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Key to Ericaceae

Ericaceae

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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 or orange-yellow) 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)
                              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].
                                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]
                                         20 Flowers 4-merous; fruits 4-locular; leaves with a series of fascicles of trichomes on the midrib below; [subfamily Ericoideae; tribe Rhodoreae]
                                               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]
                                                 24 Capsules elongate, > 2× as long as broad, 8-18 mm long; [subfamily Ericoideae; tribe Rhodoreae]
                                                    25 Leaves with a prominent vein running parallel to (and about 1 mm in from) the margin; [subfamily Vaccinioideae; tribe Lyonieae]
                                                      26 Corolla saucer-shaped, 10-30 mm across; leaves entire; [subfamily Ericoideae; tribe Phyllodoceae]
                                           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]
                                                                     33 Leaves linear to narrowly lanceolate, 8× or more as long as wide. strongly revolute, strongly whitened beneath; [subfamily Vaccinioideae; tribe Andromedeae]

Key H: woody plants with whorled leaves

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1 Leaves tiny, bract-like, triangular, 6-14 (-17) per node
1 Leaves either needle-like, scale-like, or flattened and large, (2-) 3-4 (-6) per node.
  2 Leaves needle-like or scale-like, terete, angled, or flat in ×-section, < 2 cm long; leaves (2-) 3-4 (-6) per node
  2 Leaves flat, > 3 cm long; leaves (2-) 3 per node; [Eudicots].
    3 Plant a subshrub, < 3 dm tall, with < 10 leaves per stem.
      4 Leaves entire, broadly elliptic; flowers numerous, in a hemispherical head, subtended by 4 large white bracts
      4 Leaves serrate, narrowly ovate or narrowly obovate; flowers (1-) 2-8 in a long-peduncled umbel or corymb, not subtended by bracts
    3 Plant a shrub or tree, > 3 dm tall, with many > 10 leaves per stem.
          6 Leaves cordate at base, about as long as wide; medium to large tree.
             7 Flowers white to yellow; capsules linear, >10× as long as wide; leaf undersurface with curly simple hairs; nectar glands present in the main vein axils on the undersurface of the leaf (visible from the underside or the upperside in fresh leaves and herbarium specimens as a triangle 1-4 mm on a side)
             7 Flowers lavender; capsules ellipsoid, < 2× as long as wide; leaf undersurface with branched (dendritic or stellate) hairs; nectar glands absent
          6 Leaves cuneate to rounded at base; leaves > 1.5× as long as wide; shrub to small tree.
               8 Leaves rounded or retuse at the tip (at least some obviously rounded in Pittosporum).
                 9 Fruit a large, globose berry (2-8 cm in diameter), pale brown in color when mature, the surface roughened in texture; petioles with a decurrent, adaxial wing forming a groove; sepals rusty tomentose
                 9 Fruit a capsule, dehiscing alonge 1 or 5 sutures; petioles lacking a decurrent, adaxial wing forming a groove; sepals variously glabrous to pubescent, but not rusty tomentose.
                   10 Ovaries 2-carpellate; capsules dehiscing along one major adaxial suture, appearing berry-like before dehiscence, the seeds often surrounded by a glutinous material
                     11 Leaves lanceolate or oblong-elliptic to narrowly ovate (> 2.5× as long as wide), the secondary venation not prominent nor arching-parallel (except Decodon); inflorescences axillary or terminal; flowers pink or white.
                       12 Inflorescences axillary; flowers pink; leaves thin and herbaceous, with prominent secondary veins arching parallel with the margin, also with branching hairs on the abaxial leaf midvein; plants with arching stems, these often tip-rooting; [native plants of wetlands]
                       12 Inflorescences terminal or axillary; flowers pink or white; leaves thick and leathery, lacking prominent secondary veins; plants not tip-rooting nor with branching hairs on the midvein; [exotics of uplands or wetlands, persistent or weakly naturalized]
                          13 Fruit follicles; flowers variously colored (including white), showy and salverform; inflorescence terminal.
                            14 Plants trees, 2-60 m tall, with a single or multiple stem(s); latex milky; flowers white or cream colored, the anthers not connivent and not adhering to stigmas; [uncommon non-natives, s. FL]
                            14 Plants shrubs, 10-40 dm tall, much branched from the base; latex clear; flowers white, pink, or red, the anthers connivent and adhering to the stigmas; [commonly cultivated in our area (and sometimes persistent), particularly near the coast; NC s. to FL, w. to TX]
                     11 Leaves ovate (< 2× as long as wide), the secondary venation prominent and arching-parallel; inflorescences terminal; flowers white, greenish-yellow, red, or orange.
                              15 Flowers in a spherical or hemispherical head; corollas white or greenish-yellow; fruit a globose cluster of nutlets (dry)

