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. It can be an invasive weed.The common hawthorn is a shrub or small tree 5–14 metres (15 to 45 feet) tall, with a dense crown. The bark is dull brown with vertical orange cracks. The younger stems bear sharp thorns, approximately 12.5mm (half an inch) long. The leaves are 20 to 40mm (1 to 1½ inches) 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 hermaphrodete flowers are produced in late spring (May to early June in its native area) in corymbs of 5-25 together; each flower is about 10mm 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 10mm long, berry-like, but structurally a pome containing a single seed.Crataegus monogyna is one of the most common species used as the “hawthorn” of traditional herbalins. The plant parts used are usually sprigs with both leaves and flowers, or alternatively the fruit (“berries”). Hawthorne has been investigated by evidence based medicine for treating cardiac insufficiency. Crataegus monogyna is a source of antioxitand phytochemicals, especially extracts of hawthorn leaves with flowers.