''Geasteroides'' is a fungal

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

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 Pha ...

. A

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus, it contains the single species ''Geasteroides texensis'', described by American mycologist William Henry Long in 1917.

Taxonomy

Long described both the new genus and species in a 1917 article in the journal ''

Mycologia ''Mycologia'' is a peer-reviewed scientific journal that publishes papers on all aspects of the fungi, including lichens. It first appeared as a bimonthly journal in January 1909, published by the New York Botanical Garden under the editorship of W ...

''. The type collection was made in

Denton, Texas Denton is a city in and the county seat of Denton County, Texas, United States. With a population of 139,869 as of 2020, it is the 27th-most populous city in Texas, the 197th-most populous city in the United States, and the 12th-most populous ...

in October 1907. Long called it "a ''

Calvatia ''Calvatia'' is a genus of puffball mushrooms that includes the spectacular giant puffball ''C. gigantea''. It was formerly classified within the now-obsolete order Lycoperdales, which, following a restructuring of fungal taxonomy brought ...

'' among the geaster". In 1945, Long replaced the name with ''Terrostella'', suggesting that ''Geasteroides'' was illegitimate because it had been used by Giovanni Antonio Battarra in 1755. However, later changes in the

nomenclatural Nomenclature (, ) is a system of names or terms, or the rules for forming these terms in a particular field of arts or sciences. The principles of naming vary from the relatively informal conventions of everyday speech to the internationally ag ...

rules meant that names of

gasteroid The gasteroid fungi are a group of fungi in the Basidiomycota. Species were formerly placed in the obsolete class Gasteromycetes Fr. (literally "stomach fungi"), or the equally obsolete order Gasteromycetales Rea, because they produce spores ins ...

species published before 1801 no longer had priority, rendering ''Terrostella'' illegitimate.

Patricio Ponce de León Patricio Ponce de León (August 26, 1915 – February 26, 2010) was a Cuban mycologist. He was a professor at Belen School in Havana and at the University of Havana, and later a curator at the Field Museum of Natural History in Chicago, Illinois. ...

transferred the Congolese species ''Geastrum barbatum'' (described by Dissing & M. Lange in 1962) to ''Geasteroides'' in 1968, but this has since been transferred to the genus '' Phialastrum''.

Description

''Geasteroides texensis'' has a fruit body that splits open in maturity in a star-like fashion to reveal a spherical inner spore sac (

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 continu ...

). The ochre to whitish outer layer of skin, the

exoperidium 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 rubber ...

, is thick and leathery and often has a thin layer of adhering cobweb-like

mycelium 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 substrate (biology), substrates. A typical single ...

and debris that peels away as the fungus matures. The exoperidium splits open into four to seven rays that are curved backward overall, with tips curved inward. Expanded fruit bodies are in diameter. The inner surface of the exoperidum is dark brown, with deep cracks when dry. The special inner endoperidium rests upon a short stipe that broadens to a top-shaped, corky base. The height of base and endoperidium is , and it is roughly the same width. The fragile, whitish to brownish endoperidium opens irregularly near the top to reveal purplish-brown gleba. In some mature, weathered specimens, the gleba may be completely absent, with only the interior stipe and corky base remaining in the endoperidium. 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, f ...

s are spherical with faint warts on the surface, and measure 3–5 µm in diameter.

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 kn ...

threads in the gleba are long and sparingly branched, measuring 7–10 µm thick.

Habitat and distribution

The species is known from Texas, where it grows in

loam Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–sil ...

y soil around the decaying stumps of

post oak ''Quercus stellata'', the post oak or iron oak, is a North American species of oak in the white oak section. It is a slow-growing oak that lives in dry areas on the edges of fields, tops of ridges also grows in poor soils, and is resistant to ro ...

(''Quercus stellata'').

References

{{Taxonbar, from=Q3018215 Fungi of the United States Geastraceae Monotypic Basidiomycota genera