Parasola pseudolactea Sadiqullah, Hussain & Khalid

Hussain, Shah, Ahmad, Habib, Ullah, Sadiq, Afshan, Najam-Ul-Sehar, Pfister, Donald H., Sher, Hassan, Ali, Haidar & Khalid, Abdul N., 2018, The genus Parasola in Pakistan with the description of two new species, MycoKeys 30, pp. 41-60 : 46-48

Parasola pseudolactea Sadiqullah, Hussain & Khalid sp. nov. Figures 6, 7

Diagnosis.

Pileus yellowish brown to dull brown, deeply plicate towards margin; disc subumbilicate, deep orange yellow; lamellae free, pseudocollarium absent; basidiospores 13.5-14.5 × 10.5-12.0 × 9.5-10.5 µm, in face view rounded triangular to heart shape, rarely ovoid to subglobose, in side view ellipsoid to oblong, with eccentric germ-pore of 1.5 µm diam; sclerocystidia absent.

Type.

PAKISTAN, Khyber Pakhtunkhwa Province, Shangla, solitary to scattered under Quercus incana , 1480 m alt., 9 July 2014, Sadiq Ullah SU412 (holotype: HUP SU-412; GenBank accessions: ITS = KY461719; 28S = KY621799; TEF1α = KY461733).

Description.

Pileus 15-25 mm diam, initially obtusely conical, later becoming applanate and deeply plicate towards margin; yellowish brown to dull brown (10YR 6/4) when young, moderate gray (7.5R 6/2) on maturity; disk subumbilicate, deep orange-yellow (7.5YR 6/12). Lamellae free, 0-2 lamellulae, distant, pseudocollarium absent, initially dark gray, becoming blackish at maturity and finally losing turgor and collapsing. Stipe 30-50 × 1 mm, equal, smooth, grayish-brown, translucent, hollow, without annulus.

Basidiospores (12.0)13.5-15.0(16.0) × (9.5)10.5-12.0(13.0) × (7.5)9.5-10.5(12.0) µm, on average 14.0 × 11.3 × 9.7 µm, Q1 = 1.3-1.5, Q2 = 1.4-1.5, avQ = 1.4; in face view mostly rounded triangular to heart shaped, rarely ovoid to subglobose, in side view ellipsoid to oblong, with eccentric germ pore of 1-1.5 µm diam, dark to blackish in KOH. Basidia 24-31 × 8-12 µm, clavate to cylindrical, 4-spored. Cheilocystidia 55-70 × 22-29 µm, clavate, broadly clavate to broadly cylindrical. Pleurocys tidia 44-67 × 19-23 µm, utriform to lageniform. Pileipellis hymeniform, consisting of clavate cells, 33-38 × 17-22 µm. Clamp connections present. Sclerocystidia absent.

Habitat and distribution.

Solitary to scattered on humus rich loamy soil, under Quercus incana . So far only known from northwest Pakistan.

Etymology.

The prefix “pseudo” means similar and " lactea " refers to the epithet of the species ( Parasola lactea ) that this species closely resembles. This species is known so far from low to moderate altitude mountains of northwest Pakistan.

Additional specimens examined.

PAKISTAN, Khyber Pakhtunkhwa Province, Shangla, 1480 m alt., 9 July 2014, Sadiq Ullah SU413 (HUP SU-413).

Comments.

The new species belongs to Parasola section Parasola due to the absence of sclerocystida in the pileipellis. This species resembles Parasola lactea and is close to that species in the molecular phylograms. However, its spores are substantially larger, closer to P. schroeteri or P. hercules in size. The spores of P. pseudolactea are mostly rounded triangular, rarely ovoid to subglobose in face view and larger (14.0 × 11.3 × 9.7 µm), whereas those of P. lactea are mostly broadly ovoid to subglobose, rarely rounded triangular in face view, and comparatively smaller (10.73 × 8.81 × 6.73 μm). Other species similar to the new taxon are P. megasperma and P. plicatilis . Both these species share pileus color with P. pseudolactea . Lamellae of P. megasperma and P. plicatilis are separated from the stipe by a pseudocollarium, whereas in P. pseudolactea , a pseudocollarium is generally absent. Basidiospores are more ellipsoid rarely ovoid in face view and on average 16.5 × 10.66 × 8.5 μm in P. megasperma . Basidiospore shape is quite variable in P. plicatilis , in face view mostly limoniform-subhexagonal, rarely ovoid, in side view broadly ellipsoid, on average 12.41 × 8.21 × 7.14 μm ( Nagy et al. 2010). Comparison of morpho-anatomical features of P. pseudolactea with regards to other species of the genus Parasola are set out in Table 2, where the new species can be differentiated by careful comparison of the morphology of its basidiospores.