''Pilobolus crystallinus'', commonly known as the "dung cannon" or "hat thrower", is a species of fungus belonging to the

Mucorales The Mucorales is the largest and best-studied order of zygomycete fungi. Members of this order are sometimes called pin molds. The term mucormycosis is now preferred for infections caused by molds belonging to the order Mucorales. Systematic ...

order. It is unique in that it adheres its

spores In biology, a spore is a unit of sexual (in fungi) or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plant ...

to vegetation, so as to be eaten by grazing animals. It then passes through the animals' digestive systems and grows in their feces. Although these fungi only grow to be tall, they can shoot their

sporangium A sporangium (from Late Latin, ; : sporangia) is an enclosure in which spores are formed. It can be composed of a unicellular organism, single cell or can be multicellular organism, multicellular. Virtually all plants, fungus, fungi, and many ot ...

, containing their

, up to away. Due to an increase of pressure in the

vesicle Vesicle may refer to: ; In cellular biology or chemistry * Vesicle (biology and chemistry), a supramolecular assembly of lipid molecules, like a cell membrane * Synaptic vesicle ; In human embryology * Vesicle (embryology), bulge-like features ...

, the

can accelerate 0–45 mph in the first millimeter of its flight, which corresponds to an acceleration of 20000 g. Using a mucus-like substance found in the

of the fungus, the

can adhere itself onto whatever it lands, thus completing its life cycle. The

basionym In the scientific name of organisms, basionym or basyonym means the original name on which a new name is based; the author citation of the new name should include the authors of the basionym in parentheses. The term "basionym" is used in both botan ...

of this species is ''Hydrogera crystallina'' F.H. Wigg. 1780. The ability of this fungus to cause problems for florists was noted in the scientific literature in 1881:

... this small fungus had proved this season to be an expensive annoyance to florists engaged in winter forcing flowers. Rose-growers especially had found it to interfere seriously with their profits. The injury was caused by the projection of the sporangia which covered the flowers and leaves of the roses as if profusely dusted with black pepper. The flowers were almost unsaleable as the first impression was that the black dots were aphids.

Description

This fungus normally grows beneath the surface – a sensitivity to

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

inhibits radial growth at the

hypha A hypha (; ) is a long, branching, filamentous structure of a fungus, oomycete, or actinobacterium. In most fungi, hyphae are the main mode of vegetative growth, and are collectively called a mycelium. Structure A hypha consists of one o ...

e. According to McVickar (1942), and later amended by Ootaki et al. (1993), the development of ''P. crystallinus'' may be divided into six stages: In stage I, the sporangiophore initially elongates at the apex, but does not rotate. In stage II, the sporangiophore develops a

. In stage III, after the development of the sporangium, there is a temporary cessation of growth. In stage IV, a subsporangial vesicle expands beneath the sporangium. This is followed by stage V, where the spore matures, and the region of hypha directly below the subsporangial vesicle continues elongating. Finally, in stage VI, the subsporangial vesicle bursts and throws the sporangium into the air. Scanning and

transmission electron microscopy Transmission electron microscopy (TEM) is a microscopy technique in which a beam of electrons is transmitted through a specimen to form an image. The specimen is most often an ultrathin section less than 100 nm thick or a suspension on a g ...

has shown that the surface of the

is covered with crystals of two distinct sizes. The larger crystals enclose spines having a central pore.

Host species

''Pilobolus crystallinus'' has been reported to grow on the dung of

cattle Cattle (''Bos taurus'') are large, domesticated, bovid ungulates widely kept as livestock. They are prominent modern members of the subfamily Bovinae and the most widespread species of the genus '' Bos''. Mature female cattle are calle ...

References

External links

BBC Nature
{{Taxonbar, from=Q3456426 Fungi described in 1780 Zygomycota Fungus species