Caprifolium Miller; Euchylia Dulac; Xylosteon Miller.

Shrubs erect or dwarf, rarely small trees, sometimes climbers, deciduous or evergreen. Branches hollow or solid with white or brown pith; winter buds with 1 to several pairs of scales, rounded or acutely 4-angular, inner scales sometimes accrescent and reflexed. Accessory buds sometimes present, occasionally terminal buds reduced and substituted by 2 lateral buds. Leaves opposite, rarely whorled, margin entire, rarely dentate or divided; leaves usually estipulate, occasionally with interpetiolar stipules or a swollen interpetiolar line; sometimes 1 or 2 pairs of leaves below inflorescence connate and forming involucral bracts. Inflorescence thyrsoid, terminal or axillary, cymes opposite and usually reduced to paired flowers, rarely 1-, sometimes 3-flowered. Inflorescence occasionally pedunculate; cymes sessile, sometimes forming a capitulum, or cymes pedunculate with a pair of bracts and 2 pairs of bracteoles; bracts usually small, sometimes leaflike; bracteoles usually free, sometimes ± fused and cupular occasionally enclosing ovaries, sometimes absent. Paired flowers with free or partially to completely fused ovaries. Calyx 5-lobed, rarely 4-lobed, sometimes truncate, base occasionally with a collarlike emergence. Corolla white, yellow, reddish, or purple-red, often changing color after anthesis, campanulate, funnelform, regularly or subregularly 5(or 4)-lobed, or bilabiate and upper lip 4-lobed; tube long or short, often shallowly to deeply gibbous on ventral side toward base, rarely spurred. Nectary of compact sessile glandular hairs on ventral side toward base of corolla tube, occasionally in 5 regular lines, rarely swollen at base of style. Stamens 5; anthers dorsifixed. Ovary 2 or 3(-5)-locular; style slender, hairy or glabrous; stigmas capitate. Fruit a berry, red, blue-black, black, green, or white sometimes pruinose, bracteoles occasionally accrescent in fruit and enclosing paired berries. Seeds 1 to numerous, smooth, pitted or granular, with rounded embryo.

About 180 species: N Africa, Asia, Europe, North America; 57 species (23 endemic) in China.

See Rehder, Rep. (Annual) Missouri Bot. Gard. 14: 27-232, t. 1-20. 1903.

The identities of Lonicera confusa var. glabrocalyx Miau & X. J. Liu (Acta Sci. Nat. Univ. Sunyatseni 28(4): 78. 1989), L. fengkaiensis Miau & X. J. Liu (Acta Sci. Nat. Univ. Sunyatseni 28(4): 78. 1989), L. stenantha Pojarkova var. angustifolia C. Y. Yang & J. H. Fan (J. Aug. 1st Agric. Coll. 18(2): 7. 1995), and L. subrotundata C. Y. Yang & J. H. Fan (J. Aug. 1st Agric. Coll. 18(2): 8. 1995) cannot be determined because of the unavailability of the type specimens for examination or the original publications. One North American species, L. sempervirens Linnaeus, is occasionally cultivated.

Species Complexes

6-8. Lonicera tangutica species complex

Shrubs, deciduous, to 1-4 m tall. Branches with solid pith. Winter buds with 2-4 pairs of scales. Petiole 1-5 mm; leaf blade obovate to lanceolate, 0.5-8.5 × 0.2-2.5 cm, both sur­faces glabrous or pubescent, base cuneate, apex obtuse to acute. Inflorescences axillary, paired flowers; peduncle usually nod­ding, 0-3 cm, slender, glabrous, rarely pubescent; bracts nar­row, sometimes leaflike, usually exceeding or rarely shorter than ovaries; bracteoles sometimes present, separate or fused, minute to 1/4 as long as ovaries, often ciliate. Neighboring 2 ovaries fused completely or at least to middle, elliptic or ob­long, ca. 2 mm, glabrous or occasionally pubescent. Calyx cu­pular, to 2 mm, truncate or with ovate to triangular lobes, gla­brous to pubescent, sometimes ciliate. Corolla white, yellow, or pink, sometimes tinged purple, tubular-funnelform, 8-13 mm; tube glabrous, occasionally with sparse stiff hairs, nectary swol­len or gibbous on ventral side at base of corolla tube, sometimes forming a spur shorter than ovaries; lobes suberect, orbicular-ovate, 1-2 mm; mouth glabrous or with sparse spreading stiff hairs. Stamens inserted at middle of corolla tube; anthers par­tially exserted, glabrous or ciliate. Style exserted by 1-3 mm. Berries orange, red, purple, or black, 5-6 mm in diam.; seeds brownish, ovoid or oblong, 2-2.5 mm, smooth. Fl. May-Aug, fr. Jul-Sep.

