This section is from the book "An Illustrated Flora Of The Northern United States, Canada And The British Possessions Vol3", by Nathaniel Lord Britton, Addison Brown. Also available from Amazon: An Illustrated Flora of the Northern United States, Canada and the British Possessions. 3 Volume Set..
Erect or climbing shrubs, with opposite mostly entire leaves; flowers spicate, capitate or geminate, usually somewhat irregular. Calyx-tube ovoid or nearly globular, the. limb slightly 5-toothed. Corolla tubular, funnelform, or campanulate, often gibbous at the base, the limb 5-lobed, more or less oblique, or 2-lipped. Stamens 5, inserted on the tube of the corolla; anthers linear or oblong. Ovary 2-3-celled; ovules numerous in each cavity, pendulous; style slender; stigma capitate. Berry fleshy, 2-3-celled or rarely i-celled, few-seeded. Seeds ovoid or oblong with fleshy endosperm and a terete embryo. [Named for Adam Lonitzer, 1528-1586, a German botanist.]
About 160 species, natives of the north temperate zone, a few in tropical regions. Besides the following, some 10 others occur in the western parts of North America. Type species: Lonicera Caprifolium L.
*Climbing or trailing vines; flowers in heads or interrupted spikes; upper leaves connate-perfoliate. Corolla 2-lipped, the upper lip 4-lobed, the lower entire. Corolla glabrous within.
1. L. Caprifolium.
Corolla pubescent within.
Leaves pubescent, at least beneath; corolla yellow.
Leaves pubescent on both sides, at least when young, ciliate; corolla slightly gibbous at base.
2. L. hirsuta.
Leaves glabrous above, pubescent beneath; corolla-tube strongly gibbous at the base.
3. L. glaucescens.
Leaves glabrous on both sides, very glaucous beneath. Corolla greenish-yellow, the tube somewhat gibbous.
Corolla-tube 3"-5" long; filaments hirsute at the base.
4. L. dioica.
Corolla-tube 5"-7" long: filaments nearly glabrous.
5. L. Sullivantii.
Corolla bright yellow or orange, its slender tube not gibbous.
6. L. flava.
Corolla tubular, the short limb nearly equally 5-lobed.
7. L. sempervxrens.
** Climbing vine; flowers in pairs on short axillary peduncles.
8. L. japonica.
*** Shrubs; flowers in pairs on axillary bracted peduncles.
Bracts of the peduncle subulate, linear, minute, or none. Leaves rarely cordate, more or less pubescent, or ciliate.
Leaves pale, or glaucous, thick, strongly reticulate-veined.
Peduncles shorter than the flowers; fruit blue; leaves ciliate.
9. L. coerulea.
Peduncles equalling the Mowers; fruit red; leaves not ciliate.
10. L. oblongifoha.
Leaves bright green, thin, ciliate, not strongly reticulate; fruit red.
11. L. canadensis.
Leaves pale, densely pubescent beneath, even when old.
12. L. Xylosteum.
Leaves cordate, glabrous.
13. L. tatarica.
Bracts of the peduncle broad, foliaceous.
14. L. involucrata.
Climbing high, glabrous and somewhat glaucous. Upper one to three pairs of leaves connate-perfoliate, glaucous beneath, the others sessile or short-peti-oled, oval or obovate, all rounded at the base, entire; flowers in terminal capitate sessile clusters; corolla glabrous within, 1'-1 1/2' long, purple without, the limb white within, strongly 2-lipped; upper lip 4-lobed, the lower one narrow, reflexed; tube slightly curved, not gibbous; stamens and style much exserted; berries red.
Thickets, New York, New Jersey and Pennsylvania to Michigan, Missouri, and in the Southern States. Escaped from cultivation and naturalized. Native of Europe. Called also american or fragrant woodbine. May-June.