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The families of flowering plants

L. Watson and M.J. Dallwitz

Caprifoliaceae Juss.

Including Diervillaceae (Raf.) Pyck., Linnaeaceae (Raf.) Backlund, Loniceraceae von Vest, Viburnideae (Viburnaceae) Dum. (p.p.); excluding Carlemanniaceae, Dipsacaceae, Morinaceae, Sambucaceae, Valerianaceae, Viburnaceae.

Habit and leaf form. Shrubs, or trees (small), or herbs (rarely), or lianas. Plants green and photosynthesizing. Self supporting, or climbing; when climbing, stem twiners; Lonicera twining clockwise. Mesophytic. Leaves persistent, or deciduous; small to medium-sized; opposite (usually), or whorled; ‘herbaceous’ (mostly), or leathery; petiolate; connate (occasionally), or not connate; simple; epulvinate. Lamina dissected (exemplified in Leycesteria), or entire; when lobed, pinnatifid; pinnately veined; cross-venulate. Leaves stipulate (sometimes large, e.g. Pentapyxis, = Leycesteria), or exstipulate; leaf development not ‘graminaceous’. Domatia occurring in the family (known from two genera); manifested as pits, or pockets, or hair tufts.

General anatomy. Plants without ‘crystal sand’.

Leaf anatomy. The leaf lamina always more or less dorsiventral (usualy with a single palisade layer). Stomata mainly confined to one surface (abaxial); anomocytic. Hairs present; eglandular and glandular (the former usually simple unicellular, the latter with uniseriate stalk and multicellular head in most genera, peltate in Diervilla and Symphoricarpos).

Axial (stem, wood) anatomy. Secretory cavities as distinct from secretory cells with unidentified contents, absent. Cork cambium present; initially superficial. Nodes unilacunar (rarely), or tri-lacunar. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring. Primary medullary rays narrow.

The wood typically ring porous, or semi-ring porous. The vessels very small to small; exclusively solitary. The vessel end-walls scalariform, or simple, or scalariform and simple. The vessels without vestured pits; commonly with spiral thickening (this faint), or without spiral thickening. The axial xylem with tracheids; without vasicentric tracheids; with fibre tracheids (usually), or without fibre tracheids (sometimes in Abelia); without septate fibres. The fibres commonly with spiral thickening. The parenchyma rather sparse, diffuse apotracheal (in most genera), or paratracheal (but very scanty, in Lonicera). ‘Included’ phloem absent. The wood not storied.

Reproductive type, pollination. Plants hermaphrodite, or polygamomonoecious. Pollination entomophilous.

Inflorescence, floral, fruit and seed morphology. Flowers solitary (rarely, Triostem), or aggregated in ‘inflorescences’; if solitary, axillary; in cymes, or in racemes, or in spikes, or in heads, or in verticils. The ultimate inflorescence units cymose (basically, but the flowers are commonly in axillary pairs, and in Lonicera the members of each pair are sometimes basally congenitally fused). Inflorescences terminal, or axillary. Flowers usually bracteolate; often fragrant; nearly always somewhat irregular to very irregular (except in Pentapyxis = Leycesteria p.p. and a few species of Lonicera); nearly always at least slightly zygomorphic. The floral irregularity involving the perianth (often only the corolla), or involving the perianth and involving the androecium. Flowers 4–5 merous; cyclic; tetracyclic. Free hypanthium absent.

Perianth with distinct calyx and corolla; 8–10; 2 whorled; isomerous. Calyx (2–)4, or 5; 1 whorled; gamosepalous (usually), or polysepalous (Weigela); unequal but not bilabiate, or regular; non-fleshy; persistent, or not persistent; non-accrescent; imbricate, or open in bud; with the median member posterior. Corolla 4, or 5; 1 whorled; gamopetalous; imbricate; campanulate, or funnel-shaped, or tubular; unequal but not bilabiate, or bilabiate (very rarely equal); white, or yellow, or red, or pink, or purple (or various combinations).

Androecium (2–)4, or 5. Androecial members adnate (epipetalous); all equal, or markedly unequal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens (2–)4, or 5; inserted near the base of the corolla tube, or midway down the corolla tube, or in the throat of the corolla tube; didynamous, or not didynamous, not tetradynamous; isomerous with the perianth; oppositisepalous. Anthers separate from one another; dorsifixed; dehiscing via longitudinal slits; introrse; bilocular; tetrasporangiate. Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral. Anther wall initially with one middle layer; of the ‘dicot’ type. Tapetum amoeboid, or glandular. Pollen grains aperturate; usually 3 aperturate; colpate, or porate, or colporate (or colporoidate), or zoniaperturate (sometimes zonorate in Abelia); 3-celled.

