''Pilobolus crystallinus'' var. ''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. Systematics ...

order. It is unique in that it adheres its

spores In biology, a spore is a unit of sexual 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 plants, algae, ...

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, 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) In cell biology, a vesicle is a structure within or outside a cell, consisting of liquid or cytoplasm enclosed by a lipid bilayer. Vesicles form nat ...

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

of the fungus, the sporangium can adhere itself onto whatever it lands, thus completing its life cycle. The basionym 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 the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...

inhibits radial growth at the hyphae. 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 sporangium. 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 sporangium 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, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult ma ...

References

External links

BBC Nature
{{DEFAULTSORT:Pilobolus Crystallinus Fungi described in 1780 Zygomycota