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1 Flowers in elongate racemes of (12-) 20-many flowers; [black-cherries, subgenus Padus] |
1 Flowers solitary, in fascicles, in umbellate or corymbose inflorescences, or in short racemes ( P. mahaleb) of 1-12 flowers. |
..2 Fruit glabrous; ovary glabrous or pubescent initially; flowers and fruit pedicellate, the pedicel > 4 mm long (except…) |
....3 Stones globose, not 2-edged; sepals hairy or not; inflorescences subtended by leafy bracts arising from the same bud as the flowers (except P. pensylvanica, P. susquehanae, and P. pumila); [cherries, subgenera Cerasus and Lithocerasus] |
....3 Stones somewhat to strongly flattened, 2-edged; sepals hairy on the upper surface (except P. domestica, P. insititia, and P. cerasifera); inflorescences without leafy bracts arising from the same bud as the flower; [plums, subgenus Prunus] |
..2 Fruit densely velvety or puberulent; ovary densely velvety or puberulent; flowers and fruits sessile or on pedicel 0-2 mm long. |
......4 Fruit scarlet-red, 0.8-1.5 cm in diameter; twigs densely tomentose; fruit and ovary glabrous or somewhat pubescent (but not velvety); leaves < 5 (-7) cm long; petals white (pink in bud), < 13 mm long; [subgenus Lithocerasus, section Armeniacocerasus] |
......4 Fruit yellow, peach, or orange-colored, > 2 cm in diameter; twigs glabrous; fruit and ovary velvety pubescent; leaves > 5 cm long; petals white or pink, > 11 mm long. |
........5 Leaves 8-15 cm long, > 4× as long as wide, falcate; fruit peach-colored, > 5 cm in diameter; [peach; subgenus Amygdalus, section Persica] |
........5 Leaves 5-10 cm long, 1-1.5× as long as wide, not falcate; fruit yellow to orange, 3-5 cm in diameter; [apricots; subgenus Prunus, section Armeniaca]. |
..........6 Twigs reddish-brown; fruits 3-5 cm in diameter, the flesh sweet when ripe |
..........6 Twigs bright green; fruits 2-3 cm in diameter, the flesh sour and/or bitter when ripe |
1 Leaves evergreen, entire or serrate with few or rather many (but widely spaced) prominent teeth; petioles lacking 2 glands near junction with leaf blade. |
..2 Central axes of racemes (35-) 55-130 mm long; petals 3-5 mm long; drupes 13-17 mm in diameter; [exotic, rarely naturalizing from plantings] |
..2 Central axes of racemes 13-50 mm long; petals 1-1.5 mm long; drupes 8-12 mm in diameter; [collectively native in maritime situations from e. NC southwards to s. FL and west to TX, but also cultivated and escaped inland] |
....3 Pedicels 1-4 mm long; central axes of racemes 13-30 (-43) mm long; flowering Feb-May; leaf blades usually > 2× as long as wide; [more widespread, but not in s. FL] |
....3 Pedicels (2-) 3-6 mm long; central axes of racemes (11-) 20-50 mm long; flowering Nov-Jan; leaf blades usually < 2× as long as wide; [of s. FL] |
1 Leaves deciduous, regularly and rather finely toothed; petioles with 2 glands near the junction with the leaf blade. |
......4 Petals 6-10 mm long (longer than the stamens); hypanthium pubescent within; stone sculptured; [exotic, rarely naturalizing] |
......4 Petals 4-7 mm long; hypanthium glabrous within; stone smooth; [native]. |
........5 Leaf teeth triangular, pointing outward; leaves dull above; sepals conspicuously glandular-eroded on the margin, not persistent on the fruit; colonial, thicket-forming shrub from rhizomes; [montane in our area] |
........5 Leaf teeth curved, appressed; leaves shiny above; sepals entire or slightly glandular-eroded on the margin, persistent on the fruit; small to large tree, not clonal; [collectively widespread]. |
..........6 Leaves mostly 1.5-2× as long as wide, often blunt-tipped (except in shoot leaves); lower leaf surface rather uniformly pubescent, the midrib lacking conspicuous tufts or fringes; branchlets reddish hairy |
..........6 Leaves mostly 2-2.5× as long as wide, slightly acuminate; lower leaf surface glabrous except for (in var. serotina) tufts or fringes along the midrib; branchlets glabrous. |
