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''Crataegus monogyna'', known as common hawthorn or single-seeded hawthorn, is a species of hawthorn native to Europe, northwest Africa and western Asia. It has been introduced in many other parts of the world where it can be an invasive weed. Other common names include may, mayblossom, maythorn, quickthorn, whitethorn, motherdie, and haw. This species is one of several that have been referred to as ''Crataegus oxyacantha'', a name that has been rejected by the botanical community as too ambiguous. ==Description== The Common Hawthorn is a shrub or small tree 5–14 m tall, with a dense crown. The bark is dull brown with vertical orange cracks. The younger stems bear sharp thorns, 1 to 1.5 cm long. The leaves are 2–4 cm long, obovate and deeply lobed, sometimes almost to the midrib, with the lobes spreading at a wide angle. The upper surface is dark green above and paler underneath. The hermaphrodite flowers are produced in late spring (May to early June in its native area) in corymbs of 5-25 together; each flower is about 1 cm diameter, and has five white petals, numerous red stamens, and a single style; they are moderately fragrant. The flowers are pollinated by midges, bees and other insects and later in the year bear numerous ''haws''. The haw is a small, oval dark red fruit about 1 cm long, berry-like, but structurally a pome containing a single seed. Haws are important for wildlife in winter, particularly thrushes and waxwings; these birds eat the haws and disperse the seeds in their droppings. The Common Hawthorn is distinguished from the related but less widespread Midland Hawthorn (''C. laevigata'') by its more upright growth, the leaves being deeply lobed, with spreading lobes, and in the flowers having just one style, not two or three. However they are inter-fertile and hybrids occur frequently; they are only entirely distinct in their more typical forms. Image:Common hawthorn flowers.jpg|Common Hawthorn flowers Image:Eenstijlige meidoorn (Crataegus monogyna branch).jpg|Common Hawthorn thorns, leaves, and stipules Image:Hawthorn fruit.JPG|Common Hawthorn fruit File:Pink and brown (4627395373).jpg|Close-up 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「crataegus monogyna」の詳細全文を読む スポンサード リンク
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