Chroogomphus pakistanicus M. Kiran & A.N. Khalid, 2020

Kiran, Munazza, Sattar, Ammara, Zamir, Khushbakht, Haelewaters, Danny & Khalid, Abdul Nasir, 2020, Additions to the genus Chroogomphus (Boletales, Gomphidiaceae) from Pakistan, MycoKeys 66, pp. 23-38 : 23

Chroogomphus pakistanicus M. Kiran & A.N. Khalid sp. nov. Figures 2 , 3

Diagnosis.

Differs from Chroogomphus filiformis by the pileus ranging in colour from greyish-yellow brown to dark bluish-grey to orange and by the absence of a pinkish mycelium at the base of the stipe.

Types.

Holotype: Pakistan, Khyber Pakhtunkhwa province, district Dir (Upper), Kumrat valley, 35°32'N, 72°13'E, 2400 m a.s.l., gregarious on forest floor, 20 Aug 2016, M. Kiran & A.N. Khalid, KM82 (LAH35889), GenBank accession number MK509771 (ITS). Paratype: ibid., KM83 (LAH35890), GenBank accession number MK509772 (ITS).

Etymology.

Referring to the country where the type collections were collected.

Habitat.

On forest floor under mixed conifers.

Description.

Basidiomata small to medium-sized. Pileus 2-5 cm in diameter, secotioid when young, expanding broadly-parabolic to hemispherical towards maturity, radially fibrillose, ranging in colour from greyish-yellow brown (2.5Y,5/2) to dark bluish-grey (5BG,4/1) to orange (5YR,6/6), surface shiny or glistening, smooth, margin inrolled initially becoming straight to slightly seriate when mature. Lamellae adnate to slightly decurrent, distant, regular, concolorous to pileus, smooth, entire, lamellulae in two tiers, alternating with lamellae, short. Stipe 3-5.5 × 1 cm, central, more or less equal or sometimes enlarged at base, orange (5YR7/8) to reddish-brown (2.5YR4/8), pruinose to fibrillose to squamulose, with pinkish-white mycelium at stipe base, universal and partial veil absent. Odour and taste not recorded.

Basidiospores [60/3/2], (15-)16-19.5(-20.5) × (5.5-)6-7.5(-8) µm, avl × avw = 17.5 × 6.6 µm, Q = (2.1-)2.2-3(-3.5) µm, avQ = 2.56 ± 0.33 µm, oblong to elongate, mono-guttulate to multi-guttulate, pale brown in KOH, apiculus prominent, smooth, dextrinoid. Basidia 30-50 × 8-10.5 µm, avl × avw = 40 × 9 µm, hyaline to pale yellow in KOH, clavate to club-shaped. Lamellar trama yellowish hyphae in KOH, 5-11 µm, with brownish encrustations, inamyloid and non-dextrenoid. Pleurocystidia 75-107 × 17.5-25.5 µm, avl × avw = 91 × 43 µm, clavate to sometimes slightly utriform, pale brown to brown in KOH, encrusted, inamyloid. Cheilocystidia similar to pleurocystidia. Pileipellis a cutis, pale yellow to brownish KOH, 4-6 µm wide, amyloid, septate, clamped. Pileal trama composed of amyloid encrusted hyphae, 4-18 µm, yellowish in KOH. Stipitipellis a cutis of 3-9.5 µm wide, pale yellow to pale brown KOH, cylindrical, parallel, septate amyloid hyphae present at the base. Clamp connection present in all tissues.

Notes.

Chroogomphus pakistanicus can be easily distinguished from the other members in the genus by the unique bluish-grey colour of its pileus. The phylogenetically closest relative, C. filiformis , (Figure 1 ) is discriminated from C. pakistanicus based on the following morphological features: (1) the pileus of C. pakistanicus ranges in colour from greyish-yellow brown to dark bluish-grey to orange and has a glistening surface, whereas in C. filiformis the pileus is clearly olive grey to pinkish-orange; and (2) the pinkish mycelium at the base of the stipe typical for C. filiformis ( Li et al. 2009) is absent in C. pakistanicus . Chroogomphus britannicus was included in sect. Filiformes by Scambler et al. (2018). In our phylogenetic tree, its position is unresolved within subg. Chroogomphus . Morphologically, it can be easily distinguished from the new species. Chroogomphus britannicus has larger basidiospores (20.3 × 7.1 µm), amyloid lamellar trama and inamyloid pileal trama ( Scambler et al. 2018). The morphology of Chroogomphus pakistanicus is similar to C. mediterraneus , which can be distinguished by a subconical to convex pileus ranging in colour from grey to olivaceous to brown to red to pink to purplish, in combination with differently shaped cystidia, ranging from cylindrical, subfusiform, subutriform to sometimes subcapitate ( Scambler et al. 2018). Chroogomphus vinicolor is another species related to C. pakistanicus , but the cystidia of C. vinicolor are thick-walled (5-7.5 µm) and it has a differently coloured pileus ( Miller 1964; Singer and Kuthan 1976). Furthermore, geographically, members of the section Vinicolores have thus far only been reported from North America (Scambler at al. 2018). Chroogomphus jamaicensis may also be confused with C. pakistanicus , but it can be separated from the latter in having different micromorphological characters including thick-walled (4-5 µm) fusiform caulocystidia, which are occasionally amyloid towards the base ( Miller 1964).

Figures

Figure 1. The best-scoring ML tree (- lnL = 4385.926) of the genus Chroogomphus, reconstructed from the ITS dataset. ML bootstraps (> 70 %) and posterior probabilities (> 0.75) are indicated above or in front of the branch leading to each node. Newly described species are in boldface.

Figure 2. Basidiomata of Chroogomphus spp. A-E Chroogomphus pakistanicus A, B LAH 35889, holotype C-E LAH 35890 F-K Chroogomphus pruinosus F, G LAH 35887 H, I LAH 35888; J, K LAH 35886, holotype. Scale bars: 1 cm.

Figure 3. Line drawings of Chroogomphus pakistanicus. A Basidia B Cystidia C Basidiospores D Pileipellis hyphae E Stipitipellis hyphae. Scale bars: 12 µm (A), 17.5 µm (B), 8.5 µm (C), 25 µm (D), 30 µm (E).