Northern Ontario Plant Database

Plant Description

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The Genus Lonicera

Caprifoliaceae (Honeysuckle Family)

Plants of the genus Lonicera (honeysuckle) have simple, opposite leaves with entire margins. In the woody vines (L. dioica and L. hirsuta), the upper 1–4 leaf pairs are fused at the base, forming connate-perfoliate leaves. The uppermost pair forms a rounded to oblong, concave, saucer-like disk that subtends the terminal spike of several whorled flowers. In shrubby species, the leaves are not connate and flowers occur in pairs in the leaf axils.

The calyx of honeysuckle flowers is small and inconspicuous. The corolla is funnelform or tubular, with a gibbous bulge near the base of the tube; the 5 rounded lobes comprise less than half the length of the corolla. The 5 corolla lobes are arranged either in a slightly irregular, bilabiate form, with 2 lower lobes and 3 upper lobes, or strongly bilabiate, with 1 lower lobe and 4 upper lobes. Stamens are 5 and attached to the inner surface of the corolla tube (epipetalous). The pistil is composed of a compound, inferior ovary, a long style, and a large, capitate stigma. Glandular hairs in the base of the corolla tube produce nectar.

There is one introduced species, Lonicera tatarica (Tartarian honeysuckle), that we have found to be persistent around old homestead sites. This species can be identified by its glabrous, ovate leaves with rounded to slightly cordate bases, pinkish-white corollas, and its paired globose red berries.

Keys to the native honeysuckles are provided below, followed by comparison charts to the native vine species (Lonicera Chart I) and the native shrub species (Lonicera Chart II).

Keys to the native Lonicera species of northern Ontario

1a.	Woody vines, when young with weak, arching stems; terminal leaf pairs connate-perfoliate; flowers in terminal whorled spikes subtended by a connate disk.		go to 2
1b.	Shrubs; leaf pairs all distinct, none connate at the base; flowers in axillary pairs.		go to 3
	2a.	Leaves hairy on both surfaces, at least somewhat, leaf margins and petioles ciliate, young stems green to purplish, not glaucous.
	Lonicera hirsuta (hairy honeysuckle)
	2b.	Leaves glabrous, bluish white and glaucous beneath, margins entire, not ciliate; young stems glaucous.
	Lonicera dioica (glaucous honeysuckle)
3a.	Mature leaves hairy on both surfaces; flowers borne on short stalks <1 cm long, fruits blue.
Lonicera villosa (northern fly-honeysuckle)
3b.	Mature leaves smooth or hairy on lower surface; flowers on long stalks >1 cm long; fruits red or black.		go to 4
	4a.	Leaves with sharp-pointed tips; flowers subtended by 4 red leafy bracts; berries black.
	Lonicera involucrata (bracted honeysuckle)
	4b.	Leaves with blunt to rounded tips; flowers not subtended by leafy bracts; berries red.	go to 5
5a.	Leaves elliptic to broadly ovate, bases tapering to slightly cordate, margins and petiole ciliate; outer surface of corolla smooth; berries paired, joined only at bases, with tips facing in opposite directions.
Lonicera canadensis (Canada fly-honeysuckle)
5b.	Leaves oblong to obovate, tapering at the base; margins not ciliate; outer surface of corolla hairy; berries paired, joined for at least half their length.
Lonicera oblongifolia (oblongleaf honeysuckle)

Lonicera chart I: Native climbing or trailing vines with terminal whorls of flowers and fruits

trait	Lonicera hirsuta (hairy honeysuckle)	Lonicera dioica (glaucous honeysuckle)
leaf shape	broadly elliptic, oval, or ovate	narrowly elliptic to oblong
leaf surface	somewhat hairy on both surfaces	smooth, usually glaucous beneath
leaf apex	acute to blunt	blunt to rounded
leaf base	rounded or tapering, upper 1–2 leaves connate-perfoliate	tapering, upper 1–4 leaves connate-perfoliate
leaf margins	ciliate	entire
fruit	a cluster of orange to red, ovoid berries, subtended by a connate-perfoliate disk

Lonicera chart II: Native erect shrubs with axillary flowers and fruits

traits	L. oblongifolia (swamp fly honeysuckle)	L. canadensis (Canada fly honeysuckle)	L. villosa (northern fly honeysuckle)	L. involucrata (bracted honeysuckle)
leaf shape	oblong to obovate	elliptic to broadly ovate	elliptic, oblong, or oblanceolate	elliptic to obovate
leaf surface	hairy when young, smooth at maturity		hairy on both surfaces	nearly smooth above, hairy beneath
leaf apex	blunt to rounded			sharply pointed (acuminate)
leaf base	gradually tapering	upper leaf bases narrow and tapering; lower leaf bases somewhat cordate	tapering to rounded
leaf margins	not ciliate	ciliate
corolla	outer surface hairy	outer surface smooth
bracts	no showy bracts			showy red bracts, subtending the fruit
fruit	fused for at least half their length	fused only at the base	a single globose blue berry, formed from a pair of fused ovaries	pairs of distinct, globose purplish-black berries

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