Hawthorn (Genus Crataegus)

 

Crataegus, commonly called hawthorn or thornapple, is a large genus of
shrubs and trees in the rose family, Rosaceae, native to temperate regions
of the Northern Hemisphere in Europe, Asia and North America. The
white hawthorn (Crataegus punctata) is the state flower of Missouri. The
name hawthorn was originally applied to the species native to northern
Europe, especially the common hawthorn Crataegus monogyna, and the
unmodified name is often so used in Britain and Ireland. However the

name is also applied to the entire genus, and also to the related Asian

genus Rhaphiolepis.

 

They are shrubs or small trees, mostly growing to 5–15 m tall, 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 long (recorded as up to 11.5 cm in one case).

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 serrate margins and are somewhat variable in shape. The fruit,

sometimes known as a "haw", is berry-like, but structurally a pome

containing from 1 to 5 pyrenes that resemble the "stones" of plums,

peaches, etc. which are drupceous fruit in the same subfamily.

 

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. Haws are important for wildlife in winter, particularly
thrushes and waxwings; these birds eat the haws and disperse the seeds in
their droppings.

 

Many species and hybrids are used as ornamental and street trees. The
common hawthorn is extensively used in Europe as a hedge plant. Several
cultivars of the midland hawthorn Crataegus laevigata have been selected
for their pink or red flowers. Hawthorns are among the trees most recom-
mended for water conservation landscapes.

 

The number of species in the genus depends on taxonomic interpretation.
Some botanists in the past recognised a thousand or more species; it is
estimated that a reasonable number is 200 species, but it is not yet clear
how many species should be recognized because a large portion of the
synonymy, especially in North American Crataegus, has not been worked
out. Problems with identification are caused by extensive hybridization
among hawthorns, and by genetic changes in which the characteristics on
an individual tree or population of trees may show greater variation than
exist bwtween known species.

 

Listed in the Atlas of Virginia Flora are six different species of Genus
Crataegus identified as occurring in Facquire County. These species are:

 

1) pear hawthorn (Crataegus calpodendron (Ehrh.) Medik.)
2) cockspur hawthorn (Crataegus crus-galli L.)
3) Crataegus dodgei Ashe
4) Crataegus margarettiae Ashe
5) waxy-fruit hawthorn (Crataegus pruinosa (Wendl. f.) K. Koch)
6) Crataegus pruinosa var. dissona (Sarg.)
7) Crataegus pruinosa var. rugosa (Ashe)
8) one-flowered hawthorn (Crataegus uniflora Muenchh.)

 

However, this figure may not be accepted by all authorities. Some
botantists do not accept Crataegus dodgei and Crataegus margarettiae as
separate species, defining both as synonyms for Crataegus chrysocarpa
Ashe, round-leaved hawthorn. Also, Crataegus pruinosa var. dissona is
now generally separated into a distinct species, Crataegus dissona, north-
ern hawthorn, while Crataegus pruinosa var. rugosa is now generally
defined as a synonym for Crataegus pruinosa var. leiophylla, frosted
hawthorn.

 

With the lack of taxonomic agreement as to what constitutes species of
Crataegus, as well as the hybridization among species, the exact status
of hawthorns in Sky Meadows State Park is uncertain. Currently, two
species may reside within park boundaries, either as distinct species or
hybrids - cockspur hawthorn (Crataegus crus-galli) and dotted hawthorn
(Crataegus puncata). Both are described on subsequent pages.

 

 

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