Gymnosporangium is a genus of heteroecious plant-pathogenic fungi which alternately infect members of the family Cupressaceae, primarily species in the genus Juniperus ( junipers ), and members of the family Rosaceae in the subfamily Maloideae ( apples, pears, quinces, shadbush, hawthorns, rowans and their relatives ).

Although termed cedar or cedarwood oils, the most important oils of this group are produced from distilling wood of a number of different junipers and cypresses ( Juniperus and Cupressus spp., of the family Cupressaceae ), rather than true cedars ( Cedrus spp., of the family Pinaceae ).

In the higher altitudes ( 3, 300 – 6, 300 mi ( 1, 000 – 1, 200 m )) appear pine trees Pinus pinaster and Pinus pinea, as well as Holm ( Quercus ilex ), junipers ( Juniperus oxycedrus ) and jarales Cistus ladanifer.

They typically inhabit scrub forests made up primarily of oaks ( Quercus ilex ), pines ( Pinus gerardiana ), and junipers ( Juniperus macropoda ).

Conifer forests are predominant, chiefly Anatolian black pine ( Pinus nigra ), Cedar of Lebanon ( Cedrus libani ), Taurus fir ( Abies cilicica ), and juniper ( Juniperus foetidissima and J. excelsa ).

Due to its high rainfall ( 900 – 1200 mm ), mild temperatures and high mountains ( Mount Meron's elevation is 1, 000 – 1, 208 metres ), the upper Galilee region contains some unique flora and fauna: prickly juniper ( Juniperus oxycedrus ), Lebanese cedar ( Cedrus libani ), which grows in a small grove on Mount Meron, cyclamens, paeonias and Rhododendron ponticum which sometimes appears on Meron.

Due to the islands ' isolation, for many years Bermuda remained an outpost of 17th-century British civilization, with an economy based on the use of the islands ' Bermuda cedar ( Juniperus bermudiana ) trees for shipbuilding, and Bermudians ' control of the Turks Islands, and their salt trade.

During late spring or early summer, yellow orange or brown, hairlike or ligulate structures called telia grow on the leaves or emerge from bark of woody hosts such as Juniperus species.

* Gymnosporangium juniperi-virginianae ( Cedar-apple rust ); the Juniperus virginiana is the primary ( telial ) host and the apple, pear or hawthorn is the secondary ( aecial ) host. Heteroecious and demicyclic

American beech ( Fagus grandifolia ), shortleaf pine ( Pinus echinata ), pitch pine ( P. rigida ), Virginia pine ( P. uirginiana ), Ozark chinkapin ( Castanea ozarkensis ), eastern redcedar ( Juniperus virginiana ), bluejack oak ( Quercus incana ), southern red oak ( Q. falcata ), blackgum ( Nyssa sylvatica ), and winged elm ( Ulmus alata ) also grow in association with chinkapin oak.

This site is most significant for the occurrence of Dwarf Juniper ( Juniperus communis ) along its ridgeline.

The Cedar Keys are named for the Eastern Red Cedar, Juniperus virginiana, once abundant in the area.

There are also many of the Eastern red cedar ( Juniperus virginiana subsp.

The area lies in the western portions of the Texas Hill Country, a region of limestone outcrops and rolling terrain dotted with areas of live oaks ( Quercus fusiformis ) and Juniper ( Juniperus ashei ) in the form of a woodland or savanna, alternating with a blend of various grasses and other shrubs and cacti.

The crude oils are often yellowish or even darker in colour and some, such as Texas cedarwood oil ( derived primarily from Juniperus ashei and J. deppeana, are quite viscous and deposit crystals on standing.

Junipers are coniferous plants in the genus Juniperus () of the cypress family Cupressaceae.

The section Juniperus is an obvious monophyletic group though.

* Juniperus sect.

** Juniperus sect.

Juniperus subsect.

Juniperus: Cones with 3 separate seeds ; needles with one stomatal band.

**** Juniperus communis subsp.

*** Juniperus conferta-Shore Juniper ( syn.

** Juniperus sect.

Extensive horizontal mesas are capped by sedimentary formations and support woodlands of junipers, pinon, and ponderosa pines, each favoring different elevations.

In junipers ( the primary hosts ) ( see photo ), some species of the fungus form a ball like gall about 2 – 4 cm in diameter which produces a set of orange tentacle-like spore tubes called telial horns.

The fungus does not cause serious damage to junipers, but apple and pear trees can suffer serious loss of fruit production due to the effects of the fungus.

The severity of Cedar-apple rust disease can be managed by removal of basidiospore producing galls from junipers or the application of protective fungicides to junipers.

Underwater archaeology of the caldera basin to the north shows that the area was once densely forested with junipers when it was above sea level.

As that industry died out in the 19th century, however, the junipers rapidly recovered their numbers.

In the 1940s, it was realised that two species of scale insect, Lepidosaphes newsteadi and Carulaspis minima, had accidentally been introduced, and were rapidly killing off the junipers, which had no immunity to their toxicological effect.

A study of mistletoe in junipers concluded that more juniper berries sprout in stands where mistletoe is present, as the mistletoe attracts berry-eating birds which also eat juniper berries.

* The common junipers grow at elevations above the rhododendrons.

* Three species of bilberry are associated with the junipers.

Since juniper prefers a more alkaline soil, it is sometimes possible to locate the margins of the ancient sea from a distance by looking for the distinctive light green color of junipers growing on the more alkaline oceanic dolomite deposits between the island hills.

Here the Ponderosa Pine forest transitions into the high desert, characterized by arid land, junipers, sagebrush, and bitter-brush.

A little higher, junipers are common.

Many junipers ( e. g. J. chinensis, J. virginiana ) have two types of leaves: seedlings and some twigs of older trees have needle-like leaves 5 – 25 mm long ; and the leaves on mature plants are ( mostly ) tiny ( 2 – 4 mm long ), overlapping and scale-like.

The needle-leaves of junipers are hard and sharp, making the juvenile foliage very prickly to handle.

The junipers are divided into several sections, though ( particularly among the scale-leaved species ) which species belong to which sections is still far from clear, with research still on-going.

Sabina: Scale-leaf junipers.

Provisionally, all the other junipers are included here, though they form a paraphyletic group.

Some junipers are susceptible to Gymnosporangium rust disease, and can be a serious problem for those people growing apple trees, the alternate host of the disease.