Northern Ontario Plant Database

Plant Description

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The Genus Vaccinium

Ericaceae (Blueberry Family)

There are 11 species of Vaccinium in Ontario. These can be divided into 5 categories: blueberries, bilberries, deerberries, cranberries, and mountain cranberries.

Plants are mostly woody shrubs of forests or barrens, but some species are creeping dwarf shrubs (cranberries and mountain cranberry). Leaves are alternately arranged, simple, deciduous or evergreen, and sessile or petiolate.

Flowers may be solitary in the leaf axils, or borne in short terminal or axillary racemes; flowers parts are arranged in multiples of 4 or 5. The calyx is short, with 4-5 lobes; The corolla varies in shape between different species of Vaccinium; it will be urn-shaped (urceolate) in blueberries and bilberries, bell-shaped (campanulate) in deerberries and mountain cranberries, and deeply divided into 4 reflexed lobes in cranberries. There are 8–10 stamens, twice the number of the perianth parts; anthers dehisce through a pore at the apex of each locule, which is prolonged into a short to long tube; the stamens may extend beyond the corolla (exserted), or they may be included within the corolla. Some species (bilberries and deerberries) also bear awns at the base of the anthers. The compound ovary is inferior and bears a single, erect style; the fruit is an edible berry (technically a false berry or epigenous berry, derived from an inferior ovary). Berries may be blue, blackish, or red, and contain numerous small seeds.

Of the 11 Ontario Vaccinium species, three are restricted to southern Ontario. One of these, V. stramineum (deerberry) is known only from a few locations in the Niagara River and Thousand Islands areas; it can be distinguished by its open, campanulate flowers. The other two species (V. corymbosum and V. pallidum) are distributed more widely throughout southwestern and eastern Ontario. The key below includes all of the Vaccinium species native to southern Ontario, but the comparison charts deal only with species whose range extends into northern Ontario.

Go to the Vaccinium key for all species native to Ontario. Go to Vaccinium comparison charts for species in northern Ontario only. Go to distribution chart of all Vaccinium species native to Ontario.

Key to the Vaccinium (blueberry, bilberry, cranberry, and deerberry) species of Ontario

1a.	Low, creeping dwarf shrubs with evergreen leaves and red berries.		go to 2
1b.	Erect or spreading shrubs with deciduous leaves and blue to purplish-black berries.		go to 4
	2a.	Leaves elliptic to obovate, to 2.5 cm long; the undersurface paler and bearing scattered, dark glandular bristles; corolla bell-shaped (campanulate) with 4-5 short recurved lobes.
	Vaccinium vitis-idaea (mountain cranberry, partridgeberry)
	2b.	Leaves oblong to triangular, to 1.5 cm long; the undersurface paler but lacking bristles; corolla with 4 deeply cut reflexed lobes (cranberries).	go to 3
3a.	Leaves oblong or oval, with blunt to rounded tips; undersurface paler but not white; flowers originating from the axils of lower leaves, with a pair of greenish, leafy bracts borne above the middle of the fruiting stalk.
Vaccinium macrocarpon (large cranberry)
3b.	Leaves ovate to triangular, with pointed (acute) to blunt tips; undersurface white; flowers terminal at the end of leafy shoots, with a pair of small red bracts borne at or below the middle of the fruiting stalk.
Vaccinium oxycoccus (small cranberry)
	4a.	Flowers with open, bell-shaped (campanulate) corollas; plants restricted to the Niagara River and Thousand Islands areas.
	Vaccinium stramineum (deerberry)
	4b.	Flowers with urn-shaped (urceolate) corollas, somewhat narrowed at the throat of the corolla; plants with a wider range.	go to 5
5a.	Flowers solitary (rarely 2-3) in leaf axils (bilberries).		go to 6
5b.	Flowers several in terminal racemes at ends of lateral branches (blueberries).		go to 8
	6a.	Shrubs 8–12 dm tall, leaves oval to nearly orbicular.
	Vaccinium ovalifolium (oval-leaf bilberry)
	6b.	Shrubs to 6 dm tall, leaves elliptic to oblanceolate.	go to 7
7a.	Leaf margins finely serrate, flower parts in multiples of 5.
Vaccinium caespitosum (dwarf bilberry)
7b.	Leaf margins entire, slightly revolute, flower parts in 4 (less often 5).
Vaccinium uliginosum (alpine bilberry)
	8a.	Plants tall, 1–4 m high; mature leaves 4-8 cm long.
	Vaccinium corymbosum (highbush blueberry)
	8b.	Plants low, less than 1 m high, mature leaves 0.5-4 cm long.	go to 9
9a.	Leaves and stems velvety-hairy.
Vaccinium myrtilloides (velvetleaf blueberry)
9b.	Leaves and stems smooth (glabrous) or nearly so; never velvety at maturity.		go to 10
	10a.	Leaves glabrous, leaf margins finely serrate (serrulate), with tightly spaced teeth; occurring in dry to wet habitats, widespread throughout Ontario.
	Vaccinium angustifolium (lowbush blueberry, early sweet blueberry)
	10b.	Leaves hairy when young, becoming smooth (glabrate), leaf margins serrulate, with widely spaced teeth, to entire, often ciliate; restricted to dry sandy habitats in southern Ontario.
	Vaccinium pallidum (early lowbush blueberry)

