Boletinellus viridianus Salna Nanu & T.K.A. Kumar, 2023

Nanu, Salna & Arun Kumar, T. K., 2023, A new species of Boletinellus (Boletinellaceae, Boletales) from India, Phytotaxa 594 (3), pp. 223-231 : 227-229

Boletinellus viridianus Salna Nanu & T.K.A. Kumar , sp. nov.,

Figs. 2–3

MycoBank:—MB846744

Etymology:—“ viridianus ” refers to the bluish green color change of the tissues after bruising.

Diagnosis:—This species differs from all other species of Boletinellus by its pale yellowish pileal context immediately turning bluish green; stipe surface covered with poroid-lamellate hymenophore extending throughout the stipe; oblong to ellipsoid, small, inamyloid basidiospores, 6.5–7.5 × 5–5.5 µm (Q = 1.2–1.4, Qm = 1.29), a cutis type of pileipellis with intermittent trichodermal clusters of filamentous hyphae.

Holotype:— INDIA. Kerala State, Palakkad district, Parambikkulam, 5 June 2022, Salna Nanu ( ZGCSN163 ). GenBank accession numbers: 28 S = OP526842 , ITS = OP542551 .

Description:— Basidiomata medium-sized. Pileus 40–100 mm diam., convex when young becoming nearly applanate at maturity, slightly depressed at center with age; margin incurved to nearly undulate; surface glabrous or sub-velutinous, becoming viscid when wet, brownish to yellowish brown, sometimes with grayish brown or dark brownish tinge. Context thick, 10–25 mm, pale yellowish, immediately turning bluish green on bruising. Hymenophore deeply decurrent, poroid-lamellate, lamellae connected with many cross-veins; pores 3–5 mm wide, angular, elongate towards the margin, yellowish, pale yellow towards the margin, becoming brownish yellow with age, turning bluish green immediately on bruising; tubes up to 3 mm long, yellowish, turning bluish green when cut. Stipe 30–60 × 8–30 cm, eccentric to lateral, subcylindrical, enlarging towards the base; surface covered with poroid-lamellate hymenophore extending to the stipe base, denser towards the center, sparse at the base; surface pale yellowish in the central part, off white to yellowish in the lower and upper parts, changing bluish green immediately on bruising. Context thick, firm, pale yellowish, with pinkish or reddish brown tinges, turning blue slowly on exposure.

Basidiospores 6.5–7.5 × 5–5.5 µm [Q = (1.2–1.4, Qm = 1.29], oblong to ellipsoid, with a large oil drop, yellowish in water, thin- to thick-walled (up to 1 µm), inamyloid. Basidia 26–36 × 6–10 µm, narrowly clavate to clavate, 4- spored, rarely 2-spored, thin-walled, hyaline to pale yellow in water; sterigmata up to 5 µm long. Pleurocystidia 21–35 × 4–9 µm, rare, subfusiform or flexuose, sometimes with a secondary septum, most with attenuated apex, thin-walled, hyaline to pale yellow in water. Cheilocystidia similar to pleurocystidia in size and shape, rare. Hymenophoral trama divergent, sometime with swollen hyphae; hyphae 3.5–21 µm wide, thin-walled, hyaline to pale yellow in water. Pileipellis a cutis with trichodermal patches of filamentous hyphae, 3–7 µm wide, thin-walled, pale yellowish in water; pileal trama consisting of interwoven hyphae, 3–8 µm wide, thin-walled. Stipitipellis a cutis disrupted by patches of hymenophoral structures, caulobasidia similar to hymenial basidia in shape and size. Clamp connections present in all tissues. Odor and taste not observed. Spore print not obtained.

Habitat: On soil. Scattered under Terminalia species.

Additional specimen examined: INDIA. Kerala State, Palakkad district, Parambikkulam , 6 June 2022, Salna Nanu ( ZGCSN186 ) .

Figures

FIGURE 2. Boletinellus viridianus (ZGCSN163, holotype). A–C. Fresh specimens in habitat; D. Bluing stipe on bruising. Scale bar = 2 cm. Photos by: Salna Nanu.

FIGURE 3. Boletinellus viridianus (ZGCSN163, holotype). A. Basidiospores; B. Basidia; C. Cheilocystidium; D–F. Pleurocystidia; G. Pileipellis; H. Stipitipellis. Scale bars: A–F = 10 μm, G–H = 20 μm. Photos by: Salna Nanu.