Crataegus L.

34. Crataegus L. View in CoL 2

Deciduous, usually spiny shrubs or small trees. Leaves simple, lobed or pinnatifid, serrate. Stipules persistent. Flowers in corymbs. Petals obovate, white, rarely pink; stamens 5-25; carpels 1-5, free on the ventral side, walls stony in fruit; styles 1-5; ovules 2. Fruit red, yellow or black, usually with mealy flesh; pyrenes 1-5.

In many species the leaves and stipules are much larger and more deeply cut on non-flowering shoots than on flowering shoots. The characters given in the keys and descriptions are to be interpreted as referring only to the leaves of the flowering shoots.

In regions where the areas of two taxa overlap, hybrids are commonly found. Notes about some of these hybrids are given in the text.

1 Lateral veins of leaves ending only in the apices of the teeth or lobes 2 Leaves obovate to oblong-obovate, simply and acutely serrate above, entire at base; spines 70-100 mm 2. crus-galli 2 Leaves ovate or elliptic-ovate, biserrate; spines 10-30 mm 3 Sepals glandular-serrate; stamens 10 1. intricata 3 Sepals entire; stamens 20 4 Leaves lobed to less than | way to the midrib; petioles 8-15 mm 3. sanguinea 4 Leaves lobed to more than | way to the midrib; petioles 15-35 mm 4. altaica 1 Lateral veins of leaves ending both in the apices of the teeth or lobes and in the sinuses 5Young twigs, leaves, pedicels and hypanthia glabrous or with straight, patent hairs 6 Leaf-lobes serrulate; stipules serrate

7 Fruit light or bright red, crowned by erect or erecto-patent sepals 8 Leaf-lobes strongly acuminate; fruit oblong-cylindrical

9. calycina 8 Leaf-lobes subobtuse; fruit subglobose 10. microphylla 7 Fruit dark red to blackish, crowned by deflexed or patent sepals 9 Style 1; fruit with 1 pyrene 9. calycina 9 Styles 2-3; fruit with 2 pyrenes

10 Corymb 5- to 10-flowered, glabrous; twigs glabrescent

11 Leaves lobed to less than | way to midrib, the lobes obtuse; fruit 8-12 mm, without protuberances at the base 5. laevigata

11 Leaves lobed | way to the midrib, the lobes acute; fruit

12-15 mm, usually with 5 protuberances at the base

6. macrocarpa

10 Corymb 12- to 20-flowered, villous; twigs villous

12 Leaves with 3-5 obtuse or acute lobes; lobes serrulate in upper half only; sepals triangular, acute 7. taurica

12 Leaves with 5-7 acuminate lobes; lobes serrulate almost to the base; sepals lanceolate, long-attenuate 8. ucrainica 6 Leaf-lobes entire or with a few acute teeth; stipules entire 13 Leaf-lobes acute to subobtuse; ripe fruit 6-10 mm, dark or bright red 14. monogyna 13 Leaf-lobes acuminate; ripe fruit 10-14 mm, dark purple to blackish 14 Leaf-lobes with only 1 or 2 teeth at apex; leaves 40

80 mm; main veins curving towards base of leaf

13. ambigua 14 Leaf-lobes unevenly serrate in their apical half; leaves

30-35 mm; main veins straight

15 Corymb villous 11. pallasii

15 Corymb glabrous 12. karadaghensis 5 Young twigs, leaves, pedicels and hypanthia tomentose, lanate or sericeous (rarely twigs lanate and leaves glabrous) 16 Petiole 10-30 mm; leaf-lobes serrate; flowers 10-15 mm in diameter 17 Ripe fruit red and pruinose, with 1 pyrene; twigs pruinose

15. sphaenophylla 17 Ripe fruit blackish, with 4-5 pyrenes; twigs not pruinose 18 Leaves with 3-7 lobes; indumentum arachnoid-lanate;

corymb compound, many-flowered 16. pentagyna 18 Leaves with 7-11 lobes; indumentum tomentose; corymb simple, few-flowered 17. nigra 16 Petiole 2-10 mm; leaf-lobes entire or with 1-3 teeth at apex;

flowers 15-20 mm in diameter 19 Leaves not more than 30 mm; fruit 7-10 mm in diameter 20 Indumentum lanate; styles 1-3 19. heldreichii 20 Indumentum sericeous; styles 5 22. pycnoloba 19 Leaves 30-50 mm; fruit 15-25 mm in diameter 21 Twigs and leaves lanate but soon glabrescent; leaf-lobes broad; fruit dark red 18. schraderana 21 Twigs and leaves persistently hairy; leaf-lobes narrow;

fruit orange-red to yellow

22 Leaves with 3-7 acute, sparsely incise-dentate lobes;

styles 3-5 20. laciniata

22 Leaves with 3(—5) subobtuse, entire lobes; styles 1-2

21. azarolus