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Crataegus Key
This group is an extremely large one with over 1,000 names having been applied to the North American forms. There is little agreement as to the differentiation of species and hybrids. For accurate identification, both flowering material and material with ripe fruit must be carefully examined. Leaf descriptions for this genus refer to leaves on branches where flowers or fruit are also present. Wherever possible, specimens should be collected and preserved for future reference. For general information on the genus, see the Crataegus page.
| 1 | Veins of the larger leaves running to the sinuses as well as to the points of the lobes; leaves thick, persistent and remaining green until late in the season; nutlet single | (one-seed hawthorn) Crataegus monogyna |
| Veins of the leaves running only to the apices of the lobes | 2 | |
| 2(1) | Nutlets plane on the inner surface | 4 |
| Nutlets pitted on the inner surface; fruit usually 1 cm or less thick; leaves mostly elliptic, rhombic or ovate; fruit bright red or orange | 3 | |
| 3(2) | Leaves dark or bright green, lustrous above, glabrous, elliptic, rhombic or ovate, sharply serrate except near base, with 4-5 pairs of short acute lateral lobes; young branchlets glabrous (or rarely slightly hairy at first); flowers many, in glabrous corymbs; anthers pink or white; fruit subglobose, bright red and succulent when ripe | (fleshy hawthorn) Crataegus succulent |
| Leaves dull yellow green above, pubescent beneath, often irregularly lobed above middle; young branchlets tomentose; flowers many, in tomentose corymbs; anthers pink (rarely white); fruit oblong, bright red or orange red, with thin sweet, often succulent flesh; nutlets 2-3 deeply pitted on inner surface | (pear hawthorn) Crataegus calpodendron | |
| 4(2) | Leaves mostly obovate, oblong or oblong elliptic, broadest above the middle, thick or firm, fairly uniform in type, with pinnate primary veins | 5 |
| Leaves not prevailingly obovate, oblong or oblong elliptic, broadest at or below middle | 6 | |
| 5(4) | Leaves not lobed, mostly obovate or oblong obovate, sharply serrate except toward the cuneate base, subcoriaceous, rounded or short pointed at apex; leaf veins inconspicuous or only slightly impressed above; petioles short, stout, usually less than one-fourth as long as blade, wing margined nearly to base; flowers many, in glabrous corymbs; anthers pink or pale yellow; fruit inedible, remaining hard and dry, greenish or dull red; nutlets usually 1-2 | (cockspur hawthorn) Crataegus crus-galli |
| Leaves more or less lobed toward apex, more deeply lobed on vegetative shoots, sharply serrate or dentate, veins distinctly impressed above; leaves prevailingly obovate, broadest above middle and gradually narrowed to the short wing-margined petiole; flowers several in pubescent corymbs; anthers red or yellow; fruit subglobose with thick mellow flesh; nutlets 3-5 | (dotted hawthorn) Crataegus punctata | |
| 6(4) | Leaves mostly rhombic or elliptic or rarely oblong ovate in outline, broadest about the middle, wedge shaped or abruptly narrowed at base | 7 |
| Leaves mostly ovate, oblong ovate or deltoid in outline, broadest below or rarely at about the middle | 8 | |
| 7(6) | Leaves with rather uniform sharp spreading lobes, mostly oval to suborbicular, serrate except near base with lower teeth gland tipped; petioles glabrous; inflorescence conspicuously bracteate; flowers in loose villous corymbs; anthers white or pale yellow; fruit hard until late in season, dark red or rarely yellow, not pruinose; nutlets 3-4 | (fireberry hawthorn) Crataegus chrysocarpa |
| Leaves usually with shallow but sharp, or obscure lobes developed only above middle of blade, entire toward the base; leaves oval, rhombic or broadly obovate (usually with 3-4 pairs of small, acute, shallow lobes above middle, or on vegetative shoots with coarser teeth and more deeply lobed) with 3-4 pairs of veins: flowers in compact glabrous corymbs; anthers yellow; fruit subglobose. Dull orange to red, with thin dry flesh: nutlets 2-3; flexuous thorny branchlets usually present | (Dodge hawthorn) Crataegus dodgei | |