Gynoecium 2–5–8 carpelled. Carpels reduced in number relative to the perianth, or isomerous with the perianth, or increased in number relative to the perianth. The pistil 2–5(–8) celled. Gynoecium syncarpous; eu-syncarpous; inferior. Ovary 2–8 locular. Epigynous disk present, or absent. Gynoecium stylate (elongate). Styles 1; apical. Stigmas 1; 1–5 lobed; capitate (usually), or truncate; wet type; papillate; Group III type. Placentation axile to apical. Ovules 1–50 per locule (to ‘many’); pendulous; apotropous; with dorsal raphe; often biseriate; non-arillate; anatropous; unitegmic; tenuinucellate. Embryo-sac development Polygonum-type, or Allium-type, or Adoxa-type. Polar nuclei fusing prior to fertilization. Antipodal cells formed; 3; not proliferating; ephemeral. Synergids pear-shaped. Endosperm formation cellular. Embryogeny asterad (and other types?).

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 (e.g. Symphoricarpos, Triosteum). Capsules valvular (Weigela). The drupes with separable pyrenes. Fruit 5–50 seeded (to ‘many’). Seeds endospermic. Endosperm not ruminate; oily. Cotyledons 2. Embryo achlorophyllous (5/16); straight.

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. C3. C3 physiology recorded directly in Lonicera, Symphoricarpos. Anatomy non-C4 type (Symphoricarpos). Cyanogenic, or not cyanogenic. Cynogenic constituents phenylalanine-derived. Alkaloids present, or absent. Arbutin absent. Iridoids detected; ‘Route I’ type (normal and seco). Proanthocyanidins present, or absent; when present, cyanidin. Flavonols present (mostly), or absent (Abelia); kaempferol and quercetin (mostly), or quercetin. Ellagic acid absent (11 species, 7 genera). Aluminium accumulation not found.

Geography, cytology. Temperate, sub-tropical to tropical (at altitude). Widespread, but mostly North temperate and tropical mountains - missing from most of Africa. X = 8 or 9(–12).

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Corniflorae; Dipsacales. Cronquist’s Subclass Asteridae; Dipsacales. APG III core angiosperms; core eudicot; Superorder Asteranae; campanulid. APG IV Order Dipsacales.

Species about 330. Genera 12; Abelia, Diervilla, Dipelta, Heptacodium, Kolkwitzia, Leycesteria, Linnaea, Lonicera, Symphoricarpos, Triosteum, Weigela, Zabelia.

General remarks. Analyses of rbcL sequences by Backlund and Bremer (1997) indicated that Viburnum should be removed from Caprifoliaceae; that it is closely related to Adoxa and Sambucus; and that these three genera (i.e., the tribe Sambuceae of the Bentham and Hooker Caprifoliaceae, 1876) are related to Apiales or Cornales rather than to Dipsacales. Then Backlund and Pyck (1998) proposed Diervillaceae (Diervilla, Weigela and Linnaeaceae (Abelia, Dipelta, Kolkwitzia, Linnaea, Zabelia) as families separated from but closely related to Caprifoliaceae sensu stricto, without bothering to revise the family descriptions. Anyway, comparisons among descriptions in the present package show that while Carlemanniaceae differ conspicuously from Caprifoliaceae only in details of the anroecium and pollen morphlogy, Dipsacaceae, Morinaceae, Sambucaceae, Valerianaceae, and Viburnaceae all differ from Caprifoliaceae sensu stricto, and from one another, in far too many characters to be sensibly reduced to synonymy.

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


Sleep thou, and I will wind thee in my arms,
So doth the woodbine - the sweet honeysuckle -
Gently entwist
(‘Midsummer Night’s Dream’, iv., 1)

Illustrations. • Le Maout and Decaisne: Lonicera, Symphoricarpos. • Linnaea borealis, Lonicera tatarica: Lindley. • Kolkwitzia amabilis: Hook. Ic. Pl. 30 (1911). • Linnaea borealis: B. Ent. 762, 1839. • Lonicera calcarata: Hook. Ic. Pl. 27 (1900). • Lonicera caprifolium: B. Ent. 124, 1826. • Lonicera ciliosa var. occidentalis: as Caprifolium occidentale, Bot. Reg. 1457 (1831). • Lonicera hirsuta: as Caprifolium, Bot. Reg. 1761, 1836. • Lonicera periclymenum: Eng. Bot. 642 (1865). • Lonicera xylosteum: Eng. Bot. 643 (1865). • Lonicera quinquelocularis: as L. diversifolia, Bot. Reg. 1844, 33. • Leycesteria formosa: Bot. Reg. 1839, 2. • Leycesteria sinensis: Hook. Ic. Pl. 27 (1900).

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 5th March 2018.’.