Coprinellus disseminatus-similis Hussain

Hussain, Shah, Usman, Muhammad, Afshan, Najam-ul-Sehar, Ahmad, Habib, Khan, Junaid & Khalid, Abdul Nasir, 2018, The genus Coprinellus (Basidiomycota; Agaricales) in Pakistan with the description of four new species, MycoKeys 39, pp. 41-61 : 45-46

Coprinellus disseminatus-similis Hussain sp. nov. Figures 1 A–Band 5

Diagnosis.

The most important features of Co. disseminatus-similis are: pileus parabolic to campanulate, greyish-brown, with umbonate centre; surface pruinose to pulverulent, with sparse micaceous-glistening veil, bright white, deeply plicate from centre to margin; basidiospores 8.0-9.0 × 5.0-5.5 × 4.5-5.5 µm, in face view ellipsoid to cylindrical or obovoid, in side view ellipsoid to amygdaliform, smooth, thick-walled, with truncate base, germ-pore central, 0.5-1.0 µm wide.

Type.

PAKISTAN: Khyber Pakhtunkhwa, Malakand, Sarogai, 450 m alt., gregarious on wood chips, 23 Sept 2014, S. Hussain, SHCr3w (SWAT-SHCr3w, holotype); GenBank accession ITS: MH753670.

Etymology.

“Similis” (Latin) meaning like, referring to the similarity of the new species to Coprinellus disseminatus .

Macroscopic characters.

Pileus at young stage cylindrical and closed, 3-5 × 3-7 mm, whitish to light greyish (2.5Y 7/4), surface pruinose, slightly plicate toward margin; at mature stage 15−20 × 20 mm, parabolic to campanulate to umbonate, light greyish-brown (7.5YR 6/2) to greyish-yellowish-brown (7.5YR 6/2); with umbonate centre, in old specimens centre papillate, centre moderate orange (2.5YR 6/8) to brownish-orange (2.5YR 5/8); surface pruinose to pulverulent, with sparse micaceous-glistening veil, bright white, deeply plicate from centre to margin; context membranous. Lamellae sinuate to uncinate, distant with 0-2 lamellulae, initially white, fading with age and dark greyish-brown at maturity. Stipe 20−40 × 1 mm, equal, central, white, surface pruinose to pulverulent with sparse micaceous-glistening veil, context hollow, annulus absent. Odour pungent, not tasted.

Microscopic characters.

Basidiospores (7.5 –)8.0–9.0(– 9.5) × (4.5 –)5.0–5.5(– 6.0) × (4.0 –)4.5–5.5(– 6.0) µm, on average 8.5 × 5.2 × 4.9 µm, Q1 = 1.53-1.7, Q2 = 1.7-1.9, av. Q = 1.6; in face view, ellipsoid to cylindrical or obovoid, in side view, ellipsoid to amygdaliform, dark brown to blackish in KOH, smooth, thick-walled, with truncate base, germ-pore central, 0.5-1.0 µm wide. Basidia 26−30 × 7−10 µm, clavate to cylindrical, 2 to 4−spored, hyaline. Cheilocystidia 70−165 × 11−15 µm, cylindrical, narrowly clavate to narrowly utriform, some with subcapitate apex, abundant, smooth, hyaline. Pleurocystidia absent. Pileipellis a loosely arranged euhymeniderm with narrowly utriform to utriform pileocystidia, 118−165 × 23−28 µm, light-brownish to hyaline, smooth. Veil elements 20-40 µm, globose to subglobose, greyish-brown, smooth. Clamp connection not observed.

Habitat and distribution.

Gregarious on leaf litter under Populus alba and Morus alba , so far only known from lowland northern Pakistan.

Additional specimens examined.

PAKISTAN. Khyber Pakhtunkhwa: Malakand, Sarogai, on leaf litter under Populus alba and Morus alba , 22 Sept 2014, S. Hussain, SH-Cr3-b (SWAT SH-Cr3-b).

Comments.

The new species would be placed in sect. Setulosi because of its pileocystidia. However, as with Co. disseminatus , which it resembles and is close to in the molecular phylogram, Co. disseminatus-similis falls in a clade along with members of section Micacei that lack such pileocystidia, underlining the need to update the formal description of the sections. Both these species share basidiospore morphology. However, they differ on the basis of: (i) pileus shape and colour, (ii) cheilocystidia and (iii) pileocystidia and veil anatomy. In Co. disseminatus , initially the pileus is (sub)globose or ovoid, then hemispherical or obtusely conical to convex, rarely flat, the fruit bodies often form in very large groups and are initially very pale, almost white, darkening as the spores mature; cheilocystidia are absent along most of the gill edge; pileocystidia are lageniform with cylindrical neck and rounded, rarely subcapitate, apex and large 50-200 × 15-24 µm; and veil elements are globose to subglobose, generally with golden brown incrustations ( Uljé and Bas 1991, Uljé 2005). In Co. disseminatus-similis , at young stage, the pileus is cylindrical and closed, parabolic to campanulate to umbonate at mature stage, with papillate centre in some old specimens; cheilocystidia are large (70−165 × 11−15 µm), narrowly clavate to narrowly utriform, some with subcapitate apex; pileocystidia are narrowly utriform to utriform; and veil elements are globose to subglobose and smooth. Using ML and Bayesian analyses, Coprinellus verrucispermus (Joss. & Enderle) Redhead, Vilgalys & Moncalvo is another species close to Co. disseminatus-similis . Spores in Co. verrucispermus are substantially larger (11.0-14.5 × 7.0-9.0 µm), ellipsoid to slightly amygdaliform, chestnut brown, apiculus slight, warty with perisporial sac and central germ pore ( Uljé and Bas 1991, Keirle et al. 2004).