VIOLACEAE, the Violet Family

Herbs with simple, alternate or basal leaves, and conspicuous irregular flowers with a spur (except in the first species); sepals, petals, and stamens each 5; ovary 1-celled.

1a. Flowers regular or nearly so, greenish-white, axillary; erect plant with leafy stem (3-5 dm. high; spring) Green Violet, Hybanthus concolor.
1b. Flowers irregular, blue, yellow, or white, conspicuous (Violet) — 2.
2a. Plant stemless, the flowers all on leafless stalks and the leaves all basal (spring or early summer) — 3.
2b. Stems leafy (spring and summer) — 17.
3a. Petals yellow Round-leaved Violet, Viola rotundifolia.
3b. Petals blue, violet, or white — 4.
4a. Principal leaves at time of flowering deeply lobed — 5.
4b. Leaves oblong, ovate, or triangular, not narrowed to the petiole, and frequently sharply toothed or incised near the base — 7.
4c. Leaves narrowly lanceolate, tapering to the base Violet, Viola lanceolata.
4d. Leaves heart-shape or kidney-shape, not lobed — 8.
5a. Lateral petals bearded — 6.
5b. Lateral petals not bearded Bird-foot Violet, Viola pedata.
6a. Leaves divided to the base into linear segments Bird-foot Violet, Viola pedatifida.
6b. Leaves irregularly divided into broader segments Hand-leaf Violet, Viola palmata.
7a. Leaves ovate-oblong, pubescent Violet, Viola fimbriatula.
7b. Leaves triangular-lanceolate, usually somewhat dilated at base, nearly or quite glabrous Violet, Viola sagittata.
8a. Flowers violet or blue (rarely white-flowered plants are found with the typical blue-flowered ones) (Blue Violets) — 9.
8b. Flowers white, the 3 lower petals marked with purple (White Violets) — 14.
9a. Lateral petals bearded — 10.
9b. Lateral petals beardless Great-spurred Violet, Viola selkirkii.
10a. Foliage glabrous — 11.
10b. Petioles and lower surface of leaves pubescent — 13.
11a. Beard of the lateral petals with a knob at the tip of each hair Blue Violet, Viola cucullata.
11b. Beard of the lateral petals not knobbed — 12.
12a. Spurred petal hairy Wood Violet, Viola affinis.
12b. Spurred petal glabrous Blue Violet, Viola papilionacea.
13a. Spurred petal villous Blue Violet, Viola septentrionalis.
13b. Spurred petal glabrous, or with a few scattered hairs Common Blue Violet, Viola sororia.
14a. Leaf-blade obviously pubescent — 15.
14b. Leaf-blade glabrous or very nearly so — 16.
15a. Lateral petals bearded Sweet White Violet, Viola incognita.
15b. Lateral petals not bearded White Violet, Viola renifolia.
16a. Leaf-blades strictly glabrous Sweet White Violet; Viola pallens.
16b. Leaf-blades with some minute white hairs on the upper surface near the base Sweet White Violet, Viola blanda.
17a. Stipules large and leaf-like, deeply pinnatifid and nearly or quite as long as the petioles — 18.
17b. Stipules small, inconspicuous, entire or toothed, and much shorter than the petiole — 19.
18a. Leaves serrate; flowers 1.5-2.5 cm. wide (1-3 dm. high; flowers of various colors) Pansy, Viola tricolor.
18b. Upper leaves entire or nearly so; flowers about 1 cm. wide (1-2 dm. high; flowers bluish-white) Wild Pansy, Viola rafinesquii.
19a. Petals yellow (1-4 dm. high) (Yellow Violet) — 20.
19b. Petals violet, blue, or white — 21.
20a. Foliage villous-pubescent Yellow Violet, Viola pubescens.
20b. Foliage nearly or quite glabrous Yellow Violet, Viola scabriuscula.
21a. Stipules entire (2-4 dm. high) Canada Violet, Viola canadensis.
21b. Stipules toothed — 22.
22a. Lateral petals not bearded (1-2 dm. high) Long-spurred Violet, Viola rostrata.
22b. Lateral petals bearded — 23.
23a. Flowers white or nearly white (1-3 dm. high) Pale Violet, Viola striata.
23b. Flowers blue (about 1 dm. high) — 24.
24a. Leaves smooth Dog Violet, Viola conspersa.
24b. Leaves pubescent Sand Violet, Viola arenaria.


