Prunus L. Prunus (Amygdalus), (L.) Focke. Deciduous

35. Prunus L. View in CoL 1

Shrubs or trees. Leaves simple, usually crenate or serrate, petiolate. Stipules free, narrow, more or less scarious, often deciduous. Flowers 5-merous, solitary or in clusters, umbels, corymbs or racemes. Petals pink or white.

The delimitation of the genus and its subgenera here adopted is that of Rehder. Many authors elevate the subgenera or sections to the rank of genus.

Literature: A. Rehder, Bibliography of Cultivated Trees and Shrubs, 318-350. Jamaica Plain. 1949.

1 Ovary and fruit hairy 2 Leaves broadly ovate to suborbicular, convolute in bud 5. armeniaca 2 Leaves at least twice as long as wide, longitudinally folded in bud 3 Small shrub without spines; hypanthium about twice as long as wide 4. tenella 3 Tree or spiny shrub; hypanthium about as long as wide 4 Leaves 6-9 mm wide; fruit 20-25 mm 3. webbii 4 Leaves 12-40 mm wide; fruit at least 35 mm 5 Petals white or pale pink when expanded; mesocarp coriaceous; endocarp compressed, pitted 2. dulcis 5 Petals usually deep pink throughout anthesis; mesocarp succulent; endocarp ±globose, deeply sulcate 1. persica 1 Ovary and fruit glabrous 6 Flowers in racemes or corymbs 7 Flowers in short corymbs of 3-10 16. mahaleb 7 Flowers in elongated racemes of 12-100 8 Leaves evergreen, coriaceous; fruit ovoid-conical, ±acum ­ inate 9 Racemes usually considerably exceeding the subtending leaf; petioles and young twigs dark red 20. Iusitanica 9 Racemes equalling or slightly exceeding the subtending leaf; petioles and young twigs pale green 21. laurocerasus 8 Leaves deciduous, thin and soft; fruit ±globose 10 Petals 6-9 mm 17. padus 10 Petals 2-5-4 mm 11 Bark aromatic; leaves with at least 15 pairs of inconspicuous lateral veins; fruit purplish-black 18. serotina 11 Bark not aromatic; leaves with 8-11 pairs of very distinct lateral veins; fruit dark red 19. virginiana 6 Flowers solitary, or in clusters or umbels 12Pedicel at least twice as long as ripe fruit 13 Shrub seldom more than 1 m; petals 5-7 mm 13. fruticosa 13 Tree or large shrub; petals 9-15 mm 14 Tree with well-defined trunk; leaves dull above; hypanthium urceolate 14. avium 14 Shrub, or small tree without well-defined trunk; leaves glossy above; hypanthium broadly campanulate 15. cerasus 12Pedicel shorter than ripe fruit, or only slightly longer 15 Petals pink 16 Small tree; leaves 5-15 cm; hypanthium campanulate to pelviform 1. persica 16 Low shrub; leaves 1-3 cm; hypanthium tubular 12. prostrata 15 Petals white, rarely veined with red 17 Leaves entirely glabrous 18 Branches not spiny; fruit yellow 11. cocomilia 18 Branches spiny; fruit bluish-black 19 Bark blackish; leaves dull; flowers mostly solitary 8. spinosa 19 Bark silvery-grey; leaves glossy above; flowers mostly in clusters of 2-3 9. ramburii 17 Leaves hairy, at least on the veins beneath 20 Young twigs dull, usually hairy 21 Bark blackish; fruit 10-15 mm, ±erect 8. spinosa 21 Bark brown; fruit 20 mm or more, pendent 10. domestica

20 Young twigs glossy, glabrous

22 Leaves boldly and irregularly serrate 6. brigantina

22 Leaves regularly crenate, or serrate with inconspicuous teeth directed strongly towards apex 7. cerasifera Subgen. Amygdalus (L.) Focke. Deciduous; leaves longitudinally folded in bud. Shoots with terminal bud. Flowers subsessile, in clusters of 1-3, appearing before the leaves on shoots of the previous year’s growth, each flower-bud flanked by 2 leafbuds. Fruit usually pubescent or tomentose; endocarp sulcate or pitted.