1 Plant an herb, subshrub, or sprawling shrub, not clonal by underground rhizomes (except Gaultheria procumbens and Epigaea repens), rarely > 3 dm tall; plants mycotrophic or hemi-mycotrophic (except Epigaea, Gaultheria, and Arctostaphylos).

..2 Plants without chlorophyll (fully mycotrophic); stems fleshy; leaves represented by bract-like scales, white or variously colored, but not green; pollen grains single; [subfamily Monotropoideae; tribe Monotropeae].

....3 Petals united; fruit nodding, a berry; flower and fruit several per stem

....3 Petals separate; fruit erect, a capsule; flower and fruit 1-several per stem.

......4 Flowers few to many, racemose; stem pubescent, at least in the inflorescence; plant yellow, orange, or red when fresh, aging or drying dark brown

......4 Flower solitary; stem glabrous; plant white (rarely pink) when fresh, aging or drying black

..2 Plants with chlorophyll (hemi-mycotrophic or autotrophic); stems woody; leaves present and well-developed, green; pollen grains in tetrads (single in Orthilia).

........5 Herb with a rosette of ascending basal leaves; flowers scapose; [subfamily Monotropoideae; tribe Pyroleae].

..........6 Style and filaments straight; filaments straight, the anthers closely surrounding the style; inflorescence distinctly secund (1-sided)

..........6 Style and filaments strongly declined; filaments curved, the anthers not closely surrounding the style; inflorescence slightly or not at all secund (1-sided)

........5 Subshrub or sprawling shrub with cauline leaves; flowers axillary (except scapose in Chimaphila).

............ 7 Plant erect, the leaves clustered near the apex of the single stem.

............ ..8 Leaves lanceolate or oblanceolate, normally 2-4× as long as wide (sometimes proportionately less narrow in stunted individuals; fruit a capsule, borne 1-several on an erect scape above the leaves [subfamily Monotropoideae; tribe Pyroleae]

............ 7 Plant creeping or sprawling, leaves scattered along the stems.

............ ....9 Flowers solitary and axillary; fruit a white berry; [subfamily Vaccinioideae; tribe Gaultherieae]

............ ....9 Flowers in axillary or terminal spikes or racemes; fruit a fleshy loculicidal capsule or red drupe.

............ ......10 Leaves glabrous, 1-3 cm long, tapered to the base; corolla urceolate; calyx not subtended by large bracts; [subfamily Arbutoideae]

............ ......10 Leaves pilose (glabrate in age), 2-10 cm long, rounded or subcordate at the base; corolla salverform, the lobes spreading; calyx subtended by 2 large bracts; [subfamily Ericoideae; tribe Phyllodoceae]

1 Plant either a shrub or tree (> 3 dm tall), or a shrub 1-3 dm tall (rarely a woody needle-leaved subshrub 0.5-1 m and definitely and obviously clonal by underground rhizomes; plants not mycotrophic or hemi-mycotrophic.

............ ........11 Leaves ca. 1 mm wide, 3-12 mm long, appearing opposite, alternate, or whorled (the internodes very short, thus the leaves generally appearing whorled); petals absent; fruit a subglobose, 2-stoned drupe, 1-3 mm in diameter; branches often appearing in whorls of 3-7; [subfamily Ericoideae; tribe Empetreae]

............ ..........12 Leaves 5-15 mm long; shrubs 5-25 dm tall; drupes red, 1.5-3 mm in diameter; [of SC southward]

............ ..........12 Leaves 3-6 mm long; shrubs 1.5-6 dm tall; drupes gray, 1-1.5 mm in diameter; [of NJ northward]

............ ........11 Leaves either > 2 mm wide or < 5 mm long, mostly alternate or whorled; petals present; fruit not as above, mostly either a capsule or 10- or many-seeded berry; branches appearing alternate or whorled; [subfamily Vaccinioideae; tribe Vaccinieae].