CACTACEAE, the Cactus Family

Fleshy, jointed leafless plants, armed with numerous thorns; flowers large (5-10 cm. wide), yellow, with about 10 petals and numerous stamens.

One species in Michigan, on the shores of Lake Michigan; flowers in summer Prickly Pear, Opuntia rafinesquii.


THYMELAEACEAE, the Mezereum Family

Shrubs, with simple alternate entire leaves, and small yellowish flowers in clusters, opening before the leaves; petals none, the sepals somewhat petal-like.

One species in Michigan, 5-15 dm. tall, with very tough bark Leatherwood, Dirca palustris.


ELAEAGNACEAE, the Oleaster Family

Shrubs, with opposite, silvery-pubescent, simple, entire leaves, and small clusters of inconspicuous yellow flowers in spring.

One species in Michigan, 1-2 m. high Buffalo Berry, Shepherdia canadensis.


LYTHRACEAE, the Loosestrife Family

Herbs or shrubs, with opposite or alternate entire leaves; receptacle cup-shape or tubular, bearing the 5-7 petals and sepals at its margin, and the 6-12 stamens on its inner surface; ovary superior.

1a. Stem shrubby (aquatic, stems 1-3 m. long; flowers pink, summer) Water Loosestrife, Decodon verticillatus.
1b. Stem herbaceous (4-10 dm. high; flowers purple, summer) — 2.
2a. Flowers solitary in the axils; leaves mostly alternate Loosestrife, Lythrum alatum.
2b. Flowers in terminal panicles; leaves opposite or whorled Loosestrife, Lythrum salicaria.


MELASTOMACEAE, the Melastoma Family

Herbs, with opposite leaves with 3-5 principal veins; receptacle urn-shape, bearing 4 sepals and 4 petals at its edge; stamens 8; ovary 4-celled, superior.

One species in Michigan, 3-4 dm. high, with purple flowers in late summer Meadow Beauty, Rhexia virginica.


ONAGRACEAE, the Evening Primrose Family

Herbs with opposite or alternate simple leaves and regular flowers; sepals and petals each 4 (or 2 in one genus), stamens 8 (or 2 in one genus), attached to the summit or inside of a tubular receptacle; ovary 2-4-celled, inferior.

