A fungus is any member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. The Fungi are classified as a kingdom that is separate from plants and animals. The discipline of biology devoted to the study of fungi is known as mycology, which is often regarded as a branch of botany, even though genetic studies have shown that fungi are more closely related to animals than to plants. Fungi reproduce via spores, which are often produced on specialized structures or in fruiting bodies, such as the head of a mushroom. Abundant worldwide, most fungi are inconspicuous to the naked eye because of the small size of their structures, and their cryptic lifestyles in soil, on dead matter, and as symbionts of plants, animals, or other fungi. Fungi perform an essential role in the decomposition of organic matter and have fundamental roles in nutrient cycling and exchange. They have long been used as a direct source of food, such as mushrooms and truffles, as a leavening agent for bread, and in fermentation of various food products, such as wine, beer, and soy sauce. Since the 1940s, fungi have been used for the production of antibiotics, and, more recently, various enzymes produced by fungi are used industrially and in detergents. Fungi are also used as biological agents to control weeds and pests. Many species produce bioactive compounds called mycotoxins, such as alkaloids and polyketides, that are toxic to animals including humans. The fruiting structures of a few species are consumed recreationally or in traditional ceremonies as a source of psychotropic compounds. Fungi can break down manufactured materials and buildings, and become significant pathogens of humans and other animals. Losses of crops due to fungal diseases or food spoilage can have a large impact on human food supplies and local economies. Despite their importance on human affairs, little is known of the true biodiversity of Kingdom Fungi, which has been estimated at around 1.5 million species, with about 5% of these having been formally classified.
Chorioactis is a genus of fungus that contains the single species Chorioactis geaster; the mushroom is commonly known as the devil’s cigar or the Texas star in the United States, while in Japan it is called kirinomitake( キリノミタケ).
This extremely rare mushroom is notable for its unusual appearance and disjunct distribution: it is only found only in select locales in Texas and Japan. The fruit body, which grows on the stumps or dead roots of cedar elms (in Texas) or dead oaks (in Japan), somewhat resembles a dark brown or black cigar before it splits open radially into a starlike arrangement of four to seven leathery rays. The interior surface of the fruit body bears the spore-bearing tissue known as the hymenium, and is colored white to brown, depending on its age. Fruit body opening can be accompanied by a distinct hissing sound and the release of a smoky cloud of spores.
Fruit bodies were first collected in Austin, Texas in 1893, and the species was named Urnula geaster; it was later found in Kyushu in 1937, but the mushroom was not reported again in Japan until 1973. Although the new genus Chorioactis was proposed to accommodate the unique species a few years after its original discovery, it was not until 1968 that it was accepted as a valid genus. Its classification has also been a source of confusion. Historically, Chorioactis was placed in the Sarcosomataceae family of fungi, despite inconsistencies in the microscopic structure of the ascus, the saclike structure in which spores are formed. Phylogenetic analyses of the past decade have clarified the fungus's classification: Chorioactis, along with three other genera, make up the Chorioactidaceae family, a grouping of related fungi formally acknowledged in 2008. In 2009, Japanese researchers reported discovering a form of the fungus missing the sexual stage of its life cycle; this asexual state was named Kumanasamuha geaster.
Mycena flavoalba, commonly known as the ivory bonnet, is a species of inedible mushroom in the Mycenaceae family. The cap is initially conical in shape, before becoming convex and then flattening out; it may reach dimensions of up to 1.5 cm (0.6 in) across. The cap color is ivory-white to yellowish white, sometimes more yellowish at the center. The tubular stems are up to 8 cm (3.1 in) long and 2.5 mm (0.10 in) thick, and have long, coarse white hairs at their bases. The mushroom is found in Europe, the Middle East, and North America, where it grows scattered or in dense groups under conifers and on humus in oak woods.