Key P1: herbaceous dicots with alternate, simple, and unlobed leaves on the stem

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1 Inflorescence an involucrate head subtended by phyllaries, the heads solitary or many and variously arrayed in secondary inflorescences, the ovary inferior, the corolla connate and tubular at least basally, the calyx absent, the stamens 5, the fruit a cypsela
1 Inflorescence, flower, and fruit structure various, but not with the combination of features as above (sometimes the flowers in a head, e.g. Eryngium in APIACEAE, but then with other features differing, such as stamens 4, or green calyx present, or fruit a schizocarp of mericarps, etc.).
  2 Perianth uniseriate (represented only by undifferentiated tepals or sepals; look at the front and back of the flowers for two layers) or completely absent; flowers usually unisexual, less commonly bisexual).
    3 Inflorescence a cyathium, consisting of a single pistillate flower (reduced to a single 3-carpellate pistil) and 2 or more staminate flowers (each reduced to 1 stamen), borne in a cup-like involucre, the involucre bearing pointed or rounded glands, these sometimes brightly colored and petaloid, mimicking an individual flower (the cyathia then secondarily arranged in terminal cymes, or solitary and axillary, etc.); fresh plants with milky juice; fruit a 3-lobed, 3-locular capsule
    3 Inflorescence not a cyathium (and staminate or bisexual flowers with > 1 stamen; fresh plants lacking milky juice (except Stillingia in EUPHORBIACEAE); fruit various, not as above.
        5 Leaf teeth rounded to subacute, resembling shallow lobes, irregular, few (mostly < 6 per leaf side).
          6 Fruit a single-seeded achene or utricle; [plants of various disturbed or saline, usually sunny habitats]
          6 Fruit a 3-lobed, circumscissilely dehiscent capsule; [plants native of rich moist shaded forests or exotics in suburban woodlands]
        5 Leaf teeth sharp to crenate, not lobe-like, regular, many (mostly > 10 per leaf side).
             7 Leaf bases cuneate (or strongly oblique in Begonia, with one leaf base usually being cuneate, the other variously rounded or cordate).
               8 Flowers typically with 2 or 4 (-5) showy, white-colored tepals; leaves sometimes variegated; fruit unequally or subequally 3-winged capsules; [ornamental waifs or uncommon non-natives]
               8 Flowers cyathia, not merely bearing showy tepals; leaf not variegated but sometimes bearing darkened red or black splotches; fruit capsules, but these not conspicuously winged; [natives and non-natives, usually not ornamental]
                 9 Styles 3; fruit a 3-lobed, 3-carpellate capsule (1 carpel sometimes aborting); inflorescence either a terminal or leaf opposed raceme, or a dense axillary condensed cyme with conspicuous toothed bracts subtending the flowers
                 9 Styles 1 or 2; fruit either an achene or a multiple of achenes; inflorescence either an axillary dense cyme (almost a head), or an axillary spike with glomerules, or a terminal or axillary panicle.
                   10 Styles 2; inflorescence a dense axillary cyme (almost a head); fruit a multiple of achenes; plant lacking stinging hairs; [exotic plant of weedy situations]
                   10 Style 1; inflorescence an axillary spikes with glomerules, or a terminal or axillary panicle; plant either with stinging hairs or not; [plant a rare exotic (Boehmeria nivea) or a native of moist forests (Boehmeria cylindrica, Laportea)]
                     11 Ovary inferior (flowers epigynous, the ovary sitting below the perianth and androecium) or half-inferior (perigynous, the ovary sitting level with the remaining floral parts).
                       12 Leaf base cordate; calyx 3-lobed, fused into a bilaterally symmetrical, curved brown or yellowish tube; fruit a capsule
                       12 Leaf base cuneate, rounded, or truncate; calyx of 3-4-5 distinct sepals, radially symmetrical, white or yellow; fruit a dry, nutlike drupe or an achene.
                          13 Leaves subsessile or very short petiolate, elliptic or narrowly elliptic, broadest near the middle; [native]
                          13 Leaves distinctly petiolate, rhombic, widest near the base; [rarely naturalized exotics].
                              15 Inflorescence a leaf-opposed spike or raceme, the inflorescence arising opposite of stem leaves (except Saururus, whose spikelike racemes are leaf-opposed and/or terminal); flowers visually white from white petaloid sepals, white bracts, or white stamens.
                                16 Sepals present, 4 or 5; petaloid, white; carpels 1 to many (-12); stamens 4 to many (-25); fruit a berry or an apically 2-lobed achene (as in Petiveria); leaf bases cuneate or rounded (but not cordate); [Eudicots].