1a. Aquatic plant of shallow water or muddy ground, with prostrate stem (flowers minute, axillary; petals small or none, summer) Water Purslane, Ludvigia palustris.
1b. Land plants with erect or ascending stems — 2.
2a. Petals minute, greenish (3-8 dm. high; late summer) False Loosestrife, Ludvigia polycarpa.
2b. Petals yellow — 3.
2c. Petals white, pink, purple, or red — 9.
3a. Sepals borne at the summit of the ovary (5-10 dm. high; summer) False Loosestrife, Ludvigia alternifolia.
3b. Sepals borne at the summit of the slender tubular receptacle, which is prolonged beyond the ovary — 4.
4a. Stamens all equal in length (Evening Primrose) — 5.
4b. The alternate stamens longer (3-8 dm. high; summer) (Sundrops) — 8.
5a. Leaves deeply dentate or pinnatifid (2-5 dm. high; early summer) Evening Primrose, Oenothera laciniata.
5b. Leaves entire or undulate or finely toothed (5-12 dm. high; summer) — 6.
6a. Hairs on the stem with broad reddish bases Evening Primrose, Oenothera muricata.
6b. Hairs on the stem none, or without swollen bases — 7.
7a. Stem and foliage glabrous, or with sparse spreading hairs Evening Primrose, Oenothera biennis.
7b. Stem and foliage densely but closely appressed-pubescent Evening Primrose, Oenothera rhombipetala.
8a. Petals 5-10 mm. long Sundrops, Oenothera pumila.
8b. Petals 14 mm. long or more Sundrops, Oenothera fruticosa.
9a. Petals 2, reverse heart-shape, stamens 2 (flowers small, white, summer) (Enchanter's Nightshade) — 10.
9b. Petals 4; stamens 4 or 8 — 12.
10a. Leaves rounded at the base, denticulate (3-8 dm. high; fruit prickly) Enchanter's Nightshade, Circaea lutetiana.
10b. Leaves cordate at the base — 11.
11a. Fruit 2-celled, bristly (2-4 dm. high) Enchanter's Nightshade, Circaea intermedia.
11b. Fruit 1-celled, with soft hairs (delicate plant 2 dm. high, or less) Enchanter's Nightshade, Circaea alpina.
12a. Petals entire (summer) — 13.
12b. Petals notched at the end (flowers white or pinkish, less than 1 cm. broad, in summer) (Willow Herb) — 15.
13a. Flowers 2-3 cm. wide, purple (7-20 dm. high) Fireweed, Epilobium angustifolium.
13b. Flowers about 1 cm. wide — 14.
14a. Flowers red (2-5 dm. high) Gaura, Gaura coccinea.
14b. Flowers white, turning pink when old Gaura, Gaura biennis.
15a. Leaves entire, the margins usually somewhat revolute — 16.
15b. Leaves toothed, flat (4-9 dm. high) — 18.
16a. Plant densely pubescent with spreading hairs (3-8 dm. high) Willow Herb, Epilobium molle.
16b. Plant pubescent with appressed or incurved hairs — 17.
17a. Leaves linear, the margin revolute (3-5 dm. high) Willow Herb, Epilobium densum.
17b. Leaves narrowly lanceolate, not revolute (2-4 dm. high) Willow Herb, Epilobium palustre.
18a. Seeds tipped with a tuft of reddish-brown hairs Willow Herb, Epilobium coloratum.
18b. Seeds tipped with a tuft of white hairs Willow Herb, Epilobium adenocaulon.


HALORAGIDACEAE, the Water Milfoil Family

Aquatic or marsh herbs, with alternate, opposite, or whorled leaves, and small, inconspicuous terminal or axillary flowers, frequently without petals (summer).

1a. Leaves none, or else very small and inconspicuous Water Milfoil, Myriophyllum tenellum.
1b. Leaves alternate (1-4 dm. high) Mermaid Weed, Proserpinaca palustris.
1c. Leaves opposite or whorled — 2.
2a. Leaves entire (2-4 dm. high) Mare's-tail, Hippuris vulgaris.
2b. Leaves toothed or dissected (Water Milfoil) — 3.
3a. Flowers in the axils of foliage leaves — 4.
3b. Flowers in terminal spikes, subtended by bracts — 5.
4a. Flowers above water, subtended by toothed or entire leaves Water Milfoil, Myriophyllum heterophyllum.
4b. Flowers submerged, subtended by dissected leaves Water Milfoil, Myriophyllum farwellii.
5a. Flowers solitary or in pairs at each joint of the spike Water Milfoil, Myriophyllum alternifolium.
5b. Flowers several at each joint of the spike — 6.
6a. Bracts deeply pinnatifid Water Milfoil, Myriophyllum verticillatum var. pectinatum.
6b. Bracts entire or toothed Water Milfoil, Myriophyllum spicatum.


ARALIACEAE, the Sarsaparilla Family

Herbs or thorny shrubs, with alternate or whorled leaves, and small flowers in umbels; sepals 5, minute; petals and stamens each 5; ovary inferior, with 2-5 styles, ripening into a berry.

