Emily Johnson
Earthstars are a type of fungus belonging to the group Gasteromycetes, or stomach fungi. They are characterised by their star-like appearance, with a roundish ball at the centre, and are found in open woods, usually among leaf litter in deciduous woodland. Earthstars are not considered poisonous, but they are not known to taste good. They have been used in traditional medicines in Chinese and Native American cultures. The spores of the earthstar are dispersed when raindrops fall on the delicate skin of the spore bag, and the rays of the earthstar open and close in response to humidity.
| Characteristics | Values |
|---|---|
| Scientific name | Astraeus hygrometricus |
| Common names | "Hygrometer earthstar", "hygroscopic earthstar", "barometer earthstar", "water-measure earthstar", "false earthstar", "water-measurer" |
| Appearance | Roundish ball in the center of starlike rays |
| Size | 0.75-2 inches across for smaller species, up to 4.75 inches for larger ones |
| Habitat | Grows on the ground in open woods, primarily under hardwood and conifer trees, in leaf litter and humus-rich soil |
| Edibility | Not poisonous, but don't taste good |
| Spore sac | Initially solid, but becomes a mass of powdery spores as it matures; releases spores through a peristome or pore at the top when raindrops hit it |
| Rays | Irregularly cracked surface; spread outwards and downwards, forming a star-like pattern; close when dry |
| Spore color | Reddish-brown |
| Spore shape | Round, covered in small warts |
| Spore size | 7.5-11 micrometers in diameter |
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What You'll Learn
Earthstars are a type of fungus
The inner layer of the peridium, or skin, remains closed, enclosing the spore-filled sac. The sac contains the gleba, which is composed of microscopic elements such as unbranched threads, spore-bearing cells, and the spores themselves. The spores are released through a peristome, a small, fringed opening at the top of the spore sac. When dry, the rays of the earthstar curl up, but they can be reopened by adding water.
Earthstars are found in open woods, primarily under hardwood and conifer trees, and they favour leaf litter and humus-rich soil. They can also be found in dry forests and desert-like environments, and they are known to grow in sandy soils. Earthstars are saprobic fungi, deriving their nutrients from decomposing organic matter.
The collared earthstar, or Geastrum triplex, is the largest member of the Geastrum genus in North America. It is commonly known as the saucered earthstar or triple earthstar, and it was first described scientifically by German botanist Franz Wilhelm Junghuhn in 1840. The immature fruit body is spherical and partially or completely buried in the ground. As it matures, the outer layer of tissue splits, forming the pointed rays that characterise the earthstar.
Another notable species is Astraeus hygrometricus, commonly known as the false earthstar due to its resemblance to the true earthstars of the Geastrum genus. A. hygrometricus is hygroscopic, meaning it can open and close its rays in response to changes in humidity. It was selected as the "Mushroom of the Year" in 2005 by the German Mycological Society.
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They are also known as 'fallen stars'
Earthstars are a type of fungus that belongs to the family Astraceae, which is related to the more familiar mushrooms. One of the most distinctive features of earthstars is their unique shape, which resembles a star-like structure that has fallen to the ground, earning them the nickname "fallen stars." This distinctive shape is a result of the way the earthstar's fruit body develops and emerges from the soil. The fruit body starts as a spherical structure called a sporocarp, which is enclosed in a protective membrane. As the earthstar matures, the sporocarp pushes up against the membrane, causing it to rupture and creating the appearance of a star-shaped structure emerging from the earth, resembling a star that has fallen from the night sky.
The "fallen star" nickname is also a reference to the earthstar's ability to disperse its spores in a unique manner. When the earthstar is mature, the arms of the star-like structure will spread outwards, exposing the spore-bearing surface. This surface is covered in tiny spores, which are then dispersed by the wind or by falling raindrops. The spores of the earthstar are known for their ability to remain viable for long periods, sometimes even surviving for decades, waiting for the right conditions to germinate and grow into new earthstars.
The "fallen star" moniker not only captures the earthstar's distinctive appearance but also hints at their mysterious and almost magical nature. Earthstars often grow in hidden or secluded places, such as in forests or among leaf litter, and their sudden appearance can be quite surprising and enchanting, like discovering a fallen star hidden among the earth's secrets. Their ability to disperse spores over long distances and their worldwide distribution also add to the allure, as if these "fallen stars" have the power to travel and spread their magic across the globe.
In some cultures and folklore, earthstars have been associated with magical properties and have been used in various traditional practices. For example, in some European folk beliefs, earthstars were thought to possess protective powers and were used in charms and amulets to ward off evil spirits and bring good luck. In other traditions, earthstars may be associated with wishes and dreams, with people making wishes upon discovering these "fallen stars," believing that their dreams could be granted or that their wishes would rise up to the stars above.
