Fungalpedia – Note 2829, Riisgaardia
Riisgaardia. W.P. Wu & Y.Z. Diao.
Citation when using this data: Wenping Wu et al. 2022 – Fungalpedia.
Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1
Classification: Chaetosphaeriaceae, Chaetosphaeriales, Sordariomycetidae, Sordariomycetes, Pezizomycotina, Ascomycota, Fungi
Etymology: Named after the former CEO of Novozymes A/S, Steen Riisgaard, who made great contribution in promoting industrial biotechnology for sustainability.
Diagnosis: Similar to Stanjehughesia and Stanjehughesia synanamorph of Zanclospora in absence of conidiophores, monoblastic and determinate conidiogenous cells, and obclavate-rostrate, euseptate conidia, but differs phylogenetically.
Colonies effuse, hypophyllous, brown. Mycelium superficial, composed of septate, brown to dark brown hyphae. Teleomorph: Unknown. Anamorph: Conidiophores absent. Conidiogenous cells discrete, determinate, lageniform, subcylindrical, ampulliform, short, solitary or in groups from basal stroma, simple, brown to black, truncate at the apex. Conidial ontogeny holoblastic, 1 locus per conidiogenous cell, delimitated by 1 septum, maturation by diffuse wall–building, secession schizolytic. Conidia solitary, straight or slightly curved, narrowly obclavate to obclavate-rostrate, conical-truncate at the base, euseptate, pale brown to brown, smooth, subhyaline at the apex.
Ecology/Substrate/Host: Saprobes on rotten plant material.
Geographical distribution: China and Europe.
Notes: Riisgaardia is similar to Stanjehughesia and Stanjehughesia synanamorph of Zanclospora in absence of conidiophores, dark brown to black conidiogenous cells with truncate apex, and cylindrical, obclavate to obclavate-rostrate, multiseptate conidia, and in fact they can hardly be distinguished from each other on morphology (Subramanian 1991; Wu and Zhuang 2005; Seifert et al. 2011; Hsieh et al. 2021; Réblová et al. 2021a). However, in the phylogenetic tree generated from the integrated ITS and LSU data, they are clearly distinguished: species of Riisgaardia, together with several other Sporidesmium-like species, are clustered together with several chaetosphaeriaceous genera producing lateral phialides and hyaline conidia; while the type species of Stanjehughesia, S. hormiscioides, is clustered together with Exserticlava and Stephembruneria, both with brown and septate conidia.
Both ITS and LSU sequences were obtained from the studied strain of the type species, R. longispora. Based on ITS blast in NCBI’s GenBank, the closest matches to the strain 50731 include Cryptophiale fasciculata (GenBank MH758195, 90% identity) and Kionochaeta ivoriensis (GenBank NR_160149, 90% identity). Based on LSU blast in NCBI’s GenBank, the closest matches to the strain 50731 include Kionochaeta ivoriensis (GenBank MH872758, 98% identity), Cryptophiale udagawae (GenBank MN104619, 97% identity) and Riisgaardia vermiculata (GenBank DQ408570, 97% identity).
Type species: Riisgaardia longispora W.P. Wu & Y.Z. Diao.
Other accepted species: Species Fungorum – search Riisgaardia.
Figure 1 – Riisgaardia longispora (Wu8333, holotype). a–h Conidia. i–k Conidiogenous cells. Scale bar: a, b, k 10 μm, c–j 5 μm
References
Seifert KA, Morgan-Jones G, Gams W, Kendrick WB 2011 – The genera of Hyphomycetes. CBS biodiversity series, vol 9. CBSKNAW Fungal Biodiversity Center, Utrecht, pp 1–997.
Entry by
Wenping Wu, R&D Center, Novozymes China, No. 14 Xin Xi Lu, Shangdi Zone, Haidian District, Beijing 100085, P.R. China
Published online 22 July 2026