                              15 Inflorescence not leaf opposed, instead arising with stem leaves (axillary) or terminal, the inflorescence not spikes nor racemes, instead either simpler (single axillary or glomerules of flowers) or more complexly branched (terminal or axilary panicles or terminal complex cymes); flowers white, reddish, scarious, or greenish.
                                             22 Sepals petaloid, pink and relatively conspicuous (although the sepals ca. 1-3 mm in length); plants prostrate to somewhat ascending annuals; leaves opposite or nearly whorled; achenes muricate
                                             22 Sepals not petaloid, inconspicuous, green or greyish in color; plants prostrate or erect, annual or perennial; leaves alternate OR either alternate or opposite (Amaranthaceae); achenes variously textured (smooth or textured, sometimes reticulate or verrucose, but rarely muricate).
  2 Perianth biseriate (represented by differentiated whorls of sepals and petals, the sepals usually green or drab in color, the petals often brightly colored); flowers nearly always bisexual (there are exceptions).
                                                        27 Inflorescence not a dense, leaf-opposed spike, instead a terminal head or variously axillary or terminal (the flowers solitary or not, but not in a dense spike).
                                                          28 Flowers yellow; stamens numerous (15+), monomorphic or heteromorphic (inner and outer of differing length), conspicuously exerted from the flowers, often surpassing the ovary; leaves basally lobed or unlobed (often a mix in M. floridana and M. oligosperma)
                                                          28 Flowers blue or white; stamens fewer (usually < 10), monomorphic, if exerted, the ovary usually still apparent; leaves unlobed.
                                                                   32 Corolla bilaterally symmetrical (zygomorphic), petals connate, at least basally (except distinct in VIOLACEAE); fruit a capsule or legume (the capsule conspicuously spiny in Krameria).
                                                                     33 Petals connate (at least basally), 4, 5, 6, 7, or 8; carpels 1, 2, 4, 5, or 6 (rarely 3 in Reseda in RESEDACEAE); fruit a legume or 1-, 2-, or 5-loculed capsule (except a 1-seeded indehiscent pod in Krameria in KRAMERIACEAE).
                                                                                38 Pistil 2-carpellate; capsule 2 locular, opening gradually or not at all; inflorescence a terminal spike, raceme or panicle (or solitary, axillary flowers in Chaenorrhinum in PLANTAGINACEAE and Krameria in KRAMERIACEAE).
                                                                                    40 Stamens 4; corolla with a distinct spur or sac at the base between the the 2 lower calyx lobes (except not spurred in Digitalis and Schwalbea); capsule loculicidal (only at the summit in Antirrhinum and Chaenorrhinum, and septicidal in Schwalbea); pubescence of the stem and leaves neither gland-tipped (except in Antirrhinum and Chaenorrhinum) nor dendritically branched.
                                                                                             44 Pistil 1, with 1-to many carpels (in many MALVACEAE, the carpels loosely united in a ring [of more than 5] around the single style/stigma); fruit either a 1-, 2-, 3-, 5-, 6-, or 10-locular capsule, or a silique/silicle, or a ring of mericarps.
                                                                                                                                  61 Plants usually strongly gray or white-colored and villous, growing in short, suffrutescent mounds or mats; leaves densely pubescent (hairs densely appressed adaxially, tomentose abaxially); inflorescence of solitary flowers or extra-axillary, never scirpioid; corolla lavender or whitish-lavender, the lobes 1.8-3.0 (-4.5) mm long, broadly rounded; [s. TX, westward; primarily of the Trans-Pecos region]
                                                                                                                                  61 Plants variously glabrous or pubescent (sometimes villous), usually herbaceous, occasionally suffrutescent and mound or mat-forming; inflorescence variously elongate or racemose, often scirpioid (curved or coiled on one side of the inflorescence axis; e.g., Heliotropium), occasionally solitary (e.g., Euploca, in part; although in this case the leaves of the shrubby Euploca are significantly narrower); corolla variously colored (including lavender); [plants collectively widespread, including TX]