1a. Leaves simple, palmately lobed (thorny shrub; flowers greenish-white, in panicles, in June) Devil's Club, Fatsia horrida.
1b. Leaves once compounded, whorled (umbel one, terminal) — 2.
1c. Leaves twice or thrice compounded (umbels several) — 3.
2a. Leaflets sessile; flowers white, in spring (1-2 dm. high) Dwarf Ginseng, Panax trifolium.
2b. Leaflets stalked; flowers greenish, in summer (2-5 dm. high) Ginseng, Panax quinquefolium.
3a. Stem and petioles spiny or bristly (flowers white, summer) — 4.
3b. Stem and petioles smooth or a little pubescent (flowers greenish-white) — 5.
4a. Shrubby, with stout thorns (1-3 m. high) Hercules' Club, Aralia spinosa.
4b. Herbaceous, with slender bristles (4-10 dm. high) Bristly Sarsaparilla, Aralia hispida.
5a. Stem-leaves present; leaflets cordate at the base (8-15 dm. high; summer) Spikenard, Aralia racemosa.
5b. Leaf and flower-stalk arising from the ground; leaflets acute at the base (2-4 dm. high; spring) Wild Sarsaparilla, Aralia nudicaulis.


UMBELLIFERAE, the Parsley Family

Herbs, with alternate, usually compound leaves, the petioles dilated at the base; flowers small, in umbels or heads; sepals 5, minute or even wanting; petals and stamens each 5; ovary inferior, with 2 styles, ripening into a dry fruit.

