Astraeus odoratus is a species of false earthstar

Astraeus (genus)

Astraeus is a genus of fungi in the Diplocystaceae family. The genus, which has a cosmopolitan distribution, contains five species of earthstar mushrooms. They are distinguished by the outer layer of flesh that at maturity splits open in a star-shape manner to reveal a round spore sac...

 in the family Diplocystaceae

Diplocystaceae

Diplocystaceae is a family of fungi in the Boletales order. The family was described by mycologist Hanns Kreisel in 1974....

. Described as a new species in 2004, it was originally found in Thailand growing in sandy or laterite

Laterite

Laterites are soil types rich in iron and aluminium, formed in hot and wet tropical areas. Nearly all laterites are rusty-red because of iron oxides. They develop by intensive and long-lasting weathering of the underlying parent rock...

-rich soil in dry lowland dipterocarp forests. The species is found in Southeast Asia

Southeast Asia

Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...

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Description

Fruit bodies

Sporocarp (fungi)

In fungi, the sporocarp is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne...

 begin as brownish spheres or flattened spheres, partially submerged in the earth. The outer tissue layer, the exoperidium, splits open in a star-like fashion into 3–9 rays. The rays are hygroscopic, spreading out when moist and curling inward when dry. The fully expanded fruit body measures up to 65 millimetres (2.6 in) in diameter. Fresh fruit bodies have an odor similar to moist soil.

The spores are spherical, covered with spines, and measure 7.5–15.2 µm

Micrometre

A micrometer , is by definition 1×10-6 of a meter .In plain English, it means one-millionth of a meter . Its unit symbol in the International System of Units is μm...

. The ornamentation of the spines on the surface is less dense than that of the similar Astraeus hygrometricus

Astraeus hygrometricus

Astraeus hygrometricus, commonly known as the hygroscopic earthstar, the barometer earthstar, or the false earthstar, is a species of fungus in the Diplocystaceae family. Young specimens resemble a puffball when young and unopened...

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Young fruit bodies are collected from the wild and sold in the markets of Thailand

Thailand

Thailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...

; because they cannot be cultivated commercially, they fetch a high price on the market. Thais call the young fruit bodies Hed Pho Hnang orHed Hnang (skinny mushroom); they use the mushroom "cooked in curry or even boiled in water with fish sauce and palm sugar".

Habitat and distribution

Astraeus odoratus it is found in the dry lowland dipterocarp forests of Thailand. The fungus fruits during the rainy season in May and June, in sandy or laterite

Laterite

Laterites are soil types rich in iron and aluminium, formed in hot and wet tropical areas. Nearly all laterites are rusty-red because of iron oxides. They develop by intensive and long-lasting weathering of the underlying parent rock...

-rich soil. It associated with Alder

Alder

Alder is the common name of a genus of flowering plants belonging to the birch family . The genus comprises about 30 species of monoecious trees and shrubs, few reaching large size, distributed throughout the North Temperate Zone and in the Americas along the Andes southwards to...

, Chestnut

Chestnut

Chestnut , some species called chinkapin or chinquapin, is a genus of eight or nine species of deciduous trees and shrubs in the beech family Fagaceae, native to temperate regions of the Northern Hemisphere. The name also refers to the edible nuts they produce.-Species:The chestnut belongs to the...

, Eucalyptus

Eucalyptus

Eucalyptus is a diverse genus of flowering trees in the myrtle family, Myrtaceae. Members of the genus dominate the tree flora of Australia...

and Douglas-fir

Douglas-fir

Douglas-fir is one of the English common names for evergreen coniferous trees of the genus Pseudotsuga in the family Pinaceae. Other common names include Douglas tree, and Oregon pine. There are five species, two in western North America, one in Mexico, and two in eastern Asia...

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In Thailand, it is commonly believed that forest fires stimulate the growth of mushrooms, including A. odoratus, and fires are set intentionally to increase the yield of fruit bodies. Although the mushrooms may be easier to find and collect on the litter

Forest floor

The forest floor, also called detritus, duff and the O horizon, is one of the most distinctive features of a forest ecosystem. It mainly consists of shed vegetative parts, such as leaves, branches, bark, and stems, existing in various stages of decomposition above the soil surface...

-free ground of burnt forest, there is no evidence that burning increases yield, while it does decrease the biodiversity and yield of other edible mushroom-producing fungi.