| 8(6) | Young leaves roughened above with short appressed hairs; stamens usually 10 or fewer (rarely 20); fruit with a small sessile calyx | 9 |
| Young leaves glabrous or pubescent; stamens 10 or 20; fruit with a large prominent calyx; nutlets usually 3-5 | 11 | |
| 9(8) | Leaves thin, usually acuminate, the points of the lobes often reflexed; fruit usually bright red, succulent | 10 |
| Leaves firm, pointed, the tips of the lobes not reflexed, deeply incised (sometimes halfway to midrib on vegetative shoots), mostly 5-6 cm long, ovate or deltoid, with 4-5 pairs of acuminate lateral lobes, glabrous; flowers in nearly simple glabrous corymbs; anthers rose colored; fruit obovoid or pear shaped, bright red; nutlets 4-5 | (no common name) Crataegus filipes | |
| 10(9) | Flowers 1.3-1.8 cm wide; calyx lobes entire or nearly so; stamens 10 or less; fruit bright red, obovoid (if subglobose, less than 1 cm thick); nutlets 3-5, plane or only slightly ridged on back; leaves mostly ovate, sharply serrate, with usually 5 pairs of broad triangular lateral lobes, thin; flowers in glabrous corymbs; anthers red | (large-seed hawthorn) Crataegus macrosperma |
| Flowers 1.8-2 cm wide; calyx lobes conspicuously glandular serrate; stamens about 20; fruit bright crimson, subglobose; nutlets 3-5 (usually 5); leaves glabrous, thin but firm, bluish green at maturity, with 3-5 pairs of acute lobes; flowers in compound glabrous corymbs; anthers pink | (no common name) Crataegus tortilis | |
| 11(8) | Foliage and inflorescence copiously tomentose, the midribs and petioles appearing thickened; leaves of vegetative shoots mostly truncate or cordate at base, or if rounded, with coarse shallow teeth, variable in shape, mostly ovoid or deltoid, sharply, coarsely serrate, usually with 4-5 pairs of lateral lobes; flowers many, in tomentose corymbs; stamens about 20; anthers small, yellowish or rarely pink, fruit subglobose or rarely obovoid, scarlet or bright crimson, pubescent at least in part; outlets normally 5 | (downy hawthorn) Crataegus molli |
| Foliage and inflorescence glabrous or pubescent; petioles and midribs slender; fruit glabrous; nutlets 3-5 | 12 | |
| 12(11) | Leaves prevailingly ovate (or deltoid), sharply and irregularly serrate, rounded or abruptly narrowed at base, usually with 3-5 pairs of shallow or obscure lobes, glabrous, bluish green, firm at maturity; petioles 1/3 to 2/3 as long as blades; flowers in glabrous corymbs; stamens about 20; anthers pink or rarely creamy white; fruit subglobose, dull crimson or green and dark dotted, pruinose, with a prominent elevated calyx, remaining bard until late in the season; nutlets 4-5 | (frosted hawthorn) Crataegus pruinosa |
| Leaves prevailingly oblong ovate, broadest about the middle, finely and sharply serrate nearly to the rounded base; stamens about 10; fruit soft or mellow when ripe | 13 | |
| 13(12) | Leaves elliptic or oblong ovate, usually narrowed or acute at the base except on vegetative shoots, sharply and deeply serrate, usually with 4-6 pairs of shallow or small acute lateral lobes; fruit obovoid, definitely longer than thick, bright red; nutlets usually 3; anthers pink or red; flowers many in glabrous corymbs | (Holmes hawthorn) Crataegus holmesiana |
| Leaves mostly oblong ovate or oval, rounded (rarely acute) at base, sharply serrate nearly to base, more or less indented with 4-5 pairs of sharp, spreading lateral lobes, on vegetative shoots often ovate and more deeply divided; fruit oblong (only slightly longer than thick), bright red; nutlets 3-5; anthers pink or red; flowers many in slightly villous corymbs | (scarlet hawthorn) Crataegus pedicellata |
Last Revised: Monday July 30 2007
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