1a. Leaves simple (flowers in summer) — 2.
1b. Leaves compound, or at least deeply cleft — 4.
2a. Leaves linear, sword-shape (4-10 dm. tall; flowers greenish-white) Rattlesnake Master, Eryngium yuccifolium.
2b. Leaves kidney-shape or almost circular (stems creeping, about 1 dm. high; flowers white) (Water Pennywort) — 3.
3a. Leaves peltate, attached by the center Water Pennywort, Hydrocotyle umbellata.
3b. Leaves not peltate, attached by the margin Water Pennywort, Hydrocotyle americana.
4a. Flowers yellow or purple — 5.
4b. Flowers white or greenish — 13.
5a. Leaf-segments entire (4-8 dm. high) — 6.
5b. Leaf-segments toothed or incised — 7.
6a. Leaf-segments filiform (summer) Fennel, Foeniculum vulgare.
6b. Leaf-segments ovate to lanceolate Golden Alexander, Taenidia integerrima.
7a. Leaves pinnately compound; some of the leaflets incised or pinnatifid — 8.
7b. Leaves ternately compound; the segments crenate or serrate — 9.
7c. Leaves deeply palmately cleft or divided; flowers in head-like umbels — 18a.
8a. Leaf-segments obtuse, rounded, or cordate at the base (6-15 dm. high; summer) Wild Parsnip, Pastinaca sativa.
8b. Leaf-segments narrowed to the base (4-8 dm. high; spring) Prairie Parsley, Polytaenia nuttallii.
9a. Terminal leaflets conspicuously stalked, their total length, including stalk, at least 50% greater than the length of the lateral leaflets (Meadow Parsnip) — 10.
9b. Terminal leaflets not conspicuously stalked, their total length, including stalk, about equaling the lateral leaflets (4-8 dm. high; late spring) (Golden Alexander) — 12.
10a. Flowers purple (4-8 dm. high; early summer) Meadow Parsnip, Thaspium aureum var. atropurpureum.
10b. Flowers yellow — 11.
11a. Stem-leaves once-ternate; leaflets finely serrate (4-8 dm. high; early summer) Meadow Parsnip, Thaspium aureum.
11b. Many stem-leaves 2-3-ternate; leaflets coarsely serrate or incised (6-12 dm. high; early summer) Meadow Parsnip, Thaspium barbinode.
12a. Basal and lower stem-leaves 2-3-ternate Golden Alexander, Zizia aurea.
12b. Basal leaves simple; stem-leaves once-ternate Golden Alexander, Zizia cordata.
13a. Leaves once-pinnate (or the submerged leaves decompound, if present) (summer) — 14.
13b. Leaves ternately, palmately, or 2-3-pinnately compound — 16.
14a. Leaflets mostly ovate or ovate-lanceolate, some of them coarsely incised (3-9 dm. high) Water Parsnip, Berula erecta.
14b. Leaflets linear to oblong, serrate to nearly entire, not incised (6-15 dm. high) — 15.
15a. Leaflets entire, or with a few low remote teeth Cowbane, Oxypolis rigidior.
15b. Leaflets finely but sharply serrate Water Parsnip, Sium cicutaefolium.
16a. Leaves principally basal, decompound; flowers in early spring (1-2 dm. high) Harbinger of Spring, Erigenia bulbosa.
16b. Leaves principally on the stem — 17.
17a. Leaves palmately or ternately once-compound — 18.  
17b. Leaves 2-3 times compound or decompound — 24.
18a. Flowers short-pedicelled, crowded in head-like umbels, greenish; ovary bristly (4-9 dm. high; early summer) (Black Snakeroot) — 19.
18b. Flowers in open umbels, white — 22.
19a. Styles short, not projecting beyond the bristles of the mature fruit — 20.
19b. Styles long, projecting beyond the bristles of the fruit, and recurved — 21.
20a. Staminate flowers on pedicels 3-4 mm. long, equaling or barely exceeding the fruit Black Snakeroot, Sanicula trifoliata.
20b. Staminate flowers short-pedicelled, concealed among the fruits Black Snakeroot, Sanicula canadensis.
21a. Fruit short-stalked, 4 mm. long or less Black Snakeroot, Sanicula gregaria.
21b. Fruit sessile, 6-7 mm. long Black Snakeroot, Sanicula marilandica.
22a. Umbel unsymmetrical, its branches irregular in length; plant slender (3-8 dm. tall; early summer) Honewort, Cryptotaenia canadensis.
22b. Umbel symmetrical with regular branches; plants tall and stout — 23.
23a. Stem and leaves very pubescent (10-25 dm. high; summer) Cow Parsnip, Heracleum lanatum.
23b. Stem and leaves glabrous or nearly so (5-15 dm. high; early summer) Masterwort, Imperatoria ostruthium.
24a. Ovary and fruit bristly (4-10 dm. high) — 25.
24b. Ovary and fruit smooth or winged, never bristly — 27.
25a. Umbels loose, open, few-flowered; woodland plants blooming in spring (Sweet Cicely) — 26.
25b. Umbels densely flowered; weedy plants blooming from summer to fall Wild Carrot, Daucus carota.
26a. Stem villous-pubescent Sweet Cicely, Osmorhiza claytoni.
26b. Stem glabrous except at the joints Sweet Cicely, Osmorhiza longistylis.
27a. Leaflets merely serrate (flowers in summer) — 28.
27b. Leaflets coarsely incised, so that the leaf appears dissected — 30.
28a. Umbel densely pubescent (8-15 dm. high) Angelica, Angelica villosa.
28b. Umbel smooth — 29.
29a. Leaf-segments broadly ovate (8-15 dm. high) Angelica, Angelica atropurpurea.
29b. Leaf-segments lanceolate (8-15 dm. high) Water Hemlock, Cicuta maculata.
29c. Leaf-segments linear (4-10 dm. high) Water Hemlock, Cicuta bulbifera.
30a. Principal branches of the umbel 2-5; fruit linear-oblong; woodland plants blooming in spring (2-4 dm. high) Chervil, Chaerophyllum procumbens.
30b. Principal branches of the umbel 7 or more; fruit ovate to broadly elliptical (summer) — 31.
31a. Native plants, growing in swamps (5-15 dm. high) Hemlock Parsley, Conioselinum chinense.
31b. Introduced plants, in waste places and along roads — 32.
32a. Stems conspicuously spotted with purple (5-15 dm. high) Poison Hemlock, Conium maculatum.
32b. Stems not spotted with purple (2-5 dm. high) Caraway, Carum carvi.


CORNACEAE, the Dogwood Family

Trees, shrubs, or herbs, with alternate leaves and small flowers in rather crowded rounded or flattened clusters; sepals 4, minute; petals and stamens each 4; ovary inferior, ripening into a berry. In one genus the flowers are minute and greenish, with 5 sepals and petals minute or none.