The "fallen stars" nickname is a beautiful and poetic way to describe these unique fungi, capturing their otherworldly appearance, their mysterious nature, and the sense of wonder they evoke in those who discover them. It is a name that reflects the earthstar's ability to capture the imagination and remind us of the beauty and magic that can be found even in the smallest and most hidden places of the natural world. So, the next time you stumble upon an earthstar, take a moment to appreciate its beauty and the wonder of a fallen star gracing the earth.
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They are not edible
Earthstars are a group of fungi called Gasteromycetes, or "stomach fungi". They are characterised by their star-like appearance, with a roundish ball at the centre, and they grow on the ground in open woods.
Although earthstars are not poisonous, they are not edible. They have a pungent, earthy odour and an oily, moss-like smell. They are used in traditional medicines in Chinese and Native American cultures. However, their taste is not pleasant.
The rounded earthstar, also known as the star of the land or sessile earthstar, is one of the most widespread earthstar species in North America. It is characterised by its distinct circular ridge or depression surrounding the central pore sac. This species typically measures 0.75-2 inches across when fully expanded.
The collared earthstar is the largest member of the Geastrum genus in North America. It is commonly known as the saucered earthstar and triple earthstar. This species is extremely widespread in North America and can be found in England, Wales, Northern Ireland, and central Scotland. It measures 2-4 inches across when fully expanded.
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They are found in the UK, Europe, and North America
Earthstars are a group of fungi called Gasteromycetes, or "stomach fungi". They are characterised by their star-like appearance, with a roundish ball in the centre and starlike rays. They are found on the ground in open woods, primarily under hardwood and conifer trees, and are especially common in leaf litter in deciduous woodland. They are also found in scrubland, along roadside hedgerows, and on sand dunes. Earthstars can survive in dry forests and desert-like environments, and can grow in nutrient-poor, sandy, or loamy soils.
The collared earthstar (Geastrum triplex) is the most common species in the UK, particularly in England, Wales, Northern Ireland, and central Scotland. It is also the largest member of the Geastrum genus in North America, where it is extremely widespread. Other common species in North America include the rounded earthstar, one of the most widespread species on the continent, and Geastrum saccatum, which is commonly found on the west coast.
The Astraeus genus, which includes Astraeus hygrometricus, was previously thought to have a cosmopolitan distribution, but is now thought to be restricted to Southern Europe, with Astraeus species common in temperate and tropical regions. Astraeus hygrometricus is found in France and Turkey, while North American populations have been divided into A. pteridis, A. morganii, and A. smithii.
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They are used in traditional Chinese and Native American medicines
Earthstars are mushrooms that grow on the ground in open woods. They are characterised by a roundish ball in the centre, which contains spores, and starlike rays. The immature fruit bodies of earthstars are spherical, resembling puffballs with pointed beaks. As the fungus matures, the outer layer of tissue splits into four to eight pointed segments that spread outwards and downwards, exposing the spherical inner spore sac.
Earthstars are used in traditional Chinese and Native American medicines. The species Geastrum triplex, commonly known as the collared earthstar, the saucered earthstar, or the triple earthstar, is used in traditional medicines of native North America and China. Fruit bodies have been chemically analysed to determine their lipid content, and various chemical derivatives of the fungal sterol ergosterol have been identified.
In traditional Chinese medicine, several herbs have been used in Western medicine, such as the ginseng decoction used to invigorate "qi" and prevent prostration. This can be prescribed in hemorrhagic or cardiogenic shock. Another example is sweet wormwood, which was popularised in the West after Tu Youyou, a pharmacologist trained in TCM, was awarded the 2015 Nobel Prize in Physiology or Medicine for her work on a novel therapy against malaria.
Native American traditional medicine, on the other hand, has been influenced by the cultural and spiritual beliefs of various tribes. It often involves the use of natural remedies, including plants, herbs, and mushrooms, like the earthstar.
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Frequently asked questions
Earthstars are a group of fungi that are commonly known as "stomach fungi". They are characterised by their roundish ball shape, which sits in the centre of starlike rays. They are also referred to as "false earthstars" due to their resemblance to the true earthstars of genus Geastrum.
Earthstars grow on the ground in open woods, primarily under hardwood and conifer trees. They are often found in leaf litter and humus-rich soil, but can also survive in harsh conditions such as dry forests and desert-like environments.
Earthstars start out as small, roundish balls with pointed tips. As they mature, the outer skin peels back and creates 4-10 arms, which are triangle-shaped and buff to yellow-brown in colour. The inner spore sac is smooth and can range from tan to brown or purplish.