Forests, forest margins, grasslands, scrub, mountains; 800-4500 m. Anhui, Gansu, Guizhou, Hebei, Henan, W Hubei, W Hunan, Ning­xia, E Qinghai, Shaanxi, Shanxi, Sichuan, Taiwan, Xizang, NW Yunnan [Bhutan, India (Sikkim), Nepal]. This is a highly variable species complex; further studies are needed for a satisfactory taxonomic treatment.

19-23. Lonicera hispida species complex

Shrubs, deciduous, to 3 m tall, occasionally dwarf. Winter buds with a pair of narrow keeled outer scales, covering inner scales and sometimes longitudinally sulcate. Young branches often pruinose, minutely scabrid to stiffly hairy and glandular hairy, very rarely glabrous. Petiole 1.5-6 mm; leaf blade usually ovate to oblong, sometimes elliptic, 0.6-9 × 0.4-3.5 cm, sub­glabrous, with short stiff hairs or adpressed villous, base cune­ate to slightly cordate, margin hirsute-ciliate, apex acute to ob­tuse and mucronulate. Inflorescences axillary paired flowers, and at base of new shoots; peduncle stout, sometimes slightly compressed, 0.5-2 cm; bracts broadly ovate, 1-4 cm; bracteoles absent. Paired ovaries free, glabrous to hirsute, often glandular hairy. Calyx cupular, 1-4 mm, to 5 mm at fruiting, truncate or lobed; lobes broad and hirsute-ciliate. Corolla yellow-green or dark purple, funnelform, subregular, 13-35 mm; tube shallowly to deeply gibbous toward base, glabrous to puberulent outside and inside at upper part; lobes erect, ovate, 5-10 mm. Stamens and style usually subequaling or longer than corolla, occa­sionally shorter. Style stiffly hairy on lower half. Berries red, black-brown, or blue-black and pruinose, ovoid, 1-1.5 cm, 3-8-seeded; seeds deep brown, irregularly triangular-oblong, 4-5 mm, smooth. Fl. May-Jul, fr. Jul-Sep. 2n = 18*.

Forests, scrub, alpine grasslands, rocky places, slopes, high moun­tains; 1700-4800 m. Gansu, Hebei, ?Henan, Ningxia, Qinghai, Shaanxi, Shanxi, Sichuan, Xinjiang, Xizang, Yunnan [Afghanistan, Bhutan, India (Sikkim), Kashmir, Kazakhstan, Kyrgyzstan, Mongolia, Nepal, Paki­stan; SW Asia (Iran)]. Lonicera sublabiata P. S. Hsu & H. J. Wang (Acta Phytotax. Sin. 17(4): 78. 1979), based on a type specimen collected in Lixian, Sichuan, by Z. He (12715) and kept in the Shanghai Museum of Natural History (SHM), could not be located; it has a short hispid style, a bilabiate corolla (though the 5 lobes are all located on the same side so it must be the result of a deliberate split of the corolla), and it seems to flower with the emerging leaves. Nevertheless, it does not seem to differ signifi­cantly from L. hispida species complex.

