Telium, plural telia, are structures produced by

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

as part of the reproductive cycle. They are typically yellow or orange drying to brown or black and are exclusively a mechanism for the release of

teliospore Teliospore (sometimes called teleutospore) is the thick-walled resting spore of some fungi (Rust (fungus), rusts and Smut (fungus), smuts), from which the basidium arises. Development They develop in ''telium, telia'' (sing. ''telium'' or ''telio ...

s which are released by wind or water to infect the alternate

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County * Host Island, in the Wilhelm Archipelago, Antarctica People * ...

in the rust life-cycle. The telial stage provides an overwintering strategy in the life cycle of a

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

heteroecious

fungus A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...

by producing teliospores; this occurs on cedar trees. A primary aecial stage is spent parasitizing a separate host plant which is a precursor in the life cycle of heteroecious fungi. Teliospores are released from the telia in the spring. The

spore In biology, a spore is a unit of sexual reproduction, sexual (in fungi) or asexual reproduction that may be adapted for biological dispersal, dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores fo ...

s can spread many kilometers through the air, however most are spread near the host plant.

Host plants

There are a number of plants that can be infected by the telial stage. Therefore, the telial stage is considered a

pathogen In biology, a pathogen (, "suffering", "passion" and , "producer of"), in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a Germ theory of d ...

to those plants. A few specific plant pathogenic species are listed here with their hosts. # '' Puccinia graminis'' or known commonly as black stem rust. It infects many different cereal crops. # ''

Gymnosporangium juniperi-virginianae ''Gymnosporangium juniperi-virginianae'' is a plant pathogen that causes cedar-apple rust. In virtually any location where apples or crabapples (''Malus'') and eastern red cedar (''Juniperus virginiana'') coexist, cedar apple rust can be a destru ...

''. It infects the eastern red cedar. This is shown to the right. # '' Gymnosporangium sabinae''. It infects pear trees. File:Stem rust close up.jpg, '' Puccinia graminis'' on wheat. File:Gymnosporangium sabinae fg05.JPG, '' Gymnosporangium sabinae'' on a pear tree leaf.

Spore stages

The life cycle of rust fungi can have up to five different spore stages and can get quite complex. These stages are: * Stage 0: Pycniospores * Stage I: Aeciospores * Stage II: Urediniospores * Stage III:

Teliospore Teliospore (sometimes called teleutospore) is the thick-walled resting spore of some fungi (Rust (fungus), rusts and Smut (fungus), smuts), from which the basidium arises. Development They develop in ''telium, telia'' (sing. ''telium'' or ''telio ...

s * Stage IV:

Basidiospore A basidiospore is a reproductive spore produced by basidiomycete fungi, a grouping that includes mushrooms, shelf fungi, rusts, and smuts. Basidiospores typically each contain one haploid Ploidy () is the number of complete sets of chromos ...

s File:Puccina graminis lifecycle.gif, Life Cycle of ''Puccina graminis''

References

Fungal morphology and anatomy Reproduction {{plant-disease-stub