This extremely rare mushroom is notable for its unusual appearance and disjunct distribution; it is found only in select locales in Texas and Japan.

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 bodies were first collected in Austin, Texas, and the species was named Urnula geaster in 1893; later, it was found in Kyushu in 1937, but the mushroom was not reported again in Japan until 1973.

Phylogenetic analyses of the past decade have clarified the fungus's classification: Chorioactis, along with three other genera, make up the family Chorioactidaceae, 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 lifecycle; this asexual state was named Kumanasamuha geaster.

[9][10] A 1983 monograph on the family included Chorioactis in the tribe Sarcosomateae (along with the genera Desmazierella, Sarcosoma, Korfiella, Plectania, and Urnula), a grouping of fungi characterized by having spores lacking small, wart-like projections (verruculae) capable of absorbing blue dye.

[11] A 1994 study of the structural features of the asci and the ascospores concluded that Chorioactis was more closely aligned with the Sarcoscyphaceae, although it conceded that the layering of the cells comprising the walls of the ascus differed considerably from the other members of the family.

[12] It was not until 1999 that the results of phylogenetic analysis firmly challenged the traditional classification, showing C. geaster to be part of a distinct lineage, or clade, that includes species in the genera Desmazierella, Neournula, and Wolfina, taxa that were distributed among both families.

[15] Although C. geaster shares some characteristics with the other Chorioactidaceae genera, including dark-colored superficial "hairs" on the outer surface of the fruit bodies, it is distinguished from them by its tan to orange (rather than black) hymenia.

[16] The specific epithet geaster alludes to members of genus Geastrum, which also open to form star-shaped fruit bodies commonly called 'earthstars'.

[20] In Japan the mushroom is called kirinomitake (キリノミタケ), because the immature, unopened fruit body bears a superficial resemblance to the seed pods of kiri, the empress tree (Paulownia tomentosa).

The spores are borne on the inner surface of the rays, which, depending on the maturity of the specimen, may range in color from whitish to saffron to salmon to butterscotch to chestnut.

[23] The spore puffing upon rupture is thought to be caused by the sudden change in relative humidity between the interior chamber of the fruit body and the outside environment.

However, the operculum of C. geaster develops a two-layered ring zone upon dehiscence, making it structurally distinct from members of both the Sarcosomataceae and the Sarcoscyphaceae families.

[16] The swelling of the paraphyses is believed to cause the expansion of the hymenium and subsequent splitting of the fruit body into rays; this development places the asci into an optimal position for spore release and dispersal.

[3] When viewed with electron microscopy, the dark brown "hairs" on the surface of the fruit body can be seen to be adorned with conical warts or spines.

By comparing the internal transcribed spacer region of the nuclear ribosomal DNA from the two organisms, they established a phylogenetic connection between Chorioactis and the fungus they called Conoplea aff.

[5] In Texas, fruit bodies usually appear between October and April, as this period is associated with somewhat cooler weather, and the temperature and moisture conditions during this time seem to be more favorable for growth.