Aseroë rubra is a Basidiomycota fungus belonging to the Phallaceae family that is characterized mainly by its anemone or starfish shape when mature, as well as by its strong odor of excrement. When it has not yet matured, it is shaped like a rounded egg and about 3 centimeters in diameter.
This mushroom, which is called the star mushroom, is naturally distributed in Australia, Tasmania, as well as some islands in the Pacific, where it is quite common. It prefers temperate zones, where it grows in acidic soils and on decaying plant material or grass.
Aseroë rubra.Taken and edited from: This image was created by user Liz Popich (Lizzie) at Mushroom Observer, a source for mycological images.You can contact this user here.English - español - français - italiano - македонски - português - + / -.
It has an unpleasant and characteristic odor, like other fungi of the Phallaceae family, which it uses to attract flies, beetles and other insects that will help it disperse its spores.
characteristics
The immature fruiting body has a rounded egg shape and measures up to 3 centimeters in diameter, this is attached to the substrate by means of numerous root-like structures known as rhizomorphs. Its coloration is whitish, pink or pale brown.
When the fruiting body matures, it emerges from the "egg" and leaves a sac or cup-shaped volva surrounding the stem. This volva is formed from the remains of the veil and is generally partially or totally uncovered from the substrate.
The mature fruiting body, or carpophorus, consists of a stem or foot about 9 cm high by 3 cm in diameter, whitish to brown in color, from which the birmous arms or tentacles emerge.
The number of arms can vary between six and ten; they are united initially but later they are separated almost totally. The approximate size of each arm is 3.5 cm and its coloration is red. Above the arms, the gleba disk (fertile part of the fungus) is observed, which shows a dark mass with a sticky consistency.
The fungi of this family lack a hymenium, the reproductive structure is known by the name of gleba, which in this species appears as a gelatinous, dark and smelly mass located on the upper surface of the carpophor and between the arms in its basal portion..
The spores are formed in this gleba and have an elongated elliptical shape, with a size of 3 to 7 µm by 1.5 to 2.5 µm, they are inamyloid and when they are treated with KOH they are hyaline in appearance.
Habitat and distribution
Aseroë rubra lives in acid soils with abundant decomposing plant remains in temperate zones. It can also be found in grasslands and evergreen and semi-evergreen wooded areas.
The species is apparently native to Australia and Tasmania, where it is fairly common, but it also inhabits numerous islands in the Pacific, including Hawaii, where it is established on at least three of the archipelago's islands.
It is currently widely distributed worldwide, due, according to some researchers, to the fact that it has been accidentally introduced by man in new localities through imported soils for gardening from Australia, as well as associated with other ornamental plants from this same locality..
Among these new localities is England, where the fungus was found for the first time in 1828. There are also records of the species in the United States (California).
However, it has also been found in localities where this explanation is not convincing or feasible, due to the absence of human settlements, as is the case of some uninhabited islands in the Pacific, or in continental areas far from human settlements, such as South Africa or in India.
Taxonomy
Aseroë rubra is a Basidiomycota fungus belonging to the class Agaricomycetes, order Phallales and to the family Phallaceae. This family harbors fungi with foul-smelling fruiting bodies and phallus-shaped (hence the name of the order and the family).
The genus Aseroë was described by the French botanist Jacques Labillardière in 1800, using the Aseroë rubra species as the type species, described simultaneously with the genus and using material from South Tasmania as a base.
It was initially considered a monospecific genus until, almost 90 years later, Fischer describes a new species, Aseroë arachnoidea. Subsequently, several species were described that, after a careful review carried out in 1980, these new species were considered invalid and synonymy of one of the two previous ones.
The genus currently has at least three additional species, including Aseroë floriformis, discovered in Brazil in 2005. Some mycologists taxonomically place this genus in another family, called Clathraceae, and not in the Phallaceae family.
There is at least one variety of Aseroë rubra, named A. rubra var. zeylanica which was recently described, and differs from other specimens mainly by its color and size.
Aseroë rubra. Taken and edited from: Mike Young.
Reproduction
Basidiomycota fungi are characterized by a short-lived diploid phase just before spore formation, and a long-lasting haploid phase. The species of the Phallaceae family lack a hymenium, the spores will form in a structure called gleba that constitutes the fertile part of the fungus.
This spore-laden gleba gives off a foul odor, similar to faeces or decomposing matter that attracts flies, beetles and other insects. Thus, the insects will serve as a vehicle for the dispersal of the spores.
On the one hand, some spores will adhere to the legs or body of the insect. Another form of dispersal is when the insect consumes the gleba, with the spores included, and then releases the latter with the feces. The spores can thus move to new locations.
The relationship between these insects and fungi is comparable to that between flowering plants and bees.
Nutrition
Aseroë rubra is a saprophytic species. Saprophytic species are those that feed on decomposing organic matter. Digestion occurs in the external environment by means of enzymes and other substances released by the fungus. Saprophytic species play an important role in the flow of energy in the ecosystem.
In the case of Aseroë rubra, the organic matter from which it obtains its nutrients is decomposing plant material.
References
- Aseroë rubra. On Wikipedia. Recovered from: en.wikipedia, org.
- Stinkhorn. In Encyclopedia of life. Recovered from: eol.org.
- Phallaceae. On Wikipedia. Recovered from: en.wikipedia, org
- IG Baseia & FD Calonge (2005). Aseroë floriformis, a new phalloid with a sunflower-shaped receptacle. Mycotaxon.
- B. Spooner (1994). Aseroë rubra at Oxshott. Mycologist.
- E. Phillips, JL Gillet-Kaufman & M. Smith. (2018). Stinkhorn Mushrooms (Agaromycetes: Phallales: Phallaceae). At University of Florida IFAS Extension. Recovered from ufl.edu.