............ ............ 13 Ovary inferior; fruit indehiscent, a fleshy berry; [blueberries and huckleberries].

............ ............ ..14 Ovary 10 locular; seeds 10; leaves glandular-punctate, at least on the lower surface (except G. brachycera)

............ ............ ..14 Ovary 4-5 locular; seeds numerous; leaves not glandular-punctate

............ ............ 13 Ovary superior; fruit dehiscent, a dry capsule; [other heaths].

............ ............ ....15 Petals separate; fruit 2-7-locular; either a shrub to 1 m tall with ovate to oblong, evergreen leaves, 0.6-1.2 cm long, or a shrub to small tree 2-6 (-9) m tall with elliptic, deciduous leaves, 4-12 cm long, or a shrub 1-2.5 m tall, with elliptic to ovate, evergreen leaves 2-4 cm long; [subfamily Ericoideae; tribe Phyllodoceae]. {add Rhododendron groenlandicum}

............ ............ ......16 Fruit 2-3 (5)-locular; shrub to 1 m tall; leaves, 0.4-1.2 cm long; petals 2-4 mm long

............ ............ ......16 Fruit 4-7-locular; shrub to small tree 1-6 (-9) m tall; leaves 2-12 cm long; petals 12-30 mm long.

............ ............ ........17 Fruit 7-locular; leaves evergreen 2-4 cm long; petals 20-30 mm long; shrub 1-2.5 m tall

............ ............ ........17 Fruit 4-5-locular; leaves deciduous, 4-12 cm long; petals 12-14 mm long; shrub to small tree 2-6 (-9) m tall

............ ............ ....15 Petals fused for part or all their lengths; fruit (4-) 5-locular; shrub or tree with leaves of various shape, evergreen or deciduous, these either < 6 mm long, linear and whorled, or > 12 mm long.

............ ............ ..........18 Leaves opposite or whorled, < 5 mm long, linear; [subfamily Ericoideae, tribe Ericeae]

............ ............ ............ 19 Leaves opposite, sessile, clasping at the base

............ ............ ............ 19 Leaves whorled (in 4s), petiolate

............ ............ ..........18 Leaves alternate or whorled, > 20 mm long.

............ ............ ............ ..20 Flowers 4-merous; fruits 4-locular; leaves with a series of fascicles of trichomes on the midrib below; [subfamily Ericoideae; tribe Rhodoreae]

............ ............ ............ ..20 Flowers 5-merous; fruits 5-locular; leaves not as above.

............ ............ ............ ....21 Leaves coriaceous, evergreen, shiny and dark green above.

............ ............ ............ ......22 Leaves sharply and distinctly serrate.

............ ............ ............ ........23 Pedicels slender, 7-10 mm long; filaments strongly curved just below the anthers; pith transversely diaphragmed; [subfamily Vaccinioideae; tribe Lyonieae]

............ ............ ............ ........23 Pedicels stout, 2-6 mm long; filaments straight; pith solid; [subfamily Vaccinioideae; tribe Gaultherieae]

............ ............ ............ ......22 Leaves entire, or obscurely and finely crenulate-serrulate.

............ ............ ............ ..........24 Capsules elongate, > 2× as long as broad, 8-18 mm long; [subfamily Ericoideae; tribe Rhodoreae]

............ ............ ............ ..........24 Capsules ovoid to globose or subglobose, about as long as broad, 5-8 mm long.

............ ............ ............ ............ 25 Leaves with a prominent vein running parallel to (and about 1 mm in from) the margin; [subfamily Vaccinioideae; tribe Lyonieae]

............ ............ ............ ............ 25 Leaves without a prominent marginal vein.