Comparison Chart I: Vaccinium Subgenera in northern Ontario

	blueberries (subgenus Cyanococcus)	bilberries (subgenus Euvaccinium)	cranberries (subgenus Oxycoccoides)	mountain cranberries (subgenus Vitis-idaea)
flower # and arrangement	several, in terminal or lateral racemes	solitary (rarely in clusters of 2–3), borne in leaf axils	1-4, terminal or lateral, each on a long pedicel	few, in terminal clusters, each on a short pedicel
corolla	flowers 5-merous, corolla white to pinkish, urn-shaped (urceolate)	flowers 5-merous (4- or 5-merous in V. uliginosum), corolla white, pinkish, or red, urceolate	flowers 4-merous; corolla pink, deeply cut into 4 reflexed lobes.	flowers 4- merous; corolla pinkish to red, campanulate, lobes small, slightly recurved.
anthers	10, awnless, included within the corolla	10, awned, included within the corolla	8, awnless, exserted	8, awnless, included within the corolla
berries	blue to blackish, often with a glaucous bloom		red
leaves	deciduous		evergreen; lower leaf surface glabrous	evergreen; lower leaf surface bearing scattered black gland-tipped hairs
species	V. angustifolium V. myrtilloides Go to Chart II	V. ovalifolium V. cespitosum V. uliginosum Go to Chart II	V. macrocarpon V. oxycoccus Go to Chart III	V. vitis-idaea Go to Chart III

Comparison Chart II: northern Ontario blue-berried Vaccinium Species

	plant	stamens	leaves
Flowers several, borne in terminal or lateral racemes.
V. angustifolium (low sweet blueberry, lowbush blueberry)	low shrubs, <1 to 4 dm tall	anthers awnless, with apical tubes about equal to or longer than the pollen sacs	glabrous or nearly so, lower leaf surfaces glabrous to sometimes glaucous, leaf blades lanceolate to elliptic, 0.5-4 cm long, apex pointed (acute to acuminate), margins serrulate, with bristle-tipped teeth
V. myrtilloides (velvetleaf blueberry)	low shrubs, 2-6 dm tall		lower leaf surface and young stems velvety-hairy, leaf blades lanceolate to elliptic, 2-4 cm long, apex pointed (acute to acuminate), margins serrulate, teeth lacking bristle tips
Flowers solitary or in small clusters, borne in leaf axils.
V. ovalifolium (ovalleaf bilberry)	low to medium shrubs, to 6 dm tall; young stems 4-angled	anthers with apical tubes and awns shorter than the pollen sacs	glabrous; leaf blades elliptic, ovate, oval, to nearly orbicular, 1.5–5 cm long; thin-textured (membranaceous), dull above, paler beneath, apex blunt to rounded, margins entire to barely toothed near the base
V. cespitosum (dwarf bilberry)	dwarf shrubs, to 3 dm tall	anthers with apical tubes and awns nearly as long as the pollen sacs	glabrous; leaf blades oblanceolate to obovate, 1-3 cm long, membranaceous, apex acute to rounded, margins serrulate
V. uliginosum (alpine bilberry, bog bilberry)	low shrubs, to 6 dm tall (shorter in the far north)	anthers with apical tubes and awns longer than the pollen sacs	glabrous; leaves elliptic, oblanceolate, to obovate, to 2 cm long, thick (coriaceous), dull above, lower surface paler, with obvious reticulate veins, apex blunt to rounded, margins entire

Comparison Chart III: northern Ontario red-berried Vaccinium Species

	flowers	stamens	leaves
Corolla pink, deeply divided into 4 reflexed lobes
V. macrocarpon (large cranberry)	flowers 1-6, solitary, borne in the axils of lower reduced leaves, each on a 1-3 cm long pedicel that bears a pair of bracts well above the middle	stamens exserted, anthers with apical tubes longer than the pollen sacs	leaves 6-17 mm long and 2-8 mm wide, oval to oblong, apex and base blunt to rounded, margins entire, flat to slightly revolute, lower surface pale, not strongly whitened
V. oxycoccus (small cranberry)	flowers 1-4, solitary, appearing terminal, borne in the axils of uppermost leaves, each on a 1-4 cm long pedicel that bears a pair of bracts near or below the middle		leaves 3-8 mm long and 1-3 mm wide, ovate-elliptic to triangular, apex pointed (acute), base rounded, margins usually strongly revolute, lower surface strongly whitened
Corolla pinkish to red, campanulate, with 4 short, reflexed lobes
V. vitis-idaea (mountain cranberry)	flowers few, in terminal clusters, each on a very short pedicel	stamens included, anthers with apical tubes shorter than the pollen sacs	leaves 5-18 mm long, 4-9 mm wide, oblanceolate to obovate, coriaceous, glossy above, apex rounded, base cuneate, margins entire, slightly revolute, lower surface paler, bearing scattered black gland-tipped hairs

Distribution of Vaccinium species native to Ontario

Vaccinium Species [arranged northernmost to southernmost]	Region of Ontario
	Western	Northern [north of Lake Superior]	North-Central [Algoma to Nipissing]	Ottawa and Southeast	South-Central and Southwest
V. vitis-idaea (mountain cranberry)	yes	yes	no	no	no
V. uliginosum (alpine bilberry)	[absent in far west]	yes	[N of Wawa]	no	no
V. cespitosum (dwarf bilberry)	[absent in far west]	yes	[Algoma]	no	no
V. ovalifolium (ovalleaf bilberry)	no	no	[Algoma and eastern Superior]	no	no
V. macrocarpon (large cranberry)	yes	[to 49� N]	yes	yes	yes
V. oxycoccus (small cranberry)	yes	yes	yes	yes	yes
V. angustifolium (lowbush blueberry)	yes	yes	yes	yes	yes
V. myrtilloides (velvetleaf blueberry)	yes	yes	yes	yes	yes
V. corymbosum (highbush blueberry)	no	no	no	yes	[southwest]
V. pallidum (dryland blueberry)	no	no	no	[St. Lawrence River region]	[from Toronto south]
V. stramineum (deerberry)	no	no	no	[Thousand Islands region]	[Niagara River region]

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