............ 7 Leaf margins coarsely serrate (ca. 5 teeth per cm); petioles of leaves subtending inflorescences ca. 15 mm long; leaf undersurface glabrous; [Edwards Plateau of c. TX, extending slightly into the TX Coastal Plain] |
............ 7 Leaf margins finely serrate (ca. 7 teeth per cm); leaf undersurface usually with a fringe of reddish hairs along the lower midvein; [widespread in our region] |
1 Plants shrubs, to 1.5 (-3) m tall; [subgenus Lithocerasus; section Microcerasus]. |
..2 Inflorescences of 1-2 flowers; drupes reddish, 10-15 mm long; [exotic, persistent from cultivation] |
..2 Inflorescences of 2-5 flowers; [native]. |
....3 Youngest twigs minutely and densely puberulent (use 10× magnification); leaf blades ca 2.6× as long as wide; plants erect, stones mostly orbicular, (5-) 6-8 (-9) mm long, 5-6 mm wide; leaf apices usually obtuse, sometimes acute or rounded; [plants of acid sandy or rocky upland barrens, savannas, or woodlands] |
....3 Youngest twigs usually glabrous, sometimes sparsely puberulent; leaf blades ca. 3.3-3.7× as long as wide; plants decumbent or erect; stones fusiform, ovoid, or subglobose, 6-9.5 mm long, 4.5-5 mm wide ( P. pumila var. depressa) or 6-7 mm wide ( P. pumila var. pumila); leaf apices short-acuminate, acute, or obtuse; [usually in open, sandy or gravelly habitats]. |
......4 Stems prostrate to decumbent; leaf blades oblanceolate, averaging 3.7× as long as wide; stones ovoid to fusiform, 4.5-5 mm wide; [s. PA northward through New England] |
......4 Stems usually erect-ascending, sometimes decumbent or sprawling; leaf blades elliptic, obovate, or oblanceolate, lengths ca. 2.9-3.3× as long as wide; stones subglobose to ovoid, 5-7 mm wide; [endemic to sandy coastal areas of the Great Lakes; known in our area only from Presque Isle, PA] |
1 Plants trees, well over 3 m tall when mature; [subgenus Cerasus]. |
........5 Leaf serrations single to double, the tips of the serrations acuminate to attenuate; leaf blades strongly acuminate to attenuate-caudate. |
..........6 Leaf serrations attenuate; tree with upright form; leaf apices attenuate-caudate; twigs, petioles, and leaf blades glabrous; [subgenus Cerasus, section Sargentiella] |
..........6 Leaf serrations acuminate; tree with weeping or upright (spreading) form; twigs, petioles, and leaf blades hairy (the blades at least along the veins on the lower surface); [subgenus Cerasus, section Microcalymma] |
............ 7 Petioles 5-10 mm long |
............ 7 Petioles 10-20 mm long. |
............ ..8 Leaf blade base obtuse to rounded; leaf blades < 1.7× as long as wide |
............ ..8 Leaf blade base cuneate; leaf blades > 1.8× as long as wide |
........5 Leaf serrations small and obscure or well-developed but rounded to acute; leaf blades acute to acuminate. |
............ ....9 Petals 4-7.5 mm long; fruit < 1 cm in diameter; [subgenus Cerasus, section Phyllomahaleb]. |
............ ......10 Inflorescence with a central axis, thus nearly or actually racemose; fruit blackish; leaves 1-1.5× as long as wide; [exotic tree] |
............ ......10 Inflorescence umbellate to corymbose, the central axis absent or poorly developed; fruit red; leaves 2-5× as long as wide; [native tree] |
............ ....9 Petals 9-15 mm long; fruit 1.3-2.5 cm in diameter; [subgenus Cerasus, section Eucerasus]. |
............ ........11 Leaves 7-15 cm long, persistently hairy beneath, at least along the midrib and veins; pair of petiolar glands on the petiole near the blade; fruit sweet when ripe |
............ ........11 Leaves 4-8 cm long, glabrous beneath once fully-expanded; pair of petiolar glands on the base of the leaf blade; fruit sour when ripe |
1 Flowers and fruits sessile or the pedicel < 3 mm long; flowers solitary; petals ca. 2 mm long; [endemic in c. FL peninsula] |
1 Flowers and fruits on pedicels 0.5-20 mm long; flowers solitary or 2-5 per inflorescence; petals 3-14 mm long; [collectively widespread] |
..2 Flowers 1-2 (-3) per inflorescence; stone somewhat sculptured; [exotic]; [section Prunus]. |
