Xanthagaricus ianthinus Y. Li & F.J. Wang, 2018

Wang, Fengjian, Qi, Liangliang, Zhou, Xiangyu & Li, Yu, 2018, A new species and a new record of Xanthagaricus (Agaricaceae, Agaricales) from China, Phytotaxa 371 (4), pp. 241-250 : 243-247

Xanthagaricus ianthinus Y. Li & F.J. Wang , sp. nov. ( Figs. 2 & 3 )

Fungal names FN570566

Diagnosis:— Xanthagaricus ianthinus differs from Xanthagaricus caeruleus by having a bluish violet pileus and yellowish white to pinkish white lamellulae.

Etymology:—The species epithet “ ianthinus ” refers to the bluish violet pileus of this species.

Type:— CHINA. Hubei Province: Shiyan City, Longquan Temple Tourist Area, 260 m asl, 32°38’13”N, 110°42’13”E, 21 August 2017 (HMJAU45191, Holotype! collected by Fengjian Wang)

Description:— Pileus 3–9 mm diam., initially hemispherical to convex, then plano-convex to nearly applanate with age, bluish violet to violet (15E6–8), more or less violet-brown (15F6–7) at centre, concentrically fibrillosesquamulose, sometimes woolly to matted squamulose on the surface, denser and darker at centre; margin incurved with appendiculate often lacerated white velar remnants; context 0.7 mm thick at the pileus center, elsewhere thinner, no color change when cut or injured. Lamellae free, up to 1.5 mm broad, depressed around the stipe, broadly ventricose, yellowish white (3A2) to light pinkish white (10A2); 1–3 tiers of lamellulae. Stipe 12–24 × 0.8–1.5 mm, equal, central, cylindrical, slightly curved, fistulose, pale yellow (3A3) to slightly grayish yellow (3B3), surface covered with white to whitish squamules or fibrils. Annulus very thin and tiny, superior, fugacious, often absent due to handling or with age. Odor and taste unknown.

Basidiospores [80/4/4] 4.2–4.8(–5.0) × (2.5–)2.9–3.4(–3.6) μm, avl × avw = 4.5 × 3.2 μm, Q = 1.25–1.68, avQ = 1.43, ellipsoid to broadly ellipsoid, smooth under light microscope and SEM, pale yellow to brownish yellow in H 2 O and 5% KOH, without germ-pore, slightly thick-walled (0.5 μm), inamyloid. Basidia 9–17 × 5–8 μm, clavate, pale yellow in H 2 O, hyaline, thin-walled, 4-spored. Lamellar trama regular to subregular, composed of thin-walled cylindrical hyphae 3.5–8.5 μm wide. Cheilocystidia 11–22 × 4.5–9.5 μm, abundant, clavate to broadly clavate, some are slightly fusoid to obovate, smooth, hyaline, thin-walled. Pleurocystidia absent. Pileipellis epithelial, composed of agglutinated globose to subglobose, rarely clavate to ellipsoidal thin-walled cells, terminal cells 7.6–20.7 × 5.4–15.8 μm, slightly encrusted, with some vacuolar yellowish brown pigments when observed in KOH or H 2 O. Caulocystidia 20–55 × 3–5 μm, hyaline, varying in shape from clavate to cylindrical. Stipititrama composed of parallel hyphae 3–10 μm wide, yellowish brown in mass but pale yellow or subhyaline individually. Clamp connections absent in all tissues.

Habit, habitat and distribution:—In small groups, saprotrophic on soil of broadleaf forest or conifer-broadleaf forest, fruiting during August–September. It is so far only known from Hubei Province of China.

Additional specimens examined:— CHINA. Hubei Province: Shiyan city, Longquan temple tourist area, in broad-leaved forests, 252 m asl, 32°38’13”N, 110°42’24”E, 7 September 2017, Fengjian Wang 2756 ( HMJAU45192 !) ; same location, in broad-leaved forests, 253 m asl, 32°38’13”N, 110°42’12”E, 7 September 2017, Fengjian Wang 2759 ( HMJAU45193 !) ; same location, in conifer-broadleaf forests, 293 m asl, 32°38’14”N, 110°42’13”E, 28 September 2017, Fengjian Wang 2816 ( HMJAU45194 !) .

