Lignosus

Lignosus
Lignosus rhinocerus
Scientific classification
Domain:	Eukaryota
Kingdom:	Fungi
Division:	Basidiomycota
Class:	Agaricomycetes
Order:	Polyporales
Family:	Polyporaceae
Genus:	Lignosus Lloyd ex Torrend (1920)
Type species
Lignosus sacer (Afzel. ex Fr.) Torrend (1920)

Lignosus is a genus of polypore fungi in the family Polyporaceae. The genus was circumscribed in 1920 by mycologists Curtis Gates Lloyd and Camille Torrend, with L. sacer as the type species.^[1]

Description

The fruit bodies of Lignosus fungi are annual. They have a cap that is coloured white to brown, with a central supporting stipe. The texture of the cap surface is smooth to very finely tomentose. Pores on the cap underside range in size from small to large. The stipe originates from a sclerotium in the ground. The hyphal system is trimitic. Generative hyphae have clamp connections and are hyaline. There are binding and skeletal hyphae in the context, sclerotium and the stipe. The hymenium lacks cystidia. Spores are smooth, ellipsoid, hyaline, and inamyloid.^[2]

Lignosus is similar in morphology to Microporus, but the fungi in this latter genus grow on wood and do not arise from a sclerotium. Microporus spores are cylindrical to allantoid (sausage-shaped).^[2]

Species

The genome of the species L. rhinocerus, the sclerotium of which is used as a traditional medicine in Southeast Asia, was published in 2014. Its genome is enriched with genes involved in the biosynthesis of sesquiterpenoid compounds.^[3] Eight species are known in Lignosus:

• L. cameronensis Chon S.Tan (2013) – Malaysia^[4]
• L. dimiticus Ryvarden (1975)
• L. ekombitii Douanla-Meli (2003) – Cameroon^[5]
• L. goetzei (Henn.) Ryvarden (1972)
• L. hainanensis B.K.Cui (2011) – Tropical China^[6]
• L. rhinocerus (Cooke) Ryvarden (1972)
• L. sacer (Afzel. ex Fr.) Torrend (1920)
• L. tigris Chon S.Tan (2013) – Malaysia^[4]

References

1. Torrend, C. (1920). "Les Polyporacées du Brésil. I. Polyporacées stipités". Brotéria Série Botânica (in French). 18: 121–143.
2. Ryvarden, L.; Johansen, I. A Preliminary Polypore Flora of East Africa. Oslo, Norway: Fungiflora. p. 405.
3. Yap, H.Y.; Chooi, Y.H.; Firdaus-Raih, M.; Fung, S.Y.; Ng, S.T.; Tan, C.S.; Tan, N.H. (2014). "The genome of the Tiger Milk mushroom, Lignosus rhinocerotis, provides insights into the genetic basis of its medicinal properties". BMC Genomics. 15 (1): 635. doi:10.1186/1471-2164-15-635. PMC 4129116. PMID 25073817.
4. Tam, C.S.; Ng, S.T.; Tan, J. (2013). "Two new species of Lignosus (Polyporaceae) from Malaysia — L. tigris and L. cameronensis". Mycotaxon. 123: 193–204. doi:10.5248/123.193.
5. Douanla-Meli, C.; Langer, E. (2003). "A new species of Lignosus (Polyporaceae) from Cameroon". Mycotaxon. 86: 389–394.
6. Cui, B.K.; Tang, L.P.; Dai, Y.C. (2011). "Morphological and molecular evidences of a new species of Lignosus (Polyporales, Basidiomycota) from tropical China". Mycological Progress. 10 (3): 267–271. doi:10.1007/s11557-010-0697-y.