............ ............ ............ ............ ..26 Corolla saucer-shaped, 10-30 mm across; leaves entire; [subfamily Ericoideae; tribe Phyllodoceae]

............ ............ ............ ............ ..26 Corolla narrowly urceolate, 4-6 mm across; leaves finely crenulate-serrulate; [subfamily Vaccinioideae; tribe Lyonieae]

............ ............ ............ ............ ....27 Flower stalks with 2 opposite or subopposite subulate bractlets a little below the calyx; leaves glabrous below or short-pubescent on the midvein

............ ............ ............ ............ ....27 Flower stalks with 2 opposite or subopposite triangular bractlets near the base of the pedicel; leaf lower surface punctate with stalked red glands

............ ............ ............ ....21 Leaves membranaceous or subcoriaceous, deciduous or evergreen, if subcoriaceous and evergreen, then not shiny and dark green above.

............ ............ ............ ............ ......28 Capsules elongate, > 2× as long as broad, 7-23 mm long; [subfamily Ericoideae; tribe Rhodoreae]

............ ............ ............ ............ ......28 Capsules ovoid to globose or subglobose, about as long as broad, or broader than long, 2-7 mm long.

............ ............ ............ ............ ........29 Leaves (at least the larger) > 2.5 cm wide.

............ ............ ............ ............ ..........30 Pedicels with 2 bracteoles.

............ ............ ............ ............ ............ 31 Capsule broader than long; shrub; bracteoles just below the calyx; [subfamily Vaccinioideae; tribe Gaultherieae]

............ ............ ............ ............ ............ 31 Capsule longer than broad; tree; bracteoles generally near the middle of the pedicel; [subfamily Vaccinioideae; tribe Oxydendreae]

............ ............ ............ ............ ..........30 Pedicels without bracteoles.

............ ............ ............ ............ ............ ..32 Leaves entire to minutely serrulate; capsule sutures pale and thickened; [subfamily Vaccinioideae; tribe Lyonieae]

............ ............ ............ ............ ............ ..32 Leaves crenate; capsule sutures not thickened and pale; [subfamily Vaccinioideae; tribe Andromedeae]

............ ............ ............ ............ ........29 Leaves < 2.5 cm wide.

............ ............ ............ ............ ............ ....33 Leaves linear to narrowly lanceolate, 8× or more as long as wide. strongly revolute, strongly whitened beneath; [subfamily Vaccinioideae; tribe Andromedeae]

............ ............ ............ ............ ............ ....33 Leaves broader, not revolute or slightly so, not strongly whitened below.

............ ............ ............ ............ ............ ......34 Leaves whorled or alternate; corolla saucer-shaped, 10-20 mm across; [subfamily Ericoideae; tribe Phyllodoceae]

............ ............ ............ ............ ............ ......34 Leaves alternate; corolla narrowly urceolate, 2-8 mm across.

............ ............ ............ ............ ............ ........35 Pedicels with 2 bracteoles near the summit; [subfamily Vaccinioideae; tribe Gaultherieae]

............ ............ ............ ............ ............ ........35 Pedicels with 2 bracteoles near the base; [subfamily Vaccinioideae; tribe Lyonieae]

1 Stems creeping, the leaves 3-10 mm long, well-distributed along the stem; berries white; flowers 4-merous; [WV northwards]

1 Plant erect, the leaves few (< 10), clustered near the apex of the single stem.

..2 Leaves lanceolate or oblanceolate, normally 2-4× as long as wide (sometimes proportionately less narrow in stunted individuals; fruit a capsule, borne 1-several on an erect scape above the leaves.

....3 Leaves lanceolate (broadest below the middle), base rounded, striped with white or paler green along the major veins

....3 Leaves oblanceolate (broadest above the middle), base cuneate, solid dark green throughout

1 Plant creeping or sprawling, leaves scattered along the stems, or tufted at the base.

......4 Leaves 2-15 cm wide; leaves (2-) 3.5-15 cm long, rounded or subcordate at the base.

........5 Leaves dull green, with a pebbled texture, pilose (glabrate in age)

........5 Leaves bright shiny green (or purple), with a smooth texture, glabrous.

