Parasola glabra Hussain, Afshan, Ahmad & 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 : 44-46

Parasola glabra Hussain, Afshan, Ahmad & Khalid sp. nov. Figures 4, 5

Diagnosis.

The diagnostic features of Parasola glabra are grayish pileus, deeply plicate towards margin; disc slightly depressed, strong reddish orange; lamellae free, separated from the stipe by pseudocollarium; basidiospores 14.5-16.5 × 9.5-11.5 × 8.0-10.5 µm, in front view broadly ovoid to oblong, some with rhomboidal outline, in side view ellipsoid, with eccentric germ-pore of 1.5 µm diam.

Type.

PAKISTAN. Khyber Pakhtunkhwa Province, Malakand, Qaldara, scattered under herbaceous plants, 480 m alt., 15 August 2014, S. Hussain SHP5 (holotype: LAH SH-P5; GenBank accessions: ITS = KY461717; 28S = KY621806; TEF1α = KY461735).

Description.

Pileus 20-30 mm diam, initially subglobose, later convex to hemispheric; at first smooth, without veil, the center glabrous at maturity, becoming deeply plicate towards the margin; light gray (2.5R 6/2) to moderate gray (7.5R 6/2); disc slightly depressed, strong reddish orange (7.5R 5/12). Lamellae free, fairly crowded, separated from the stipe by pseudocollarium, 0-2 lamellulae, regular, initially whitish, then dark brown becoming black at maturity, finally losing turgor and collapsing. Stipe 30-60 × 2-3 mm, central, equal, smooth, slightly sub-bulbous at the base, hollow, white, fragile, without annulus.

Basidiospores (13)14.5-16.5(18) × (7.5)9.5-11.5(15) × (9)8.0-10.5(11.5) µm, on average 15.8 × 10.9 × 10.1 µm, Q1 = 1.3-1.5, Q2 = 1.4-1.6, avQ = 1.4; in face view broadly ovoid to oblong, some with rhomboidal outline, in side view ellipsoid, germ-pore eccentric and upto 1.5 µm diam; wall upto 1.5 µm thick, dark brown to blackish in KOH. Basidia 28-41 × 10-13 µm, clavate to cylindrical, 4-spored, hyaline in KOH. Cheilocystidia 50-63 × 17-23 µm, oblong, ellipsoid, narrowly to broadly utriform, hyaline. Pleurocystidia 60-75 × 22-38 µm, clavate to broadly lageniform, hyaline. Pileipellis hymeniform, consisting of clavate cells 47-60 × 13-16 µm, bright yellow at the base in KOH. Clamp connections present mostly in the pileipellis and at the base of basidia. Sclerocystidia absent.

Habitat and distribution.

Saprotrophic, scattered under herbaceous plants on grass land. So far only known from the lowland of northern Pakistan. This species is, however, common in lowland northwest Pakistan.

Etymology.

Specific epithet ' glabra ' refers to the glabrous cap found in species of section Parasola of the genus Parasola , where this species belongs.

Additional specimen examined.

PAKISTAN, Khyber Pakhtunkhwa Province, Malakand, Qaldara, 480 m alt., 28 May 2015, S. Hussain SHP23 (HUP SHP-23).

Comments.

The distinguishing features of the new species P. glabra are: basidiospores broadly ovoid to oblong, some with rhomboidal outline in face view, ellipsoid in side view, on range 14.5-16.5 × 9.5-11.5 × 8.0-10.5 µm, pileus light gray to moderate gray but reddish orange at the disk, without sclerocystidia. Lacking sclerocystidia, P. glabra belongs in section Parasola . On basidiospore dimensions, it could be thought close to P. plicatilis and P. megasperma (P.D. Orton) Redhead, Vilgalys & Hopple but these are distinguishable on the basis of spores shape, length and breadth together and on the color of the cap disk. Using maximum likelihood phylogeny, these two species are clearly distinct from P. glabra and, based on ITS and 28S loci, the more closely related species are: P. hercules ( Uljé & Bas) Redhead, Vilgalys & Hopple; P. kuehneri ( Uljé & Bas) Redhead, Vilgalys & Hopple; P. lilatincta and P. schroeteri (P. Karst.) Redhead, Vilgalys & Hopple. The new species can be distinguished from these species on account of basidiospore morphology: among these species, P. hercules has the largest spore breadth (11.3-16.9 µm), followed by P. schroeteri (9-13 µm), P. glabra (9.5-11.5 µm), P. lilatincta (9-11.2 µm) and smallest spore breadth (5.5-8.4 µm) in P. kuehneri . On the basis of basidiospore length/breadth ratio (Q1), the new taxon P. glabra (Q1 = 1.3-1.5), can be easily distinguished from these species: in P. hercules (Q1 = 1.04-1.28), P. schroeteri (Q1 = 1.16-1.27), P. lilatincta (Q1 = 1.14-1.33) and P. kuehneri (Q1 = 1.12-1.28), respectively ( Nagy et al. 2010, Schafer 2014). Comparison of morphological characters of P. glabra with regards to these and other species of section Parasola genus Parasola are set out further in Table 2.