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]

............ ..8 Leaves obovate, 1-2× as long as wide; fruit a red berry, borne on nodding axillary pedicels beneath the leaves; [subfamily Vaccinioideae; tribe Gaultherieae]

............ 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 yellow or reddish, 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

............ ............ ............ ....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 Leaves serrate.

..2 Leaf venation palmate, the leaf often lobed or at least pentagonal in shape (as well as serrate); plants climbing by leaf-opposed tendrils

..2 Leaf venation pinnate, the leaf neither lobed nor pentagonal; plants climbing by other mechanisms (see below).

....3 Plants climbing by axillary tendrils; [FL]

....3 Plants climbing by adventitious roots, by twining, or by growing through bark layers of Taxodium ascendens or Chamaecyparis thyoides; [collectively widespread in our region].

......4 Plants climbing by adventitious roots; leaf base cordate or subcordate, and also slightly to strongly oblique

......4 Plants climbing by twining, or by growing through bark layers of Taxodium ascendens or Chamaecyparis thyoides; leaf base cuneate, rounded, or cordate.

........5 Leaves strongly cordate at the base, 7-15 cm wide

........5 Leaves cuneate, rounded, or subcordate at the base, 0.3-8 cm wide.

..........6 Leaf blades mostly 6-13 cm long, 3-8 cm wide; plants climbing by twining

1 Leaves entire.

............ 7 Stems with well-developed prickles; tendrils paired, stipular (diverging from the leaf petiole above its base); [Monocots]

............ 7 Stems lacking prickles; tendrils either absent or (if present) not stipular and paired; [Eudicots or Basal Angiosperms].

............ ..8 Plant climbing by dense, reddish adventitious roots

............ ..8 Plant climbing by twining or by tendrils.

............ ....9 Plant climbing by tendrils

............ ....9 Plant climbing by twining.

............ ......10 Leaves elliptic or ovate, obviously longer than broad, most leaves > 1.4× as long as wide; leaf blade base narrowly cuneate, broadly cuneate, rounded, or subcordate.

............ ........11 Leaves 3-8 cm long, rounded to broadly cuneate at the base and rounded or obtuse at the apex; lateral leaf veins straight, parallel, not forking; inflorescence a terminal thyrse or panicle

............ ........11 Leaves 6-15 cm long, cuneate at the base and acuminate at the apex; lateral leaf veins forking at or beyond the middle; inflorescence a solitary, axillary flower

............ ......10 Leaves orbicular to very widely ovate, most leaves < 1.4× as long as wide; leaf blade base deeply cordate, subcordate, rounded, or broadly cuneate

............ ..........12 Leaf venation pinnate, but “pseudopalmate”, with 3 primary veins from the marginal point of attachment of the petiole, the 2 lateral veins then promptly rebranching (< 1 cm from the leaf base) into 2-3 prominent veins (the remainder of the venation pinnate along the midvein); basalmost pair of primary veins exposed (lacking leaf tissue) on their basal side for > 2 mm; leaf blade base deeply cordate; leaf with no tendency to lobing, the leaf outline convex from the base to the apex (except in the immediate vicinity of the petiole and sometimes immediately near a slightly acuminate apex

............ ..........12 Leaf venation palmate, with (3-) 5-9 primary veins from the marginal or peltate point of attachment of the petiole, these primary veins then rebranching well above the leaf base; basalmost pair of primary veins completely included within leaf tissue; leaf blade base cordate, subcordate, rounded, or broadly cuneate; leaf with a tendency to lobing, the leaf outline with 1 or more concave areas between the base and the apex (except Cissampelos of s. FL)