''Cronartium'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

rust fungi Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales (previously known as Uredinales). An estimated 168 rust genera and approximately 7,000 species, more than half of which belong to the genus ''Puccinia'', are currently a ...

in the family Cronartiaceae. They are

heteroecious A heteroecious parasite is one that requires at least two hosts. The ''primary host'' is the host in which the parasite spends its adult life; the other is the ''secondary host''. Both hosts are required for the parasite to complete its life cycle ...

rusts with two alternating hosts, typically a

pine A pine is any conifer tree or shrub in the genus ''Pinus'' () of the family Pinaceae. ''Pinus'' is the sole genus in the subfamily Pinoideae. The World Flora Online created by the Royal Botanic Gardens, Kew and Missouri Botanical Garden accep ...

and a

flowering plant Flowering plants are plants that bear flowers and fruits, and form the clade Angiospermae (), commonly called angiosperms. The term "angiosperm" is derived from the Greek words ('container, vessel') and ('seed'), and refers to those plants th ...

, and up to five spore stages. Many of the species are plant

disease A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...

s of major economic importance, causing significant damage. ;Species, hosts and natural distribution *'' Cronartium appalachianum'': ''

Pinus virginiana ''Pinus virginiana'', the Virginia pine, scrub pine, Jersey pine, Possum pine, is a medium-sized tree, often found on poorer soils from Long Island in southern New York south through the Appalachian Mountains to western Tennessee and Alabama. The ...

'',

Santalaceae The Santalaceae, sandalwoods, are a widely distributed family of flowering plants (including small trees, shrubs, perennial herbs, and epiphytic climbersHewson & George t al.br>''Santalaceae'' taxonomy, 1984, pp. 191-194.) which, like other membe ...

. Eastern

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. *''

Cronartium arizonicum ''Cronartium'' is a genus of rust fungi in the family Cronartiaceae. They are heteroecious rusts with two alternating hosts, typically a pine and a flowering plant, and up to five spore stages. Many of the species are plant diseases of major ec ...

'': ''

Pinus ponderosa ''Pinus ponderosa'', commonly known as the ponderosa pine, bull pine, blackjack pine, western yellow-pine, or filipinus pine is a very large pine tree species of variable habitat native to mountainous regions of western North America. It is the ...

'' and related pines,

Scrophulariaceae The Scrophulariaceae are a family of flowering plants, commonly known as the figwort family. The plants are annual and perennial herbs, as well as shrubs. Flowers have bilateral (zygomorphic) or rarely radial (actinomorphic) symmetry. The Scr ...

. Western North America. *'' Cronartium comandrae'': ''Pinus'' subgenus ''Pinus'', Santalaceae. North America. *'' Cronartium comptoniae'': ''Pinus'' subgenus ''Pinus'',

Myricaceae The Myricaceae are a small family of dicotyledonous shrubs and small trees in the order Fagales. There are three genera in the family, although some botanists separate many species from ''Myrica'' into a fourth genus ''Morella''. About 55 speci ...

. North America. *'' Cronartium conigenum'': ''Pinus'' subgenus ''Pinus'',

Fagaceae The Fagaceae are a family of flowering plants that includes beeches, chestnuts and oaks, and comprises eight genera with about 927 species. Fagaceae in temperate regions are mostly deciduous, whereas in the tropics, many species occur as evergre ...

. Southwestern North America. *'' Cronartium flaccidum'': ''Pinus'' subgenus ''Pinus'', several families.

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

. *'' Cronartium occidentale'': ''Strobus'' subgenus ''Strobus'',

Saxifragaceae Saxifragaceae is a family of herbaceous perennial flowering plants, within the core eudicot order Saxifragales. The taxonomy of the family has been greatly revised and the scope much reduced in the era of molecular phylogenetic analysis. The f ...

. Southwestern North America. *''

Cronartium orientale ''Cronartium'' is a genus of rust fungi in the family Cronartiaceae. They are heteroecious rusts with two alternating hosts, typically a pine and a flowering plant, and up to five spore stages. Many of the species are plant diseases of major ec ...

'': ''Pinus'' subgenus ''Pinus''

Quercus An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably '' ...

. Japan. *'' Cronartium quercuum'': ''Pinus'' subgenus ''Pinus'',

. North America, Asia. *''

Cronartium ribicola ''Cronartium ribicola'' is a species of rust fungus in the family Cronartiaceae that causes the disease white pine blister rust. Other names include: (French), (German), (Spanish). ''Cronartium ribicola'' is native to China, and was subsequ ...

'': ''Pinus'' subgenus ''Strobus'',

Grossulariaceae ''Ribes'' is a genus of about 200 known species of flowering plants, most of them native to the temperate regions of the Northern Hemisphere. The various species are known as currants or gooseberries, and some are cultivated for their edible f ...

. Europe, Asia. *'' Cronartium stalactiforme'': ''Pinus'' subgenus ''Pinus'', Scrophulariaceae. North America. *'' Cronartium strobilinum'': ''Pinus'' subgenus ''Pinus'', Fagaceae. Southeastern North America. Some of the species have been introduced accidentally outside of their natural ranges, notably ''C. ribicola'' into North America, where it is an

invasive species An invasive species otherwise known as an alien is an introduced organism that becomes overpopulated and harms its new environment. Although most introduced species are neutral or beneficial with respect to other species, invasive species ad ...

causing heavy mortality in several pines which have little or no resistance to it.

References and external links

* Millar, C. I. & Kinloch, B. B. (1991). Taxonomy, phylogeny, and coevolution of pines and their stem rusts. pp. 1–38 in: Hiratsuka, Y. et al. (1991). ''Rusts of pine. Proceedings of the IUFRO Rusts of Pine Working Party Conference''. Forestry Canada Information Report NOR-X-317.
Forestry Images: photos of some ''Cronartium'' rusts
Pucciniales Taxa named by Elias Magnus Fries Basidiomycota genera {{Teliomycotina-stub