....3 First-year twigs green, shiny, glabrous; fruits 2-3 cm long, yellow to red when ripe; inflorescence of a solitary flower |
....3 First-year twigs brown to gray, dull, often pubescent; fruits either 3-7 cm or 1-2 cm long, blue-black, yellow, or greenish when ripe; inflorescence of 1-3 flowers. |
......4 Fruits 3-7 cm long, blue-black, yellow, or greenish when ripe; leaves 3-8 cm long; twigs somewhat to not at all thorny |
......4 Fruits 1-2 cm long, blue-black when ripe; leaves 1-3 (-4) cm long; twigs very thorny |
..2 Flowers (3-) 4-6 per inflorescence; stone nearly smooth; [native, though some species also cultivated and/or weedy]; [section Prunocerasus]. |
........5 Leaf teeth gland-tipped (or with a scar where the gland has fallen); sepals with marginal glands (except P. angustifolia); ripe fruit yellow, orange, or red. |
..........6 Leaves 3-6 cm long, often folded longitudinally; sepals lacking marginal glands |
..........6 Leaves (4-) 5-13 cm long, not folded (folded in P. munsoniana and P. rivularis); sepals with marginal glands. |
............ 7 Leaves < 2× as long as wide; petals 10-15 mm long; [w. VA, c. IN, and c. IL northwards] |
............ 7 Leaves > 2× as long as wide; petals 4-7 mm long; [mainly west of the Mississippi River and north of the Ohio River, but scattered southeastwards as both natives and introductions]. |
............ ..8 Leaf teeth triangular, ascending, the gland terminal; flowers opening with the leaves; leaves not folded along the midrib |
............ ..8 Leaf teeth depressed, the gland near the sinus; flowers opening before the leaves |
............ ....9 Leaf blades mostly (6-) 7-10 cm long; calyx lobes as long as the calyx tube; shrub or tree to 10 m tall |
............ ....9 Leaf blades mostly 5-7 cm long; calyx lobes shorter than the calyx tube; shrub to 3 m tall |
........5 Leaf teeth glandless (or if glandular, then sharp-tipped); sepals without marginal glands; ripe fruit yellow, orange red, purple-red, purple, or black. |
............ ......10 Petals 10-15 mm long; leaves 6-10 cm long, acuminate; fruit 2-2.5 cm long, red or yellow. |
............ ........11 Leaves narrowly to broadly cuneate at the base; petiole usually lacking glands near its junction with the leaf blade; sepals glabrous on the lower side |
............ ........11 Leaves broadly rounded at the base; petiole usually with glands near its junction with the leaf blade; sepals pubescent on the lower side |
............ ......10 Petals 4-9 mm long; leaves 2-8 cm long, obtuse, acute, or slightly acuminate; fruit 0.9-1.5 cm long, dark purple, black, yellow, orange, or red. |
............ ..........12 Twigs and pedicels pubescent, often densely so; leaf apices acute to obtuse, rarely rounded; leaf blades mostly < 2× as long as wide; shrubs to 2.5 m tall; [Coastal Plain of e. VA, and northward] |
............ ............ 13 Upper leaf surfaces finely hairy; leaf blades 1.2.5 (-3.6) cm wide, > 2× as long as wide; [KS, w. AR, w. LA, TX, westwards] |
............ ............ 13 Upper leaf surfaces glabrous; leaf blades 2-4 cm wide, < 2× as long as wide; [e. VA, e. MD, DE, e. PA, NJ northwards] |
............ ..........12 Twigs and pedicels usually glabrous, but occasionally pubescent; leaf apices acute, sometimes acuminate; leaf blades mostly > 2× as long as wide; shrubs or small trees, 2-6 m tall; [either inland in the Mountains and Piedmont from nw. NC northward, or Coastal Plain, Piedmont, and Mountains of s. NC, SC, GA, FL, AL, MS, LA, and westward]. |
............ ............ ..14 Plants often suckering and forming thickets, less often single plants, shrubs or less often trees; leaf apices short acuminate (to merely acute); pedicels usually < 10 mm long; [Mountains and Piedmont from nw. NC and e. TN northward] |
............ ............ ..14 Plants usually not suckering, often single plants but sometimes in small colonies, generally trees; leaf apices mostly acute; pedicels usually > 10 mm long; [Coastal Plain, Piedmont, and Mountains of s. NC, SC, GA, FL, AL, MS, LA, and westward] |