The familial limits of Caprifoliaceae have considerably changed as a result of recent phylogenetic molecular research (APGIII 2009). As currently circumscribed it includes Dipsacaceae and Valerianaceae. On the other hand, Sambucus and Viburnum have been transferred to Adoxaceae. Diervillaceae and Linnaeaceae, sometimes considered as a separate family (here represented respectively by the genera Weigela and Kolkwitzia), are now included in Caprifoliaceae but raised as distinct families by some authors, for instance in Flora of China (Yang & al. 2011, following Backlund & Pyke 1998).
1. Shrubs or vines (if occasionally more or less herbaceous, then with large, often purplish bracts subtending the flowering spikes) === 2
1. Herbaceous annuals, biennials or perennials, never with conspicuous colourful bracts subtending the inflorescence === 6
2. Fruit a dry capsule === 3
2. Fruit a hemispherical berry === 4
3. Ovary 2-celled (each with many ovules), not bristly hairy. Calyx deciduous in fruit. Flowers solitary or in few-flowered cymes. Stamens 5 === Weigela
3. Ovary 3-celled (1 fertile, 2 sterile), bristly hairy. Calyx persistent in fruit. Flowers paired. Stamens 4 === Kolkwitzia
4. Inflorescence an elongated spike, with large, colourful (often purplish) bracts === Leycesteria
4. Inflorescence usually whorled or in pairs, without or with very indistinct bracts === 5
5. Fruit with numerous seeds. Evergreen or deciduous shrubs or vines. Corolla zygomorphic (with 4-lobed upper lip and unlobed lower lip) or actinomorphic (with 5 more or less equal lobes), variously coloured === Lonicera
5. Fruit with two seeds. Deciduous shrubs. Corolla actinomorphic, always whitish or pinkish === Symphoricarpos
6. Stamens 1 or 3 === 7
6. Stamens 4 or 5 === 9
7. A single stamen. Corolla with conspicuous spur at base (2-12 mm long), reddish or more rarely white. Glabrous perennial, often glaucous === Centranthus
7. Three stamens. Corolla without a distinct spur, at most pouched at base, pinkish, whitish or pale lilac. Hairy or more or less glabrous annuals or perennials === 8
8. Annual. Leaves entire, serrate or sparsely lobed. Calyx remaining more or less minute in fruit, never developing into a conspicuous feathery pappus. Stem forked at each node. Corolla not pouched at base === Valerianella
8. Perennial. At least some leaves distinctly lobed. Calyx much enlarging in fruit, developing into a feathery pappus. Stem not forked above. Corolla pouched at base === Valeriana
9. Stem and leaves prickly (sometimes scarcely so). Receptacle scales spine-tipped === Dipsacus
9. Stem and leaves without prickles. Receptacle scales, if present, not spine-tipped === 10
10. Corolla 5-lobed. Involucel (epicalyx) expanded at maturity into a membranous corona with many teeth (native) === 11
10. Corolla 4-lobed. Involucel different === 12
11. Tube of involucel (epicalyx) with 8 longitudinal grooves, these extending over total length of tube === Scabiosa
11. Tube of involucel with 8 apical pits, these up to ½ as long as tube === Lomelosia
12. Receptacle hairy or bristly, without scales subtending each flower === Knautia
12. Receptacle with scales subtending each flower === 13
13. Either tall (up to 350 cm) perennial with creamy corollas and pinnatifid to pinnatisect leaves or smaller annual with lilac-blue corollas and entire or toothed leaves === Cephalaria
13. Perennial with bluish-violet corollas and entire or toothed leaves (native) === Succisa
APG III (2009) An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants. APG III. Bot. J. Linn. Soc. 161(2): 105-121.
Backlund A. & Pyck N. (1998) Diervillaceae and Linnaeaceae, two new families of caprifolioids. Taxon 47: 657-661.
Yang Q., Landrein S., Osborne J. & Borosova R. (2011) Caprifoliaceae. In: Flora of China Editorial Committee (ed.), Flora of China, vol. 19. Science Press, Beijing & Missouri Botanical Garden Press, St. Louis: 616-641.