27-28. Lonicera alpigena species complex

Shrubs, deciduous, to 4 m tall. Winter buds with 2-5 pairs of outer scales; inner scales accrescent, enlarged and sometimes reflexed. Branches glabrous to densely hairy with mixed glan­dular hairs. Petiole 3-20 mm; leaf blade obovate or ovate-ellip­tic to ovate-lanceolate, 1.5-17 × 0.8-6 cm, with dense or sparse stiff hairs and sparse glands or glabrous, base cuneate to sub­cordate, margin ciliate, apex apiculate to long acuminate. Inflo­rescences axillary, paired flowers; peduncle 0.5-9 cm, usually thickened toward apex; bracts linear-subulate, to 10 mm, or sometimes minute or leaflike and ovate-lanceolate, to 15 mm; bracteoles separate or sometimes fused into a cupule, ovate to oblong, to 1 mm, ciliate. Neighboring 2 ovaries free to fused, glabrous or densely glandular hairy. Calyx lobes ovate to orbic­ular, to 1 mm, sometimes forming a collarlike emergence at base, apex irregularly lobed, sometimes glandular ciliate. Co­rolla bilabiate, purple-red, very rarely white or turning from white to yellow, 1-1.5 cm, outside sparsely pubescent and glan­dular hairy or glabrous; tube 4-7 mm, inside puberulent, deeply gibbous above slender base; upper lip erect, 4-lobed to 1/4; lower lip recurved. Stamens subequaling corolla; filaments and style hirsute on lower part or glabrous. Berries red or black, glo­bose, ca. 1 cm in diam.; seeds ellipsoid, 5-6 mm, shallowly pitted to smooth. Fl. Apr-Jun, fr. Jun-Oct.

Needle-leaved and broad-leaved mixed forests, scrub, grassy slopes; 900-4000 m. Anhui, S Gansu, W Henan, Hubei, Jiangxi, S Ningxia, E Qinghai, S Shaanxi, Shanxi, Sichuan, Xinjiang, Xizang, NW Yunnan, Zhejiang [Afghanistan, Bhutan, India, Kashmir, ?Myanmar, Russia; Europe]. Lonicera alpigena Linnaeus occurs in Europe; further studies are necessary to better understand the relationships within this species com­plex in Europe and Asia. The type specimen of Lonicera jilongensis P. S. Hsu & H. J. Wang (Acta Phytotax. Sin. 17(4): 76. 1979) has suffered extensive insect dam­age, but it seems to belong here.

31-33. Lonicera nigra species complex

Shrubs, deciduous, to 4 m tall. Winter buds with several pairs of outer acute, keeled scales; inner scales sometimes accrescent and enlarged. Branches with white or sometimes brown pith. Young branches and peduncles often puberulent and glandular hairy. Petiole 2-10 mm; leaf blade oblong to elliptic-lanceolate, 1.5-10 × 1-3 cm, glabrous throughout but abaxially often white hairy on midvein, base cuneate to rounded, apex acute to acuminate. Inflorescences axillary, paired flowers; peduncle 0.5-3 cm; bracts lanceolate-linear, ca. 2 mm; bracte­oles free, fused into 2 pairs or into an entire or lobed cupule, 1/3 to almost as long as ovaries, glandular ciliate. Neighboring 2 ovaries free, fused in lower half or completely fused. Calyx lobes triangular or linear-lanceolate, 1-2 mm, sometimes with a collar emergence at base, glandular ciliate. Corolla bilabiate, purplish, purple-red, or white becoming yellow, 9-13 mm; tube ca. 5 mm, shallowly gibbous at base, outside puberulent or gla­brous, inside puberulent; upper lip crenulate; lower lip reflexed. Stamens and style exserted from corolla tube; filaments gla­brous or hairy at base. Style hairy below middle part or throughout. Berries black, often pruinose, globose, 5-7 mm in diam.; seeds oblong or ovoid, 3-7 mm, granular-raised and coarse. Fl. Apr-Jul, fr. Aug-Oct. 2n = 18.

Forests, scrub, coniferous forests, forest margins, grasslands; 1500-4000 m. W Anhui, Gansu, NE Guizhou, W Henan, W Hubei, Jilin, Ningxia, Qinghai, Shaanxi, S Shanxi, Sichuan, Xizang, Yunnan [Bhutan, India, Korea, Nepal; Europe]. Lonicera govaniana Wallich ex Candolle (Prodr. 4: 337. 1830) and L. orientalis Lamarck (Encycl. 1: 731. 1785) belong to L. caucasica Pal­las (Fl. Ross. 1(1): 57. 1784). Further studies are necessary to determine if L. caucasica, predominantly from Asia Minor and S Asia, differs from L. nigra in Europe and China.

