Cyathus uniperidiolus P.N. Singh & S.K. Singh, sp. nov.
Index Fungorum number: IF 556766; MycoBank number: MB 556766; Facesoffungi number: FoF 06586; Fig. 1
Etymology – specific epithet ‘uniperidiolus’ refers to single peridiole in basidiocarp.
Holotype – AMH10196
Colour codes follow – Methuen Handbook of Colour (Kornerup and Wanscher 1978).
Saprobic on dead bamboo grass of Muhlenbergia in a terrestrial habitat. Asexual morph Undetermined. Sexual morph Basidiocarp (peridia) are of two types viz. globose to sub-globose, like small cannon balls, abundant and rarely fluted/deeper, sessile to short stalked, attached to substrate with brownish bulging pad, dark brown 2–12 mm high and 2–3.5 mm wide at mouth with serrate margin. Exterior wall of the peridium dark brown (6F8), with slightly velvety surfaces, non-plicate. Interior wall of the peridium, dark brown (6F8), nonplicate, smooth walled. Peridial wall up to 78 µm thick, made up of terminal and subterminal thick and thin encrusted cells of peridial hairs, 2.7–7.15 µm wide. Peridioles, produced singly in each basidiocarp, sessile (funicular cord hard to observe), globose, resembling small cannonballs, hard, smooth, black with shiny surfaces, 2–2.5 mm diam. Transverse section of peridiole showed four layered: cortex, subcortex, hymenium and innermost layer is emptied. Cortex thick and black, compact, hard to observe the cells, up to 103.5 µm thick. Subcortex layer is made up of compact pseudoparenchymatous cells, light olivaceous to subhyaline, up to 642.7 µm thick. Hymenium (fertile layer) up to 275.9 µm thick composed of hyaline hyphae and spore mass, the fourth inner layer is emptied as in coconut. Basidiopores broadly ellipsoid to ellipsoid-elongate, rarely oval to sub-globose, thick and smooth walled, hyaline, amyloid, 14.2–28.7×11.7–23.7 µm (x̅=21.8×16 µm, n=30).
Culture characteristics – on MEA (Malt Extract Agar), fast growing, floccose, white (1A1), 61×61 μm diam. in 8 days at 25 °C, margin irregular, reverse pale yellow (3A3). Exudates produced in the form of droplets, yellow. Hyphae septate, branched, clamped, smooth walled, sub hyaline to light olivaceous, 2.1–7 μm wide. Globose to sub-globose yellowish brown (5E8) basidiocarps produced abundantly which bears single globose black peridiole in each basidiocarp which was entirely covered with thin velvety peridial wall.
Material examined – INDIA, Maharashtra, Pune District, dead stem of Muhlenbergia sp (Poaceae), 30 August 2017, P.N. Singh (AMH 10196, holotype), ex-type living culture (NFCCI 4697), National Fungal Culture Collection of India (WDCM932).
GenBank Numbers – ITS=MN398297, LSU=MN398298.
Notes – The present taxon was isolated in pure cultures from the basidiocarp associated with dead stem of Muhlenbergia sp. (Bamboo grass). The macro and micromorphological characters such as basidiocarp and peridioles, multi-layered peridiolar wall, and globose blackish peridioles, broadly ellipsoid to ellipsoid-elongate, hyaline, smooth-walled basidiospores (Fig. 1), place this taxon under Cyathus (von Haller 1768; Baseia and Milanez 2001). Present species is distinct from its allied taxa in having unique shape of peridia and peridioles i.e., globose, small cannon ball-like, produced abundantly, deeper or fluted, are rarely produced. These characteristic features clearly separate present taxon from allied Cythus spp., viz. C. albinus, C. badius, C. renweii, C. poeppigii, C. thindii and C. striatus (type species) (Table 1) (von Willdenow 1787; Tulasne and Tulasne 1844; Kobayasi 1937; Zhou et al. 2004; Cruz et al. 2014, 2018; Das et al. 2015; Accioly et al. 2018). As such these are the distinct and unique features of the proposed species. The other morphological features are also compared in Table 1. The phylogenetic analysis reveals that C. uniperidiolus forms a distinct sister clade with C. badius which is statistically supported (Fig. 2). From morphological data and sequence analyses it is evident that C. uniperidiolus is distinct from all other species in the genus. Therefore, Cyathus uniperidiolus is described and illustrated here as a new species.
Figure 1 – Cyathus uniperidiolus (AMH-10196, holotype, NFCCI4697 ex-type culture). a Substrate (stem of Muhlenbergia sp. with attached basidiocarps). b Basidiocarps bearing single globose peridiole. c Globose peridioles with shiny surfaces. d Sections of peridioles showing emptied cavity inside. e Transverse section of basidiocarp showing different layers, innermost region showed emptied. f Transverse section of peridiole showing layer of cortex and sub-cortex (a part view). g Terminal and subterminal thick-walled encrusted loose and interwoven cells of basidiocarp. h Hymenial layer with hyphae and basidiospores. i Enlarged view of basidiospores. j Colony morphology on MEA (front view). k Colony with developing basidiocarps. l Harvested basidiocarps with velvety surfaces from culture. m Hyphae with clamps. Scale bars: f–i, m=10 μm
Table 1 Morphological comparison of Cyathus uniperidiolus with some allied taxa
Figure 2 – Phylogram generated from maximum likelihood analysis for Cyathus uniperidiolus (NFCCI: 4697) using combined ITS and LSU sequence data based on the General Time Reversible model (Nei and Kumar 2000). A discrete Gamma distribution was used to model evolutionary rate differences among sites (5 categories (+G, parameter=0.2814)). Bootstrap support values are indicated at the nodes and values below 50% are not shown. Phylogenetics analyses were conducted in MEGA7 (Kumar et al. 2016). Nidula niveotomentosa SWFC 3000, Crucibulum leave SWFC 21,261 and Cystoderma amianthinum AFTOL-ID 1553 were used as outgroup. Type specimens are in bold and newly sequence is in blue