Xanthagaricus epipastus (Berk. & Broome) Hussain (2018: 123) , Turk J Bot. 42:123–133 (2018) ( Figs. 4 & 5 ) Description:— Pileus 4–14 mm diam., conical to broadly conical or convex, orange-yellow (2A4–7) to vivid yellow (2A8), darker on the disc; with yellow (3A4) to yellowish brown (5D 8, 5E 8) squamulose on the surface, more concentrated and darker at centre; margin deflexed with appendiculate velar remnants, concolorous with the pileus squamules. Lamellae free, crowded, up to 1.5 mm broad, ventricose, pink white (10A2) to brownish pink (6C3, 6D3); lamellulae in 1–3 tiers. Stipe 8–38 × 0.5–1.0 mm, yellow to yellow brown, central, cylindrical, equal, hollow; surface covered with some scattered squamules. Annulus very thin and tiny, superior, fugacious. Pileus context 0.5 mm thick at pileus centre, yellowish white, unchanged when bruised or cut. Odor not distinctive.

Basidiospores [60/3/3] (4.0–)4.2–4.9(–5.2) × (2.5–)2.8–3.4(–3.5) μm, Q = 1.31–1.65, avl × avw = 4.6 × 3.1 μm, avQ = 1.47, ellipsoid, without germ-pore, inamyloid, yellow to brownish yellow. Basidia 9.0–15.9 × 4.4–6.3 μm, 4- spored, cylindrical to broadly clavate. Cheilocystidia 10.7–23.4 × 5.2–11.5 μm, smooth, mostly broadly clavate, some obpyriform, some subcapitate. Pleurocystidia absent. Pileipellis epithelial, composed of chain of spherical to ovoid cells, rarely clavate to ellipsoidal cells, terminal cells 8.4–28.8 × 7.5–15.8 μm, slightly encrusted, with some vacuolar pigments when observed in KOH or H 2 O. Annulus composed of hyphae 5–8 μm diam., hyaline, smooth, terminal cells inflated 13–22 × 7–8 μm. Stipitipellis hyphae 4–10 μm, smooth, hyaline.

Habit, habitat and distribution:—In small groups, scattered on the ground of broadleaf forest or conifer-broadleaf forest; known from Sri Lanka, Thailand, and now China.

Specimens examined:— CHINA. Hubei Province: Shiyan city, Longquan temple tourist area, in broad-leaved forests, 252 m asl, 32°38’13”N, 110°42’24”E, 19 September 2017, Fengjian Wang 2811 ( HMJAU45195 ) ; same location, in broad-leaved forests, 278 m asl, 32°38’14”N, 110°42’11”E, 28 September 2017, Fengjian Wang 2825 ( HMJAU45196 ). Hanjiang Normal University in conifer-broadleaf forests, 355 m asl, 32°37’6”N, 110°46’59”E, 5 October 2017, Fengjian Wang 2835 ( HMJAU45197 ) .

Figures

FIGURE 2. Basidiomata of Xanthagaricus ianthinus and SEM of basidiospores. a. Stipe showing thin, tiny and fugacious annulus (HMJAU45191, holotype). b. Lamellae showing color variation yellowish white to light pinkihs white (HMJAU45194). c. Pileus showing residual white veil (HMJAU45193). d. Basidiospores appearing smooth under SEM (from HMJAU45191). Scale bars: a, c = 2 mm; b = 5 mm; d = 5 μm. Photos by F.J. Wang.

FIGURE 3. Microscopic features of Xanthagaricus ianthinus (HMJAU45191, holotype). a. Basidiospores. b. Cheilocystidia. c. Epithelial pileipellis with encrusted wall. d. Basidia. e. Caulocystidia. Scale bars: a = 5 μm, b–e = 10 μm. Drawings by F.J. Wang.

FIGURE 4. Basidiomata of Xanthagaricus epipastus (a–c from HMJAU45195, d from HMJAU45197). a. Basidiomata.b. Pileus showing yellowish brown squamulose and gills showing color deepens after maturing. c. Stipe showing thin, tiny and fugacious annulus. d. Basidiomata showing their habitat. Scale bars: a, d = 3 mm; b, c = 5 mm. Photos by F.J. Wang.

FIGURE 5. Microscopic features of Xanthagaricus epipastus (HMJAU45195). a. Basidiospores. b. Epithelial pileipellis with encrusted wall. c. Cheilocystidia. d. Basidia. Scale bars: a = 5 μm, b–d = 10 μm. Drawings by F.J. Wang.