..........6 Leaves orbicular, the venation palmate, the apex rounded or with a slight point, finely serrate (4-8 teeth per cm), the teeth not prominently mucronate; flowers in racemes; [widespread in distribution]

..........6 Leaves broadly elliptic, the venation pinnate, the apex generally emarginate (slightly notched), coarsely serrate (1-4 teeth per cm), the teeth prominently mucronate; flowers solitary; [native to humid gorges along the escarpment between the Mountains and Piedmont, sometimes cultivated and becoming established elsewhere]

......4 Leaves 0-1.5 cm wide; leaves 0.5-3 cm long, cuneate at the base (at least widely so), glabrous (or bristly beneath in Gaultheria hispidula).

............ 7 Leaves linear, < 2 mm wide.

............ ..8 Leaves (3.3) 4-10 mm long; leaves lanceolate, averaging > 1.0 mm wide (oblanceolate and up to 2.5 mm wide if etiolated under leaf litter); leaves (in fresh material) herbaceous in texture, < 0.1 mm thick; leaves of sterile shoots ciliate along the margins at the base, usually also pubescent on the upper surface near the base, but the pubescence rarely extending > 1/3 of the way from the base to the tip; internodes usually > 1 mm long

............ ..8 Leaves 1-5 mm long (rarely to 7 mm long if etiolated under leaf litter); leaves ovate, averaging < 1.2 mm wide (lanceolate and up to 1.5 mm wide if etiolated under leaf litter); leaves (in fresh material) succulent in texture, up to 0.5 mm thick; leaves of sterile shoots lanose to densely pubescent on the upper surface at the base, the pubescence becoming sparser toward the tip of the leaf, but extending past the midpoint of the leaf and often its full length; internodes usually < 1 mm long

............ 7 Leaves broader, > 2 mm wide.

............ ....9 Leaves serrate or serrulate (sometimes inconspicuously so); [of pinelands of the Coastal Plain and (very rarely) lower Piedmont of se. VA southward].

............ ......10 Leaves (2-) 3-18 (-25) mm long, generally elliptic (less commonly ovate or obovate); angle of leaf base typically > 90 degrees; margins finely glandular mucronulate-crenulate, the teeth tightly appressed and therefore often obscure, the margin superficially entire; stems mostly prostrate (ascending in areas that have been long fire-suppressed); [widespread in NC and SC, rare in se. VA and e. GA]

............ ......10 Leaves (4-) 7-35 (-63) mm long, elliptic to obovate (less commonly elliptic-ovate); angle of leaf base typically < 90 degrees; margins glandular mucronulate-serrulate to serrulate-crenulate, the teeth apparent, especially toward the apex; stems often ascending to upright; [of Lexington County, SC]

............ ....9 Leaves entire; [of the Mountains of VA northward, except Vaccinium macrocarpon of bogs, as far south as se. sc. and sw. NC].

............ ........11 Leaves 10-30 mm long; leaves oblanceolate to obovate, the widest point past the middle; primary stems 1-3 mm in diameter; [of relatively dry, rocky habitats]

............ ........11 Leaves (3-) 5-10 (-18) mm long; leaves ovate or elliptic, the widest point below or at the middle; primary stems delicate; [of moist to distinctly boggy habitats].

............ ..........12 Leaf undersurface green, sparsely bristly; [of moist habitats]

............ ..........12 Leaf undersurface whitened, glabrous; [of saturated wetlands].

............ ............ 13 Leaves elliptic, broadest near middle, (5-) 7-10 (-18) mm long, (2-) 3-4 (-5) mm wide; leaves blunt-rounded and non-involute; pedicels with 2 green, leaf-like bracts 1-2 mm wide; berry 8-15 mm in diameter

............ ............ 13 Leaves ovate, broadest toward base, (3-) 5-6 (-9) mm long, (1-) 2-3 (-5) mm wide; leaves involute at least along the margins, thus making the leaf tip acute; pedicels with (0-) 2 (-5) reddish, scale-like bracts < 1 mm wide; berry 6-12 mm in diameter