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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
    3 Plants unarmed.
      4 Pomes purplish-black, 7-10 mm in diameter, each with 3-5 seeds; leaves mostly 10-30 cm long
      4 Pomes orangey yellow, (10-) 20-30 mm in diameter, each with 1-2 seeds; leaves (2-) 4-10 cm long
  2 Inflorescence an axillary or terminal raceme, fascicle, cyme, or umbel, of < 20 flowers; leaves herbaceous, deciduous.
image of plant
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
        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
          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
             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]
               8 Pome globose or pyriform, with stone cells; anthers reddish; styles distinct; leaves acute to acuminate; [pears]
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]
                 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]
                   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]
                       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]
                          13 Ovary circular in ×-section; fruit a fleshy spherical drupe; leaves generally broadest near or below the middle; [tribe Amygdaleae]
image of plant
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]
                            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]
                              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]
                                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]