Blueberries and cranberries are one of the most recent fruits to be domesticated and cultivated, although fruit from wild plants has long been harvested by native peoples and settlers. While wild stands of lowbush blueberries are sometimes harvested, cultivars derived from V. corymbosum are the favored commercial source in Michigan. The common name “huckleberry” is widely applied to various blueberries, but that name should be reserved for the true huckleberry (Gaylussacia), with the seeds enclosed in hard stony pits.
1. Stems creeping, prostrate, or trailing, ± lax; leaves evergreen, all or mostly less than 8 mm wide; flowers 4-merous; mature fruit a red berry.
2. Flowers (and fruit) ± crowded, distinctly longer than their stalks; corolla cleft about halfway, ± bell-shaped, with ascending or spreading lobes; leaf blades light green beneath with scattered minute dark elongate glandular projections.
2. Flowers (and fruit) distinctly shorter than their very slender elongate stalks; corolla cleft to the base, the lobes (petals) strongly reflexed; leaf blades whitened beneath, smooth and glabrous.
3. Leaves mostly obtuse or rounded (or even minutely notched) in outline at apex; bracts on pedicels green (rarely red), (0.7–) 0.8–2.7 (–3) mm broad.
3. Leaves mostly acute in outline at the apex; bracts on pedicels red, less than 0.8 (–1) mm broad.
1. Stems ± erect, stiffly bushy; leaves deciduous, of various width; flowers 5-merous [reported 4-merous in V. uliginosum]; mature fruit a blue to black berry (may be reddish when immature).
4. Flowers and fruit 1 (–2) in axils of leaves (or axillary buds); calyx lobes rounded or virtually absent, deciduous, leaving at most a ring on summit of the fruit; anthers with a pair of conspicuous awns or horns laterally; twigs smooth or wrinkled; restricted to Upper Peninsula.
5. Leaves all less than 1.5 cm broad (usually ± 1 cm); plant not over 5 dm tall; new branchlets essentially terete (or obscurely angled); pedicels 1–5 (–7) mm long; berries less than 10 mm in diameter.
6. Leaf blades toothed, membranous, bright green; flowers solitary in axils of foliage leaves, on current year’s growth; bud scales 2.
6. Leaf blades entire, leathery, blue-green; flowers 1–2 from buds on previous year’s stem; bud scales more than 2.
5. Leaves (at least the larger ones) over 1.5 cm broad; plant over 5 dm tall; new branchlets ± sharply ridged, angled, or 2-edged; pedicels (3–) 4–12 mm long; berries (8–) 10–18 mm in diameter.
7. Leaf blades toothed their whole length, clearly acute; mature fruit purple-black.
7. Leaf blades entire (or obscurely toothed on lower half), nearly obtuse to rounded at apex; mature fruit blue-glaucous.
4. Flowers and fruit in terminal or lateral racemes or crowded clusters; calyx lobes acute (to obtuse), persistent as a small toothed crown on the fruit; anthers without horns; twigs warty or wrinkled.
8. Plants ca. 1 m tall or higher, not rhizomatous (but often in alder-like clumps); fully mature leaf blades all or mostly (3.5–) 4–5.5 (–7) cm long; corollas (6–) 6.5–8.5 (–9.5) mm long.
8. Plants less than 1 m tall (usually 0.5 m or less), rhizomatous (usually forming large colonies); fully mature leaf blades (1.2–) 1.5–3.5 (rarely 4) cm long; corollas (4–) 4.5–6 (–6.5) mm long.
9. Leaves beneath and young twigs ± pubescent; margins of leaves entire.
9. Leaves and twigs glabrous or nearly so (pubescence, if any, on margins and main veins, very rarely scattered across undersides of leaves, and in lines on twigs); margins of leaves finely serrate or sometimes (in V. pallidum) entire.
10. Leaf blades finely but regularly and closely serrulate with bristle-tipped teeth their whole length, narrowly elliptic, mostly 2–3 times as long as broad, pale or green beneath.
10. Leaf blades entire or at least partly or irregularly serrate (both conditions sometimes on the same plant), broadly elliptic, mostly about twice as long as broad or shorter, pale beneath.