Favolus septatus J.L. Zhou & B.K. Cui, Mycologia 109(5): 773 (2017)

Index Fungorum number: IF 817942; MycoBank number: MB 817942; Faces of fungi number: FoF 08019; Fig. 1

Colour codes follow – Methuen Handbook of Colour (Kornerup and Wanscher 1978)

Fruit bodies associated with dead wood of Dalbergia melanoxylon Guill. & Perr. (Fabaceae). Basidiocarps solitary or 1–2 in group, tough or leathery and flexible when fresh, fragile when dry, persistently attached with dead branches in the form of brackets, stipitate. Stipe short, up to 5 mm long and 7 mm diam. Pileus circular to flabellate, sometimes notched, fibrillose with flattened, radially striate, azonate, from base to tip up to 5.5 cm long ×3.5 cm wide. Pilial surface wet, buff to yellowish, smooth-walled. Pores surface buff when fresh, buff brown when dry, pores hexangular, radially elongated, 4–5 mm long, 1–2 mm wide near stipe to 1 per mm at margin. Context (internal tissue of the fruit body) has a tough and fleshy to leathery texture when fresh, buff brown, corky, brittle when dry, buff brown, up to 4 mm thick. Tube continuous with the context, up to 5–6 mm thick. Spore prints white. Hyphal system dimitic. Generative hyphae without clamp connection, hyaline in KOH, thin and smooth-walled, 1.8–5 μm. Skeletal-binding hyphae thick walled, aseptate, highly branched, hyaline, 2.5–6.5 μm. Cystidial cells absent. Basidia persistant, clavate, sometimes bulged, constricted near septa, septate, pigmented, 11.5–11.8×5.9–6.3 μm. Sterigmata persistent, straight to incurved, tip sub-obtuse, 2–4 in numbers per basidium, 1–2.4 μm (x̅=14.3×6 μm, n=6). Basidiospores, cylindric to oblong, pigmented, smooth and thin walled, hyaline, 6.5–9.5×3.3–4.3 μm.

Culture characteristics – Colonies on PDA (Potato Dextrose Agar), center pale yellow (4A3), periphery white (1A1), floccose, 7.5 cm diam. in 24 days. Margin irregular, reverse pale yellow (4A3). Hyphae septate, unbranched to branched, smooth and thin walled, subhyaline to light olivacous, sometimes coroloid, rope like, twisted, forming loose and compact parallel bundles of hyphae, pigmented or granulated. Chlamydospores produced from superficial hyphae, terminal to lateral, solitary, bulbus, stalked, up to 8.9×8.6 μm wide. Clamp connections in hyphae absent.

Material examined – INDIA, Maharashtra, Pune District, on dead wood of Dalbergia melanoxylon (Fabaceae), 17 July 2019, D.K. Maurya (AMH 10219, new record), living culture (NFCCI 4776).

GenBank numbers – ITS=MT372798, LSU=MT372843.

Notes – Phylogenetic analysis based on a combined ITS and LSU sequence dataset of 35 taxa shows that the Indian taxon (NFCCI 4776) clusters with type of Favolus septatus. A Megablast search of the ITS sequence shows 99.48% similarity (569/572) with Favolus septatus (Zhou 287, Type) (Fig. 2). In our observation, the morphological features, especially length and width of basidiocarps is somewhat larger in the present collection than originally described in Favolus septatus (Fig. 1). The pilial surface is buff to yellowish in the present collection, while it is pinkish buff to yellowish in the original description of F. septatus. However, based on similarity regarding other morphological characteristics, and phylogenetic analysis, similarity of the present collection is confirmed as Favolus septatus (Zhou and Cui 2017). As per our understanding, this is the first report of Favolus septatus being reported from India. Therefore, described and illustrated here.

Figure 1 – Favolus septatus (AMH 10219, new record). a Habitat. b Basidiomata growing on substrate. c Basidioma showing hexagonal pores on lower surfaces. d, e Basidia with sterigmata. f, g Basidiospores. h, i Generative hyphae. j Skeletal binding hyphae. k Culture on PDA after 24 days (surface view). l Simple and compact hyphal bundle. m, n Simple and rope like twisted hyphae. o Parallel loose bundles of hyphae. Scale bars: d–o=10 µm

Figure 2 – The phylogenetic tree has been generated using maximum likelihood analysis based on LSU and ITS sequence data. Thirty-five strains are included in the LSU and ITS combined analyses comprising 1532 sites of which 1202 were the conserved and 320 were the variable sites, and 264 parsimony-informative sites. Neofavolus species are used as the outgroup taxa. The optimal tree with a final likelihood value of − 5057.256 is presented. Estimated base frequencies were as follows: A=0.250, C=0.250, G=0.250, T=0.250; substitution rates AC=1.00000, AG=4.63563, AT=1.00000, CG=1.00000, CT=8.90564, GT=1.00000; gamma distribution shape parameter α=0.961. Bootstrap values for maximum likelihood (ML) equal to or greater than 50% are labeled on the nodes. Type sequences are in bold and newly generated sequence of Favolus septatus NFCCI 4776 is in blue bold