- In the beginning
we have only a few unambiguous references to Crataegus.
- In his White Goddess,
Robert Graves identifies hawthorn as Uath, the May element of the tree
calendar used in Europe in pre-christian times. Hawthorns are thus associated
with the mother goddess in her various guises as maiden, nymph, and crone.
History of Plants (transl. A. Hort 1916) contains vivid, accurate
descriptions of plants, including both hawthorns and medlars. I haven't yet
found out whether Crataegus or Mespilus appear in Dioscorides
Materia medica, or in any medieval texts. However, since these genera
appear in 17th and 18th c. herbals it seems likely that their use originated
much earlier. Medlars (Mespilus) have been cultivated for centuries
and so have a rich cultural heritage associated with them, as documented by
Baird & Thieret (1989).
- Beginning in early medieval
times (and probably earlier) hawthorns were used to construct hedgerows along
property boundaries in England. Because hedgerows provide safe sites for the
establishment of other woody species their floristic richness has been used
a means to date these hedgerows (Hooper 1971; Bradshaw 1971).
- Linnaeus' Genera
Plantarum (1737) revised many genera described by Tournefort (1700),
- including both Mespilus
- Linnaeus' Species
Plantarum (1753) named seven species still recognized as hawthorns,
as well as the medlar.
- Icosandria digynia
include Crataegus coccinea, C. crus-galli, C. tomentosa, C. viridis, C.
indica, C. laevigata (as C. oxyacantha), and C. azarolus,
in addition to several other species now placed in other Maloid
CRATAEGUS foliis obtusis bitrifidis serratis.
The first four of these are all new world species, known to Linnaeus from
the earlier works of Plukenet and Clayton, as well as from collections brought
back to him by his student Kalm.
Icosandria pentagynia include Mespilus germanica and several other
species of Mespilus now placed in other Maloid genera.
MESPILUS inermis, foliis lanceolatis integerrimis suntus tomentosus,
- Continued exploration
of both Asia and North America led to descriptions of numerous new Crataegus
- During the late 18th
and the 19th centuries many new species were described including ones collected
by Lewis and Clark, David Douglas, Thomas Nuttall, and others as the western
part of North America was explored more and more intensively.
1896 and 1910 the number of North American Crataegus species
- Many of these species
were described by C. S. Sargent, director of the Arnold Arboretum. Sargent
eventually expressed himself to a correspondent about his pleasure in travelling
in South America, where no hawthorns grew, but categorically denied that hybridization
could be responsible for the large number of entities being discovered. The
large number of species described during this period, together with the observations
described below, led W. H. Camp (1942) to enunciate what he saw as "the
of species concepts in Crataegus
- This quickly followed
the discovery of polyploidy and other evidence (e.g. widespread male sterility)
of hybridization in the genus (Standish 1916; Longley 1924). To date, however,
hybridization has been studied in detail only in situations involving the
Eurasian diploid species C. monogyna, not only in Europe (Raunkaier
1925; Bradshaw 1971; Byatt 1975; Christensen 1982, 1996) but also in North
America where it has been introduced and hybridizes
with native diploid species (Love & Feigen 1978; Wells & Phipps
1989). Polyploid Crataegus are apomictic and are suspected of being
of hybrid origin, but only apomixis has been studied in any detail, and that
only recently (Campbell et al. 1991). Even so, new species of Crataegus
continue to be described without discussion of whether they merely represent
apomictic genotypes, or in fact comprise populations of different, panmictic
- Rhoda Love
Record of Taxonomic Literature
Directory for Botany
Online- The Internet Hypertextbook
uses of hawthorns
Arboretum - Herbarium
- What is an appropriate
species concept for use in Crataegus?
- Such a species concept
must take into account the potential for hybrids and other variant genotypes
to be perpetuated clonally by means of asexually-produced seed.
- Phylogenetic systematics
of Crataegus and Mespilus.
- What are the phylogenetic
relationships between the sections and series within Crataegus? Do
these in fact represent clades within the genus? Do the two species of Mespilus
form the sister-group of Crataegus?
- What is the origin
of the stamen number variation in the Crataegus?
- What are the phylogenetic
relationships between the North American 10- and 20-stamen forms? How did
the derived stamen number arise? Why, with a single exception, are 10-stamen
hawthorns not found in Eurasia?
- Why are polyploid
Crataegus restricted to triploids and tetraploids?
- What mechanisms control
the success of fertilization in crosses between ploidy levels? How frequently
are unreduced gametes produced, and how often does uniparental reproduction
page is a work in progress, jointly with students in my lab and others.
Please use the mailto link below to send additional information that you would
like to see here, e.g. a description of your own work on hawthorns and (or)
medlars, useful links, recipes, or whatever you think might be useful and would
be thought relevant.