Crataegus

The generic epithet, Crataegus, is derived from the Greek kratos "strength" because of the great strength of the wood and akis "sharp", referring to the thorns of some species.[7] The name haw, originally an Old English term for hedge (from the Anglo-Saxon term haguthorn, "a fence with thorns"),[8] also applies to the fruit.[9]

Plant of Crataegus monogyna

Close-up of the flowers of C. monogyna

Crataegus species are shrubs or small trees, mostly growing to 5–15 m (15–50 ft) tall,[9] with small pome fruit and (usually) thorny branches. The most common type of bark is smooth grey in young individuals, developing shallow longitudinal fissures with narrow ridges in older trees. The thorns are small sharp-tipped branches that arise either from other branches or from the trunk, and are typically 1–3 cm (1⁄2–1 in) long (recorded as up to 11.5 cm or 4+1⁄2 in in one case[9]). The leaves grow spirally arranged on long shoots, and in clusters on spur shoots on the branches or twigs. The leaves of most species have lobed or serrated margins and are somewhat variable in shape. The fruit, sometimes known as a "haw", is berry-like but structurally a pome containing from one to five pyrenes that resemble the "stones" of plums, peaches, etc., which are drupaceous fruit in the same subfamily.

The number of species in the genus depends on taxonomic interpretation. Some botanists in the past recognised 1000 or more species,[10] many of which are apomictic microspecies. A reasonable number is estimated to be 200 species.[9] The genus likely first appeared in the Eocene, with the ancestral area likely being Eastern North America and in Europe, which at that time remained closely linked due to the North Atlantic Land Bridge. The earliest known leaves of the genus from the Eocene of North America, with the earliest leaves from Europe being from the Oligocene.[11]

The genus is classified into sections which are further divided into series.[12][13] Series Montaninsulae has not yet been assigned to a section.[13][14][15] The sections are:

• section Brevispinae
• section Crataegus
• section Coccineae
• section Cuneatae
• section Douglasia
• section Hupehensis
• section Macracanthae
• section Sanguineae

Hawthorns provide food and shelter for many species of birds and mammals, and the flowers are important for many nectar-feeding insects. Hawthorns are also used as food plants by the larvae of a large number of Lepidoptera species, such as the small eggar moth, E. lanestris. Haws are important for wildlife in winter, particularly thrushes and waxwings; these birds eat the haws and disperse the seeds in their droppings.

The Scots saying "Ne'er cast a cloot til Mey's oot" conveys a warning not to shed any cloots (clothes) before the summer has fully arrived and the Mayflowers (hawthorn blossoms) are in full bloom.[33][34]

The custom of employing the flowering branches for decorative purposes on 1 May is of very early origin, but since the adoption of the Gregorian calendar in 1752, the tree has rarely been in full bloom in England before the second week of that month. In the Scottish Highlands, the flowers may be seen as late as the middle of June. The hawthorn has been regarded as the emblem of hope, and its branches are stated to have been carried by the ancient Greeks in wedding processions, and to have been used by them to deck the altar of Hymenaios. The supposition that the tree was the source of Jesus's crown of thorns doubtless gave rise to the tradition among the French peasantry (current as late as 1911) that it utters groans and cries on Good Friday, and probably also to the old popular superstition in Great Britain and Ireland that ill luck attended the uprooting of hawthorns. Branches of Glastonbury thorn (C. monogyna 'Biflora',[9] sometimes called C. oxyacantha var. praecox), which flowers both in December and in spring, were formerly highly valued in England, on account of the legend that the tree was originally the staff of Joseph of Arimathea.[35]

Robert Graves, in his book The White Goddess,[5] traces and reinterprets many European legends and myths in which the whitethorn (hawthorn), also called the May-tree, is central.

Hawthorn trees demarcate a garden plot; according to legend, they are strongly associated with the fairies

In Celtic lore, the hawthorn plant was used commonly for inscriptions[36] along with yew and apple. It was once said to heal the broken heart. In Ireland, the red fruit is, or was, called the Johnny MacGorey or Magory.

Serbian folklore that spread across Balkan notes that hawthorn (Serbian глог or glog) is essential to kill vampires, and stakes used for their slaying must be made from the wood of the thorn tree.[37]

In Gaelic folklore, hawthorn (in Scottish Gaelic, sgitheach and in Irish, sceach) 'marks the entrance to the otherworld' and is strongly associated with the fairies.[38] Lore has it that it is very unlucky to cut the tree at any time other than when it is in bloom; however, during this time, it is commonly cut and decorated as a May bush (see Beltane).[39] This warning persists to modern times; it has been questioned by folklorist Bob Curran whether the ill luck of the DeLorean Motor Company was associated with the destruction of a fairy thorn to make way for a production facility.[40]

The superstitious dread of harming hawthorn trees prevalent in the British Isles may also be connected to an old belief that hawthorns, and more especially 'lone thorns' (self-seeded specimens standing in isolation from other trees) originate from lightning or thunderbolts and give protection from lightning strikes.[41]

Hawthorn trees are often found beside clootie wells; at these types of holy wells, they are sometimes known as rag trees, for the strips of cloth which are tied to them as part of healing rituals.[42] 'When all fruit fails, welcome haws' was once a common expression in Ireland.

According to a medieval legend, the Glastonbury thorn, C. monogyna 'Biflora', which flowers twice annually, was supposed to have miraculously grown from a walking stick planted by Joseph of Arimathea at Glastonbury in Somerset, England. The original tree was destroyed in the sixteenth century during the English Reformation, but several cultivars have survived. Since the reign of King James I, it has been a Christmas custom to send a sprig of Glastonbury thorn flowers to the Sovereign, which is used to decorate the royal family's dinner table.[43]

In the Victorian era, the hawthorn represented hope in the language of flowers.[44]

The hawthorn – species unspecified[19] – is the state flower of Missouri. The legislation designating it as such was introduced by Sarah Lucille Turner, one of the first two women to serve in the Missouri House of Representatives.[45]

Although it is commonly stated that hawthorns can be propagated by cutting, this is difficult to achieve with rootless stem pieces. Small plants or suckers are often transplanted from the wild. Seeds require stratification and take one or two years to germinate.[46] Seed germination is improved if the pyrenes that contain the seed are subjected to extensive drying at room temperature, before stratification.[47] Uncommon forms can be grafted onto seedlings of other species.[46]