34-36. Lonicera maximowiczii species complex

Shrubs, deciduous, to 2 m tall. Winter buds with several pairs of outer acute, keeled scales; inner scales sometimes ac­crescent and enlarged. Branches sparsely puberulent to glabres­cent. Petiole 2-8 mm; leaf blade ovate or broadly ovate to ob­long-lanceolate, 4-12 × 1.5-3.5 cm, abaxially sparsely strigose, minutely tomentose, or glabrous, adaxially sparsely strigose or glabrous, base cuneate to rounded, margin often ciliate, apex acute to acuminate. Inflorescences axillary, paired flowers; pe­duncle 1-2.5 cm, glabrous or sparsely hairy; bracts subulate, 1-3 mm; bracteoles fused into a cupule, 1/3 to as long as ovaries. Neighboring 2 ovaries more than half to completely fused, very rarely completely free. Calyx lobes triangular to linear, 1-1.5 mm. Corolla bilabiate, dark purple to purple-red or white be­coming yellow, ca. 1 cm, outside glabrous; tube slightly gib­bous toward base, ca. 4 mm, inside densely hairy; upper lip 4 lobed, lobes 1-2 mm; lower lip recurved. Stamens and style exserted from corolla tube; filaments hairy at base. Style hairy throughout. Berries red, ovoid-orbicular; seeds yellowish brown, oblong, 4-5 mm, granular and coarse. Fl. May-Jul, fr. Aug-Sep.

Forests, forest margins, scrub; 400-2400 m. S Gansu, Hebei, Hei­longjiang, ?Henan, Jilin, Liaoning, ?Nei Mongol, Ningxia, Shaanxi, Shandong, N Sichuan [Japan, Korea, Russia].

47-51. Lonicera macrantha species complex

Climbers, semievergreen to deciduous. Branches solid, often becoming hollow. Branches, petioles, and peduncles with ± dense spreading, yellow-brown long stiff hairs and minute glandular hairs, grayish pubescent, yellow-brown velutinous, or sometimes glabrous. Petiole 3-15 mm; leaf blade ovate or ob­long to lanceolate, 2-14 × 1-5 cm, abaxially hirsute mixed with short glandular hairs, pubescent, shortly white velutinous, glau­cous with large sessile orange glands, or occasionally subgla­brous, veins reticulate and raised, adaxially hirsute-hairy on veins and midvein, veins conspicuously impressed, sometimes wrinkled, base rounded to subcordate, occasionally broadly cu­neate, margin ciliate and revolute, apex acute to acuminate, sometimes obtuse and mucronate. Flowers fragrant, paired and in racemes toward apex of branchlets, often paniculate with leaflike to subulate involucral bracts; peduncle 1-15 mm, some­times to 40 mm in lower part of inflorescence; peduncle, bracts, bracteoles, and calyx lobes stiffly hairy and glandular hairy; bracts lanceolate to linear, 2-7 mm, occasionally leaflike to 14 mm; bracteoles orbicular-ovate, ca. 1 mm. Neighboring 2 ovaries free, ca. 2 mm, glabrous or sometimes sparsely to densely hirsute or with sessile glands. Calyx lobes lanceolate, 1-2 mm, ciliate. Corolla bilabiate, white, later yellow, (1.5-)3-7 cm, outside with spreading hairs and minute glandular hairs, glabrous, or strigose; tube (1-)2-5 cm, inside densely puberu­lent, not gibbous at base; upper lip 4-lobed, lobes ca. 5 mm; lower lip recurved. Stamens and style slightly exceeding co­rolla, glabrous or sometimes pubescent at base. Berries white or black, sometimes pruinose, 1 of paired ovaries sometimes aborting, globose or ellipsoid, 7-12 mm; seeds few, ovoid, compressed, 5-7 mm, shallowly pitted and furrowed. Fl. Mar-Jul, fr. Jul-Dec.

Forests of mountain valleys or slopes, scrub, riversides, stream­sides, roadsides; 200-2900 m. S Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hainan, Hubei, Hunan, Jiangxi, Shaanxi, Shanxi, Si­chuan, Taiwan, Xizang, Yunnan, Zhejiang [Bhutan, India, Japan, ?Kash­mir, Myanmar, Nepal, N Vietnam]. These species have long been used medicinally in China.