1a. Leaves alternate — 2.
1b. Leaves opposite — 3.
2a. Flowers white, conspicuous, in flattened clusters (shrubs 2-4 m. high; flowers in late spring) Dogwood, Cornus alternifolia.
2b. Flowers greenish, inconspicuous, in small axillary clusters (tree; flowers in spring) Sour Gum, Nyssa sylvatica.
3a. Flower clusters small and dense, surrounded by a showy involucre of 4 bracts, resembling a corolla of 4 petals — 4.
3b. Flowers in open flattened clusters, without petal-like involucre (shrubs 1-4 m. high; late spring) — 5.
4a. Herbaceous, 3 dm. high or less (flowers in late spring) Dwarf Dogwood, Cornus canadensis.
4b. Tall shrub or tree (flowers in late spring) Flowering Dogwood, Cornus florida.
5a. Leaves distinctly pubescent beneath with woolly or spreading hairs — 6.
5b. Leaves smooth beneath, or pubescent with short appressed hairs — 9.
6a. Leaves rough above; fruit white Dogwood, Cornus asperifolia.
6b. Leaves smooth or finely soft-hairy above — 7.
7a. Leaves at least twice as long as wide; branches brownish or purplish — 8.  
7b. Leaves less than twice as long as wide; branches greenish; fruit blue Dogwood, Cornus circinata.
8a. Branches purplish; fruit blue Dogwood, Cornus amomum.
8b. Branches brownish; fruit white Dogwood, Cornus baileyi.
9a. Branches bright red or reddish-purple Dogwood, Cornus stolonifera.
9b. Branches grayish Dogwood, Cornus paniculata.


ERICACEAE, the Heath Family

Herbs or shrubs, frequently with evergreen leaves; sepals 4-5; corolla regular, with 4-5 petals; stamens as many or twice as many; ovary 3-10-celled, with 1 style.

