A guide to nonnative invasive plants inventoried in the north by ...

Appendix C
Key to the species Lonicera
1. Woody vines...2
1. Shrubs...4
2. Flowers and fruits sessile; all leaves petiolate...Lonicera japonica
2. Flowers and fruits stalked; upper leaves connate...3
3. Corolla strongly bilabiate, less than 2.7 cm long; all leaves
connate...Lonicera dioica
3. Corolla scarcely bilabiate, more than 2.7 cm long; some lower
leaves petiolate...Lonicera sempervirens
4. Flowers and fruits sessile...Lonicera maackii
4. Flowers and fruits stalked...5
5. Flowers appearing before the leaves expand...Lonicera
fragrantissima
5. Flowers appearing after the leaves expand...6
6. Style glabrous...Lonicera canadensis
6. Style hirsute...7
7. Corolla strongly bilabiate...Lonicera xylosteum
7. Corolla scarcely bilabiate...8
8. Leaves glabrous beneath; peduncles 1.5-2.5 cm...Lonicera
tatarica
8. Leaves hairy beneath; peduncles 0.5-1.5 cm...Lonicera morrowii
(Note: Lonicera ×bella, the hybrid between L. tatarica and L.
morrowii, combines characters of both species and is very
difficult to separate from its parents.)
Definitions:
Sessile - attached directly to the base, without a stalk.
Glabrous - smooth, without hairs or glands.
Bilabiate - two-lipped.
Peduncle - stalk of an inflorescence or of a solitary flower.