Key Q: herbaceous dicots with whorled leaves on the stem {add [Platycodon] CAMPANULACEAE}

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  2 Cauline leaves essentially sessile, and also palmately cleft to the base, and further lacerately divided into linear or oblanceolate segments
  2 Cauline leaves petiolate, with 3-5, sessile or petiolulate, ovate, elliptic, or obovate leaflets (these serrate and sometimes with additional lobes).
    3 Inflorescence a spherical umbel of many flowers; fruit a drupe with 2-3 seeds; stem leaves 3-5
      4 Leaflets 3 (-5), sessile or subsessile, the petiolules 0-3 mm long; larger leaflets 4-8 cm long, 0.5-2.5 cm wide, averaging about 2.5× as long as wide, the apex obtuse to acute; fruit yellow-green when ripe, longitudinally winged and ribbed in ×-section; petals white (rarely tinged with pink); inflorescence nodding in bud; underground storage organ a spherical tuber
      4 Leaflets (3-) 5, petiolulate, the petiolules (7-) 10-25 mm long; larger leaflets 6-15 cm long, 3.5-7 cm wide, averaging about 1.8× as long as wide, the apex acuminate; fruit bright red when ripe, smoothly elliptical in ×-section; petals light green; inflorescence erect in bud; underground storage organ an +/- elongate root, this vertical or horizontal, and sometimes branched
    3 Inflorescence of single terminal flowers on the 1-several branches; fruit an aggregate of achenes; stem leaves 3
1 Cauline leaves simple.
        5 Inflorescence an involucrate head subtended by phyllaries, heads solitary or many, variously arrayed in secondary inflorescences; fruit a cypsela
        5 Inflorescence various, but not as above; fruit various, not as above (sometimes the flowers tightly grouped, but then with other features differing, such as stamens 4, or green calyx present, or fruit a schizocarp of mericarps, etc.).
          6 Fruit a 3-lobed, 3-locular capsule; inflorescence a cyathium, consisting of a single pistillate flower (reduced to a single 3-carpellate pistil) and 2 or more staminate flowers (each reduced to 1 stamen), borne in a cup-like involucre, the involucre bearing pointed or rounded glands, these sometimes brightly colored and petaloid, mimicking an individual flower (the cyathia then secondarily arranged in terminal cymes, or solitary and axillary, etc.); fresh plants with milky juice
          6 Fruit various, not as above; inflorescence not a cyathium (and staminate or bisexual flowers almost always with > 1 stamen); fresh plants lacking milky juice.
             7 Leaves succulent, the terminal whorls closely juxtaposed; pistils 4-5; fruit an aggregate of follicles
             7 Leaves herbaceous, thin in texture, whorls separated; pistil 1, of 2-5 fused carpels; fruit a capsule, achene, or drupe.
               8 Larger whorled leaves on a plant < 10 mm wide [some taxa keyed here and under the second lead].
                   10 Leaves markedly variable in shape or size in each whorl; fruit a capsule; petals 5
                   10 Leaves similar in size and shape in each whorl; fruit dry or fleshy, indehiscent; petals (3-) 4
                     11 Corolla radially symmetrical, the petals separate; carpels 2, 3, or 5; stamens 5, 10, or many.
                          13 Inflorescence an axillary umbel; leaves narrowly linear and more than 10× as long as wide, > 20 mm long and < 2 mm wide; whorls of 3-6 leaves
                          13 Inflorescence a terminal cyme, raceme, panicle, or umbel; leaves as above, or broader in shape, narrower, or shorter; whorls of 3-16 leaves.
               8 Larger whorled leaves on a plant > 10 mm wide.
                                    18 Inflorescence various, but not as above; perianth of 2 whorls (the calyx often obsolete in Galium in RUBIACEAE), 3-, 4-, 5-, 6-, or 7-merous; stamens 2-7; [plants of dry-mesic to very wet habitats].
                                           21 Corolla pink-purple, 6-merous, the petals separate and borne on the edge of a hypanthium; stamens 8, 10, or 12; [plants of wetlands]
                                           21 Corolla white, yellow, or greenish, 4-, 5-, or 7-merous, the petals fused at least basally into a tube (falling as a unit), not on a hypanthium; stamens 2, 4, 5, or 7; [plants of mesic habitats].
                                               23 Petals yellowish-white, with prominent green streaks; biennial or monocarpic plant, 10-30 dm tall when fertile; leaves 15-35 cm long
                                               23 Petals white or yellow; perennial plants, 1-15 dm tall; leaves 1-15 cm long.