1a. Plants without green color; leafless or with scale leaves only — 2.
1b. Plants with green leaves — 4.
2a. Flowers solitary (1-2 dm. high; summer) Indian Pipe, Monotropa uniflora.
2b. Flowers in clusters — 3.
3a. Petals united into a bell-shape corolla (3-9 dm. high; summer) Pine Drops, Pterospora andromedea.
3b. Petals all separate (1-3 dm. high; summer) Beech Drops, Monotropa hypopitys.
4a. Leaves all basal; herbaceous plants with terminal racemes (1-4 dm. high; summer) (Shin-leaf) — 5.
4b. Stem-leaves present — 12.
5a. Style straight — 6.
5b. Style bent near the apex — 8.
6a. Racemes one-sided, the flowers all turned in one direction (flowers white or greenish-white) — 7.
6b. Raceme regular, the flowers not all pointing in the same direction (flowers white or pink) Shin-leaf, Pyrola minor.
7a. Flowers numerous in each raceme Shin-leaf, Pyrola secunda.
7b. Flowers only 3-7 in each raceme Shin-leaf, Pyrola seconda var. obtusata.
8a. Flowers pink or purple — 9.
8b. Flowers white or greenish — 10.
9a. Leaves cordate at base Shin-leaf, Pyrola asarifolia.
9b. Leaves rounded at base, not cordate Shin-leaf, Pyrola asarifolia var. incarnata.
10a. Leaves shining on the upper side; sepals one-third as long as the petals Shin-leaf, Pyrola americana.
10b. Leaves dull on the upper side; sepals one-fourth as long as the petals, or a little shorter — 11.
11a. Leaf-blades mostly shorter than their petioles, thick and firm Shin-leaf, Pyrola chlorantha.
11b. Leaf-blades thin, usually longer than their petioles Shin-leaf, Pyrola elliptica.
12a. Petals nearly or quite separate from each other — 13.
12b. Petals united into a gamopetalous corolla, the tube of which is as long as or longer than the lobes — 18.
13a. Leaves opposite or whorled; stems herbaceous or nearly so (summer) — 14.
13b. Leaves alternate; stems shrubby (early summer) — 16.
14a. Flowers solitary; leaves broadly ovate to nearly circular (1 dm. high; flower white) One-flowered Wintergreen, Moneses uniflora.
14b. Flowers in clusters; leaves narrow (stems trailing, 1-3 dm. high; flowers white or pinkish) — 15.
15a. Leaves broadest above the middle, green Prince's Pine, Chimaphila umbellata.
15b. Leaves broadest below the middle, spotted with white Spotted Wintergreen, Chimaphila maculata.
16a. Leaves 2-5 cm. long, densely woolly beneath (5-10 dm. high; flowers white) Labrador Tea, Ledum groenlandicum.
16b. Leaves 1-2 cm. long, pale beneath but not wholly (creeping; flowers pink) (Cranberry) — 17.
17a. Leaves acute Cranberry, Vaccinium oxycoccos.
17b. Leaves obtuse Cranberry, Vaccinium macrocarpon.
18a. Leaves opposite or whorled; corolla saucer-shape (shrubs 3-8 dm. high; flowers purple, summer) — 19.
18b. Leaves alternate; corolla bell-shape or salver-form — 20.
19a. Branches and twigs cylindrical, not angled Sheep Laurel, Kalmia angustifolia.
19b. Branches and twigs with 2 sharp angles Swamp Laurel, Kalmia polifolia.
20a. Plants prostrate, or with a few ascending branches only (flowers white or pink) — 21.
20b. Plants erect or ascending — 23.
21a. Flowers 10-20 mm. long, very fragrant (early spring) Trailing Arbutus, Epigaea repens.
21b. Flowers 4-5 mm. long (late spring) — 22.
22a. Leaves spatulate, broadest beyond the middle Bearberry, Arctostaphylos uva-ursi.
22b. Leaves oval, broadest at the middle Snowberry, Chiogenes hispidula.
23a. Leaves linear, white beneath, their margins strongly revolute (shrub 3-8 dm. high; flowers white, late spring) Bog Rosemary, Andromeda glaucophylla.
23b. Leaves oblong, scurfy beneath with rusty scales (bog shrub 4-10 dm. high; flowers white, in spring) Leatherleaf, Chamaedaphne calyculata.
23c. Leaves smooth, pubescent, or resinous beneath, but not scurfy nor white — 24.
24a. Low shrubs 10-15 cm. high, erect from a creeping rootstock; leaves with the taste of wintergreen (flowers white or pink, summer) Wintergreen, Gaultheria procumbens.
24b. Bushy shrubs 3-8 dm. high; leaves dotted beneath with yellowish resinous dots; ovary 10-celled (flowers greenish-pink, spring) Huckleberry, Gaylussacia baccata.
24c. Shrubs 1 dm. to 3 m. high; leaves not resinous-dotted beneath; ovary 5-celled (flowers white or greenish-pink, spring or early summer) — 25.
25a. Corolla bell-shape, the stamens projecting beyond it (5-15 dm. high) Deerberry, Vaccinium stamineum.
25b. Corolla cylindrical or urn-shape, the stamens not projecting — 26.
26a. Filaments hairy (Blueberry) — 27.
26b. Filaments glabrous (Bilberry) — 32.
27a. Low bushy shrubs, usually less than 5 dm. and never more than 1 m. high — 28.
27b. Tall erect shrubs, 1-4 m. high — 31.
28a. Foliage pubescent Blueberry, Vaccinium canadense.
28b. Foliage glabrous — 29.
29a. Leaves pale-green and glaucous, entire or nearly so Blueberry, Vaccinium vacillans.
29b. Leaves bright-green, distinctly serrulate — 30.
30a. Fruit blue Blueberry, Vaccinium pennsylvanicum.
30b. Fruit black Blueberry, Vaccinium pennsylvanicum var. nigrum.
31a. Leaves downy beneath; fruit black Blueberry, Vaccinium atrococcum.
31b. Leaves smooth or minutely pubescent beneath; fruit blue Blueberry, Vaccinium corymbosum.
32a. Full-grown leaves less than 2.5 cm. long; low much-branched shrubs, mostly less than 5 dm. high — 33.
32b. Full-grown leaves more than 2.5 cm. long; shrubs usually a meter high or more — 34.
33a. Leaves entire; petals usually 4. Bilberry, Vaccinium uliginosum.
33b. Leaves finely serrulate; petals 5 Bilberry, Vaccinium caespitosum.
34a. Leaves serrulate, green beneath, acute; corolla globular Bilberry, Vaccinium membranaceum.
34b. Leaves entire, pale beneath, obtuse; corolla ovoid Bilberry, Vaccinium ovalifolium.