Trees and woody shrubs of the genus Juniperus form
pure or nearly pure forests over extensive areas of northern
Africa, Mediterranean Europe, the Near East, central Asia, the
Indian subcontinent, and western China. They typically occur
in arid regions where growth is slow. The future health and existence
of many juniper forests is threatened by excessive human use,
grazing by domestic livestock, insects, and diseases.
One of the major disease agents of Old World junipers and
other Cupressaceae is the juniper dwarf mistletoe, Arceuthobium
oxycedri (DC.) M. Bieb. (Figure
1). Arceuthobium oxycedri is the type species of the
genus and one of three Old World dwarf mistletoes that parasitize
Juniperus spp. and other Cupressaceae (Hawksworth and
Wiens 1976, 1996). Arceuthobium oxycedri also has the
most extensive geographic distribution of the 42 recognized species
of Arceuthobium. Its range extends over 100º of longitude
or about 10,000 km from Spain and Morocco to western China.
In their updated monograph on Arceuthobium, Hawksworth
and Wiens (1996) describe their frustrations in summarizing available
records for the hosts and distribution of A. oxycedri. The
labels on many early collections are scarcely legible and in
unfamiliar languages. The political geography of Europe, northern
Africa, the Near East and central Asia has changed significantly,
resulting in changes in national borders and place names, since
A. oxycedri was first described in 1819.
Therefore, many collection sites are difficult, if not impossible,
to locate on present day maps. In addition, new information on
relationships in Juniperus has led to taxonomic revisions.
Consequently, the Hawksworth and Wiens (1996) summary of this
important Old World mistletoe is much outdated.
We review here information on the hosts and geographic distribution
of A. oxycedri based on literature, collections, and new
species definitions for the junipers. Hosts and geographic information
are organized by region:
We plan to update this information periodically and welcome
additional information from colleagues knowledgeable of the distribution
and hosts of Arceuthobium oxycedri for inclusion in future
versions of this paper.