Chroogomphus pruinosus 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 pruinosus M. Kiran & A.N. Khalid sp. nov. Figures 2 , 4

Diagnosis.

Differs from Chroogomphus roseolus by the pileal trama that is inamyloid in Melzer’s reagent and by the presence of pileocystidia and caulocystidia.

Types.

Holotype: Pakistan, Khyber Pakhtunkhwa province, district Upper Dir, Kumrat valley, 35°32'N, 72°13'E, 2400 m a.s.l., solitary or sub-gregarious on moisture rich loamy soil, 20 Aug. 2016, M. Kiran & A.N. Khalid, KM86 (LAH35886), GenBank accession MK509768 (ITS). Paratypes: ibid., KM85 (LAH35888), GenBank accession number MK509769 (ITS); ibid., FS12 (LAH35887), GenBank accession number MK509770 (ITS).

Etymology.

Referring to the pruinose surface of pileus and stipe.

Habitat.

On forest floor under mixed conifers.

Description.

Basidiomata small to medium-sized, Pileus 0.5-3.5 cm in diameter, hemispherical, obtusely conic when young, expanding convex to broadly convex with maturity, margin inrolled initially becoming decurved, surface rough, pruinose, yellowish-orange to reddish-brown (7.5YR8/8-2.5YR4/8). Lamellae decurrent, sub-distant to distant, regular, broad up to 0.5 cm, forked near margin, light yellowish-orange (10YR,8/3), gill margins even, smooth, lamellulae in 2 tiers, alternating with lamellae. Stipe up to 4 cm long, central, pruinose, yellowish-orange to reddish-brown (7.5YR8/8-2.5YR4/8) in colour, rough, with tawny basal mycelium, more or less equal to broader towards base, universal and partial veil absent. Odour and taste not recorded.

Basidiospores [60/3/3], (11-)15-19(-21) × (4-)4.5-8(-8.5) µm, avl × avw = 16.5 × 6.5 µm, Q = (2.2-)2.3-3.4(-3.5), avQ = 2.64 ± 0.43 µm, pale yellow to pale grey-brown in KOH, elongate to somewhat ellipsoid, slightly thick-walled, apiculate, dextrinoid, mostly mono-guttulate, germ pore absent. Basidia 37-53 × 7-13 µm, avl × avw = 41 × 11 µm, hyaline in 5% KOH, clavate, clamped at base, four-spored. Lamellar trama made up of hyphae, 3-6 µm, yellowish in KOH, encrusted, hyphae inamyloid with no or slightly amyloid encrustations, non-dextrenoid. Pleurocystidia 87-112 × 15-23 µm, avl × avw = 93 × 18 µm, hyaline with pale yellow walls in KOH, abundant, encrusted. Cheilocystidia similar to pleurocystidia but slightly smaller. Pileipellis an ixocutis of radially arranged hyphae, 10-12 µm in diameter, yellow to pale brown in KOH, inamyloid, with thin encrusted walls, cylindrical, septate, clamped. Pileocystidia 47-65 × 15-22 µm (avl × avw = 55 × 20 µm), similar to hymenial cystidia, pale yellow to pale brown in KOH. Pileal trama composed of yellowish hyphae with brownish encrustation in KOH, 12-20 µm, inamyloid and non-dextrenoid. Stipitipellis 6-12 µm, pale brown in KOH, inamyloid, straight, cylindrical, smooth and parallel. Caulocystidia 37-111.5 × 7-13.6 µm (avl × avw = 76.5 × 10.25 µm), rare, similar to hymenial cystidia.

Notes.

Chroogomphus pruinosus differs from all other members of the genus in having pileocystidia. This new species is phylogenetically most closely related to C. roseolus , a species that has been reported from China and Pakistan ( Li et al. 2009; Razaq et al. 2016). The macro- and micro-morphology of C. pruinosus is different from C. roseolus in the following characters: C. pruinosus possesses an obtusely conic to broadly convex, yellowish-orange, pruinose, larger pileus; presence of pileocystidia and caulocystidia in C. pruinosus ; and the pileal and lamellar trama and stipitipellis of C. pruinosus are inamyloid, whereas those of C. roseolus are amyloid or partially amyloid ( Li et al. 2009; Razaq et al. 2016). Chroogomphus helveticus is another close relative of C. pruinosus and has also been reported from China and Pakistan ( Li et al. 2009; Razaq et al. 2016). However, no herbarium specimens are available for the Pakistani reports of C. helveticus ( Ahmad et al. 1997) and it is likely that these collections represent C. roseolus , as discussed by Razaq et al. (2016). Chroogomphus roseolus is an Asian native species, whereas reports of C. heleveticus have so far only been confirmed in Europe, generally in association with 5-needle pines - mostly Pinus cembra ( Li et al. 2009), which does not occur in Pakistan. A striking feature of C. helveticus is the presence of a pinkish mycelium at the base of the stipe ( Li et al. 2009; Razaq et al. 2016; Scambler et al. 2018), which is not observed in C. pruinosus . Chroogomphus rutilus and C. purpurascens are morphologically very similar to C. pruinosus . However, C. rutilus has larger basidiomata (20-90 mm) with vinaceous brown or ochraceous-buff to vinaceous red, reddish-brown to purplish, umbonate pileus, buff to yellowish mycelium on the base of the stipe, slightly larger basidiospores (18.0 × 6.2 µm), cylindrical to subfusiform thick walled cystidia and lamellar trama composed of amyloid hyphae ( Singer 1949; Miller 1964; Singer and Kuthan 1976; Gerhardt 1984; Breitenbach and Kränzlin 1991; Villarreal and Heykoop 1996; Horak 2005; Li et al. 2009; Scambler et al. 2018). Chroogomphus purpurascens is distinguished by a grey to brown then purple pileus that is slightly depressed, an ochraceous stipe, salmon to purple pink mycelium on the base of the stipe, thin-walled cystidia and deeply amyloid pileal trama. Moreover, the species is only known to be in association with Pinus cembra , P. koraiensis and P. tabuliformis , three pine species that are not found in Pakistan (Vassiljeva 1950, 1973; Azbukina 1990; Li et al. 2009). Chroogomphus tomentosus , a species that has been reported from Asia ( Li et al. 2009), can be distinguished by its larger basidiospores [15-25 × 6-8(9) µm], thick-walled cystidia (2-4 µm) and strongly amyloid lamellar and pileal trama ( Miller 1964).

Figures

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 4. Line drawings of Chroogomphus pruinosus. A Basidia B Cystidia C Basidiospores D Pileipellis hyphae E Stipitipellis hyphae. Scale bars: 17.5 µm (A), 12 µm (B), 8 µm (C), 26.5 µm (D), 45 µm (E).