''Geastrum leptospermum'' is a species of

fungus A fungus (plural, : fungi or funguses) is any member of the group of Eukaryote, eukaryotic organisms that includes microorganisms such as yeasts and Mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified ...

in the family

Geastraceae Geastrales is an order of gasterocarpic basidiomycetes (fungi) that are related to Cantharellales. The order contains the single family Geastraceae, commonly known as "earthstars", which older classifications had placed in Lycoperdales, or ...

. It was first described scientifically by American mycologist

George F. Atkinson George Francis Atkinson (January 26, 1854 – November 14, 1918) was an American botanist and mycologist.Makers of American Botany, Harry Baker Humphrey, Ronald Press Company, Library of Congress Card Number 61-18435 He was born on January 26, ...

in 1903. The fungus produces small

fruit bodies The sporocarp (also known as fruiting body, fruit body or fruitbody) of fungi is a multicellular structure on which spore-producing structures, such as basidia or asci, are borne. The fruitbody is part of the sexual phase of a fungal life c ...

and grows in

mosses Mosses are small, non-vascular flowerless plants in the taxonomic division Bryophyta (, ) ''sensu stricto''. Bryophyta ('' sensu lato'', Schimp. 1879) may also refer to the parent group bryophytes, which comprise liverworts, mosses, and h ...

on tree trunks.

Description

The inner

peridium The peridium is the protective layer that encloses a mass of spores in fungi. This outer covering is a distinctive feature of gasteroid fungi. Description Depending on the species, the peridium may vary from being paper-thin to thick and rubbe ...

, or spore sac, is nearly spherical, thick, pale gray to pale tan in color, and dusted with fine whitish particles that also cover the inner surface of the freshly opened rays. The mouth on the apex of the peridium is very small, minutely fibrous, and surrounded by a conical, white disc which is distinctly outlined and radially fibrous (if not deeply grooved). As the fruit body matures, the fibrous layer of the outer peridium splits, star-like, into three to six rays about halfway down or more. The fungus is ''fornicate'', meaning that the rays curve downward so that the base of the fruit body becomes arched up, which elevates the spore sac. This leaves its delicate fibrous,

mycelial Mycelium (plural mycelia) is a root-like structure of a fungus consisting of a mass of branching, thread-like hyphae. Fungal colonies composed of mycelium are found in and on soil and many other substrates. A typical single spore germinates in ...

layer as a distinct, membranous, white cup on the underside, with its margin also rayed by slits, the rays attached to the rays of the plant above. When freshly opened, the inner surface of the rays is covered with a fleshy, pale

buff Buff or BUFF may refer to: People * Buff (surname), a list of people * Buff (nickname), a list of people * Johnny Buff, ring name of American world champion boxer John Lisky (1888–1955) * Buff Bagwell, a ring name of American professional wr ...

, layer of tissue. This layer, when dry, forms the thin, tan or light brown, smooth and nearly complete membrane over the fibrous layer. The underside of the rays is white and smooth. There is no obvious columella (sterile tissue in the base of the

gleba Gleba (, from Latin ''glaeba, glēba'', "lump") is the fleshy spore-bearing inner mass of certain fungi such as the puffball or stinkhorn. The gleba is a solid mass of spores, generated within an enclosed area within the sporocarp. The conti ...

that extends into the gleba). The

spore 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, ...

s are spherical and measure 2–3

μm The micrometre ( international spelling as used by the International Bureau of Weights and Measures; SI symbol: μm) or micrometer (American spelling), also commonly known as a micron, is a unit of length in the International System of Uni ...

. Under high power microscopy they appear as having a surface that is roughened by many small points or warts. The

capillitium Capillitium (pl. capillitia) is a mass of sterile fibers within a fruit body interspersed among spores. It is found in Mycetozoa (slime molds) and gasteroid fungi of the fungal subdivision Agaricomycotina The subdivision Agaricomycotina, also ...

(coarse, thick-walled cells in the gleba) threads are unbranched, and measure about 3 μm thick. Both the spores and the capillitium are whitish to very pale yellow-brown.

References

External links

* {{Taxonbar, from=Q5529521

leptospermum ''Leptospermum'' is a genus of shrubs and small trees in the myrtle family Myrtaceae commonly known as tea trees, although this name is sometimes also used for some species of ''Melaleuca''. Most species are endemic to Australia, with the great ...

Inedible fungi Fungi described in 1903 Fungi of North America