Mallocybe pinicola Saba & Khalid, 2023

Saba, Malka, Khalid, Abdul Nasir & Sarwar, Samina, 2023, New species of Mallocybe (Agaricales, Inocybaceae) from Pakistan, based on morphological, MycoKeys 99, pp. 171-186 : 171

Mallocybe pinicola Saba & Khalid sp. nov.

Figs 2 , 4

Diagnosis.

Most similar to M. siciliana and M. subtomentosa , but differs by the combination of pileal colour, absence of umbo, size of basidiospores, pyriform to broadly clavate, catenate cheilocystidia and an ecological association with Pines. Phylogenetically separated from other species of Mallocybe due to unique ITS and LSU sequences.

Types.

Holotype: PAKISTAN, Prov. Khyber Pakhtunkhwa, Mansehra, Chattar Plain, under Pinus wallichiana , 22 September 2013, leg. M. Saba & A.N. Khalid; MSM#0060, (ISL-F005); GenBank accession nos. OK360954 (ITS), OK392121 (nrLSU). Paratype: Paratype: Pakistan, Prov. Khyber Pakhtunkhwa, Mansehra, Chattar Plain, under Pinus wallichiana , 2 September 2015 leg. M. Saba & A.N. Khalid; MSM#00131(ISL-F006); GenBank accession nos. OK360955 (ITS), OK392122 (nrLSU). Sep 2021, MSM#0200, (ISL-F007); GenBank accession nos. OK360956 (ITS), OK392123 (nrLSU).

Etymology.

Referring to its exclusive association with Pinus .

Description.

Pileus 24.9-27 mm diam., plan with slight depression in centre; margin straight or flaring, not splitting; surface dull, scaly, light orange (5YR8/8) or ochre-yellowish, central disc brownish-orange (5YR5/8). Lamellae adnexed, subdistant, margin eroded, strong brown (5YR4/6) or (5YR4/8). Stipe 31-35.6 mm, central, equal, floccose or pruinose near base, light orange (5YR8/8) or moderate orange (5YR7/8), cortina zone present; annulus absent. Context pale yellow to pale brown, tough, up to 3 mm thick. Odour faint not strong. Taste not recorded.

Basidiospores (6.8-) 7.5-11 × 5-7 µm [x = 9.5 × 6.0 µm, Q = 1.1-1.8], ovoid, ellipsoid or phaseoliform, thin-walled, pale brown or golden brown in KOH. Basidia with yellowish necropigment, 27-42.4 × (5.4-) 8-12 µm, clavate, attenuated below, two to four-spored, thin-walled, hyaline in KOH; sterigmata 2.8-5.6 µm. Pleurocystidia absent. Cheilocystidia 11.8-36.5 × 11-15 µm, hyaline, pyriform to broadly clavate, in chains. Caulocystidia 22-70 × (6.3-) 7.7-14 µm, hyphal, yellowish-brown in KOH with clamp connections at base, thin-walled. Pileipellis hyphae cylindrical, hyaline singly or pale brown in mass in KOH, 5-11.3 µm, thin-walled, pileal hyphal endings 23.6-70 × 7.7-13 µm. Stipitipellis hyphae cylindrical, 5-10 µm, yellowish or olivaceous in KOH. All structures inamyloid. Clamp connections present.

Habitat.

Occurring in September, solitary, scattered on the forest floor in stands of Pinus wallichiana ( Pinaceae ).

Known distribution.

Currently known from Western Himalayas, Pakistan.

Notes.

Mallocybe pinicola is characterised by light orange or ochre-yellowish, medium-sized pileus, absence of umbo, ovoid, ellipsoid or phaseoliform basidiospores, pyriform to broadly clavate, catenate cheilocystidia and its distribution in pine (conifer) forests. Based on the phylogenetic analysis (Fig. 1 ), constructed using the combined dataset of ITS and LSU, M. pinicola clustered with M. siciliana and M. subtomentosa . M. siciliana was originally described from Europe (Italy) by Brugaletta et al. (2017). It is similar to M. siciliana in having similar colour and size of pileus. However, it can be differentiated from M. siciliana by the entire absence of umbo and presence of larger basidiospores ((6.8-) 7.5-11 × 5-7 µm vs. 6.7-9 × 4.4-5.7 µm). Moreover, Mallocybe siciliana is described from forests having Salix species ( S. pedicellata and S. alba ), Platunus orientalis , Tamarix gallica and Hypericum hircium , while M. pinnata has been described from pure pine ( Pinus wallichiana ) forests.

Another closely-related taxa is Mallocybe subtomentosa which was originally described from the United States of America ( Rouse’s Point). It resembles M. pinicola in having the entire absence of umbo, nearly similar spore size and shape of basidiospores (8-10 × 5-6 μm and ellipsoid basidiospores in M. subtomentosa ). However, the presence of dark brown and minutely hairy to tomentose pileus, absence of cystidia and gregarious or subcaespitose habit in M. subtomentosa make the present species distinct from latter ( Massee 1904).

Moreover, phylogenetic analysis (ML and MP), conducted using combined dataset of ITS + LSU, showed the clear separation of our species from these two closely-related taxa and all the sequences of our species clustered together with strong statistical support (99%) forming a monophyletic clade.

Figures

Figure 1. Phylogeny of Mallocybe pakistanica, M. pinicola and related taxa produced from Maximum Likelihood (ML) inference using combined dataset of ITS and nrLSU sequences. Numbers on branches are ML / MP bootstrap values (only ≥ 70). New sequences reported in this study are blue coloured.

Figure 2. Holotypes A Mallocybe pakistanica (MSM # 0061) B Mallocybe pinicola (MSM # 0060). Scale bars: 10 mm (A, B).

Figure 4. Mallocybe pinicola (holotype) A basidia B basidiospores C cheilocystidia D caulocystidia E pileipellis. Scale bars: 10 µm (A); 5 µm (B); 15 µm (C); 20 µm (D, E).