving the perianth, or involving the perianth and involving the androecium. Flowers 4–5 merous; tetracyclic. Free hypanthium absent. Perianth with distinct calyx and corolla; (6–)8–10; 2 -whorled; isomerous. Calyx present; (2–)4–5; 1 -whorled; gamosepalous (usually), or polysepalous (Weigela); lobed; imbricate, or open in bud; regular; persistent; with the median member posterior. Corolla present; 4, or 5; 1 -whorled; gamopetalous; imbricate; regular, or unequal but not bilabiate, or bilabiate; white, or cream, or yellow, or red, or pink, or purple (or some combination). Fertile stamens present, or absent (from female flowers). Androecial members definite in number. Androecium (2–)4, or 5. Androecial sequence not determinable. Androecial members adnate (epipetalous); all equal to markedly unequal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens. Stamens (2–)4, or 5. Staminal insertion near the base of the corolla tube, or midway down the corolla tube, or in the throat of the corolla tube. Stamens didynamous, or not didynamous, not tetradynamous; isomerous with the perianth; oppositisepalous. Anthers dorsifixed; dehiscing via longitudinal slits; introrse; bilocular; tetrasporangiate. Fertile gynoecium present, or absent (from male flowers). Gynoecium 2–5–8 carpelled. The pistil 2–8 celled. Gynoecium syncarpous; synstylovarious, or eu-syncarpous; inferior. Ovary plurilocular; 2–8 locular. Gynoecium stylate. Styles 1; apical. Stigmas 1; capitate; dry type; papillate; Group III type. Placentation axile to apical. Ovules 1–50 per locule (to ‘many’); pendulous; apotropous; with dorsal raphe; anatropous.

Fruit and seed features. Fruit fleshy, or non-fleshy; dehiscent, or indehiscent; a capsule, or achene-like, or a berry (the fused pairs of flowers of some Lonicera species resulting in compound berries), or a drupe. The drupes with one stone (e.g. Viburnum), or with separable pyrenes (e.g. Symphoricarpos). Capsules valvular (Weigela). Seeds endospermic. Endosperm ruminate, or not ruminate; oily. Cotyledons 2. Embryo achlorophyllous; straight. Seedling. Germination phanerocotylar.

Physiology, biochemistry. Photosynthetic pathway: C₃.

Geography, cytology, number of species. World distribution: Widespread worldwide, but mostly North temperate and tropical mountains — missing from most of Africa. X = 8 or 9(–12). About 450 species.

Economic uses, etc. Cultivated ornamental shrubs and vines from Lonicera, Viburnum, Symphoricarpos, Abelia, Leycesteria, Linnaea, Kolkwitzia; noxious weeds (Lonicera japonica).