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Key to Rosaceae, Key C: Shrubs and trees with simple leaves

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1 Ovary inferior; fruit indehiscent (pome).

..2 Inflorescence a panicle, of > 25 flowers (6-40 in Pyracantha); leaves leathery, evergreen.

....3 Plants armed with thorns  Pyracantha

....3 Plants unarmed.

......4 Pomes purplish-black, 7-10 mm in diameter, each with 3-5 seeds; leaves mostly 10-30 cm long  Eriobotrya japonica

......4 Pomes orangey yellow, (10-) 20-30 mm in diameter, each with 1-2 seeds; leaves (2-) 4-10 cm long  Rhaphiolepis umbellata

..2 Inflorescence an axillary or terminal raceme, fascicle, cyme, or umbel, of < 20 flowers; leaves herbaceous, deciduous.

Show caption*© Scott Ward ........5 Upper surface of leaves bearing dark glandular trichomes along the midrib (most easily seen with a 10× hand lens); shrubs  Aronia

........5 Upper surface of leaves lacking dark glandular trichomes along the midrib; shrubs and trees.

..........6 Ovary and fruit 10-locular; inflorescence a raceme (rarely a fascicle); pome < 1 cm in diameter  Amelanchier

..........6 Ovary and fruit 5-locular; inflorescence a cyme, umbel, or fascicle (lacking an elongated central axis); pome 0.7-10 cm in diameter.

............ 7 Styles distinct; exocarps (carpels within pericarp) bony and seedlike; trees and shrubs, with thorns  Crataegus

............ 7 Styles usually connate at base; exocarps leather or papery and easily opened to expose seeds; small trees, unarmed, or armed with sharp spur branches.

............ ..8 Pome globose to ovoid, lacking stone cells; anthers yellow to white; styles connate at the base; leaves blunt to acuminate; [apples and crabapples]  Malus

............ ..8 Pome globose or pyriform, with stone cells; anthers reddish; styles distinct; leaves acute to acuminate; [pears]  Pyrus

1 Ovary superior; fruit dehiscent (aggregate of follicles, or capsule) or indehiscent (drupe, aggregate of drupelets, aggregate of achenes).

............ ....9 Leaves opposite; fruit an aggregate of usually 3-5 purple to black drupelets; [tribe Kerrieae]  Rhodotypos scandens

............ ....9 Leaves alternate; fruit various (see below; if an aggregate of drupelets, then with >5 drupelets).

............ ......10 Leaves large, > 10 cm wide, palmately veined, palmately lobed; fruit an aggregate of drupelets; [tribe Rubeae]  Rubacer odoratum

............ ......10 Leaves smaller, < 8 cm wide, pinnately veined, either not lobed or basally pinnately lobed; fruit a drupe, a capsule, an aggregate of follicles, or an aggregate of achenes.

............ ........11 Leaves singly serrate or entire (rarely, as in Prunus americana, irregularly and slightly doubly serrate), not lobed basally.

............ ..........12 Gynoecium of separate carpels; fruit an aggregate of follicles; [tribe Spiraeeae]  Spiraea

............ ..........12 Gynoecium of fused carpels; fruit either a fleshy drupe or a capsule.

............ ............ 13 Ovary 5-angled in ×-section; fruit a 5-angled capsule; leaves obovate, obviously broadest towards the tip; [tribe Osmaronieae]  Exochorda racemosa

............ ............ 13 Ovary circular in ×-section; fruit a fleshy spherical drupe; leaves generally broadest near or below the middle; [tribe Amygdaleae]  Prunus

Show caption*© Alan Weakley ............ ........11 Leaves doubly serrate, also often lobed towards the base.

............ ............ ..14 Corolla yellow; stems arching, green; fruit an aggregate of drupe-like achenes (dry and indehiscent); [tribe Kerrieae]  Kerria japonica

............ ............ ..14 Corolla white to pink or rose; stems not both arching and green; fruit various (see below).

............ ............ ....15 Inflorescence a dense, umbel-like corymb; leaf apices rounded to acute; fruit an aggregate of 5 follicles; [tribe Neillieae]  Physocarpus

............ ............ ....15 Inflorescence a raceme or a leafy panicle; leaf apices acuminate.

............ ............ ......16 Fruit a single follicle; [exotic, planted, and rarely naturalized, as in e. VA]; [tribe Neillieae]  Neillia incisa

............ ............ ......16 Fruit an aggregate of 2-4 drupe-like achenes; [rare native of calcareous habitats in sc. TN, nw. GA, n. AL, and disjunct westward in AR and MO]; [tribe Kerrieae]  Neviusia alabamensis