Yunnan earthstar (Geastrum yunnanense Geastrales, Basidiomycota) from Yunnan in Southwest China

NEWS - Yunnan earthstar (Geastrum yunnanense) from Yunnan Province in Southwest China is a new member of the genus based on morphological and molecular evidence characterized by round or oval endoperidia, shallow exoperidia and round basidiospores (diameter 2.0-2.5 × 1.9-2.5 μm).

In ecology and biogeography, the family Geastraceae is an extensively studied group of Basidiomycota and an important group in forest ecosystems. However, its diversity in China is still poorly understood.

Researchers from Southwest Forestry University in Kunming established the new species based on phylogenetic analysis and morphological characteristics. Phylogenetic analysis of internal transcribed spacers (ITS) and large subunit (nrLSU) sequence data sets of the nuclear ribosomal DNA (rDNA) markers showed G. yunnanense is close to G. velutinum and G. javanicum.

However, morphologically G. velutinum differs from G. yunnanense because it has a mycelial layer that is easily detached and larger basidiospores (3-4 μm in diameter). G. javanicum differs from G. yunnanense because the exoperidium is very sac-shaped, the capillary hyphae are without branches and the basidiospores are larger (3.0-4.0 μm in diameter).

Morphologically, G. morganii Lloyd, G. saccatum Fr., G. pseudosaccatum T. Bau & X. Wang, G. yanshanense C.L Hou, Hao Zhou & Jiqi Li, G. suae Z.Q. Zhang, C.H. Li & Z.L. Luo, G. melanorhynchum T. Bau & X. Wang and G. oxysepalum T. Bau & X. Wang are similar to G. yunnanense based on sessile endoperidia and mycelial layer without flakes.

However, G. morganii differs based on larger basidiospores (4-5.5 μm in diameter). G. saccatum with a peristome that has a clear oral edge ring and the mycelial layer is easily detached. G. pseudosaccatum with a peristome that has a ring with prominent and unbranched capillary hyphae.

G. yanshanense differs with deep and expanded basidiomata, peristome with a clear oral edge ring and clear columella. G. suae with a long stalk, larger basidiomata (35-70 mm high, 18-37 mm in diameter), peristome with a clear oral edge ring and clear columella.

G. melanorhynchum with a peristome with a clear oral edge ring and dehiscence of the exoperidium which is often larger than half. G. oxysepalum with a peristome with a clear oral edge ring and unbranched capillary hyphae.

G. laneum T. Bau & X. Wang, G. microphole T. Bau & X. Wang and G. mongolicum T. Bau & X. Wang are similar to G. yunnanense with a fibrous layer attached to the mycelial layer. However, G. laneum differs with a soft and thin exoperidium, unbranched capillary hyphae and crusted with a flaky mycelial layer.

G. microphole differs in that the mycelial layer is easily detached and crusted with flakes, the endoperidial body is stipitate and has an apophysis. G. mongolicum differs in that the mycelial layer is easily detached and crusted with flakes and the exoperidium is curved or deep sac-like.

Original research

Xin Yang, Jiangqing Su, Hongmin Zhou & Changlin Zhao (2024). Morphological characteristics and phylogenetic analyses revealed Geastrum yunnanense sp. nov. (Geastrales, Basidiomycota) from Southwest China. Phytotaxa 665 (3): 179-192, DOI:10.11646/phytotaxa.665.3.1

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