Russula subatropurpurea, Li & Zheng & Song & Yuan & Qiu, 2019

Li, Jing-Wei, Zheng, Jian-Fei, Song, Yu, Yuan, Fa & Qiu, Li-Hong, 2019, Three novel species of Russula from southern China based on morphological and molecular evidence, Phytotaxa 392 (4), pp. 264-276 : 272-273

Russula subatropurpurea sp. nov. J. W. Li and L. H. Qiu, ( Figs. 5 , 6 )

Mycobank: MB 821922

Etymology: —Refers to its pileus color similar to that of Russula atropurpurea Krombh.

Holotype: —Collected from Dinghu Mountain , Zhaoqing City, Guangdong Province, CHINA, 8 August 2016, J. W. Li and Z. H. Gao K16080818 ( GDGM70634 ).

Basidiomata medium sized. Pileus 4.5–6.8 cm in diam., hemispherical when young, applanate with a depressed center when mature, whole pileus purplish brown (#996633), surface dry, not peeling readily, margin slightly incurved, without striate, cracked with age. Context white, 3–5 mm thick, without color changing when bruised, turning yellow when dry, light purplish red with FeSO 4, taste indistinct. Lamellae white, color unchanged when bruised, crowded, measuring 3–6 mm wide, often forking near margin, without lamellulae. Stipe white to pale white, 3.7–5.5 × 1.2–1.6 cm, cylindrical, slightly narrow towards base. Odorless, whitish spore print.

Spore [60/3/2] globose to ellipsoid, 5.1– 6.2 –7.0 × 4.5– 5.4 –6.2 μm. Q= 1.02– 1.14 –1.34 (1.39), Qm= 1.14 ± 0.10, ornamentation not forming reticulum, composed of amyloid, obtuse warts, measuring 0.38–0.54 μm high, suprahilar area not amyloid. Basidia clavate to subcylindrical, 30.4– 37. 4–41.3 × 7.2– 10.6 –12.9 μm, mostly four-spored, two or three also observed, hyaline, sterigmata 4–7 μm long. Lamellar trama mainly consist of large sphaerocytes. Pleurocystidia 31.3– 47.6 –93.3 × 5.5– 8.8 –10.5 μm, abundant, clavate, slender fusiform to attenuate subcylindrical, most with mucronate to moniliformous or rarely with obtuse apices, with abundant heteromorphous contents and slightly thickened wall, slightly becoming brown in SV. Cheilocystidia clavate to slender subcylindrical, with round obtuse apex, rarely moniliformous or appendiculate, measuring 30.6– 42.1 –71.6 × 6.8– 10.3 –11.6 μm, with abundant refractive contents, also becoming brown in SV. Pileipellis orthochromatic in Cresyl blue, vaguely divided into a 140–180 μm deep suprapellis, of erect or ascending hyphal endings and pileocystidia and a 180–210 μm thick subpellis of horizontally oriented and intricate hyphae. Acicular to subcylindrial, thick walled terminal cells of suprapellis measuring 9.9– 15.0 –23.1 × 3.1– 4.2 –6.1 μm, originating from branched, slightly inflated to subcylindrial subapical cells. Pileocystidia oriented in suprapellis, measuring 17.4– 26.9 –42.5 × 3.4– 4.5 –6.0 μm, one-celled, fusiform or subcylindrical, moniliformous to mucronate-appendiculate, filled with abundant heteromorphous contents, negative to SV. Stipitipellis a cutis measuring 80–120 μm wide, with interwoven hyphae, thin-walled, hyaline, cylindrical. Caulocystidia mostly subcylindrial, clavate also present, with moniliform-appendiculate to round obtuse apex, measuring 21.1– 30.7 –40.7 × 4.3– 4.8 –5.3 μm, Clamp connection absent from all tissues.

Diagnostics: —Purplish brown pileus, mild-tasted and white context changing to light purplish red with FeSO 4, white and forking lamellae without lamellulae, long hymenial cystidia becoming brown in SV.

Habitat and distribution: —Isolated in monsoon evergreen broadleaf forest and pine-broadleaf mixed forest.

Additional specimens examined: — Collected from Dinghu Mountain , Zhaoqing City, Guangdong Province, CHINA, 8 August 2016, J. W. Li and Z. H. Gao K16080816 ( GDGM70633 ) ; 14 July 2017, J. W. Li K17071401 ( GDGM70640 ) .

Figures

FIGURE 5. Russula subatropurpurea. a–b. Scanning Electronic Micrographs of basidiospores; c–f. Photographs of basidiomata (a, c, e. Holotype GDGM70634; b, d, f. Isotype GDGM70633). Scale bars: a–b= 1 μm; c–f= 1 cm.

FIGURE 6. Russula subatropurpurea. (Holotype GDGM70634). a. Basidia; b. Cheilocystidia; c. Pleurocystidia; d. Pileipellis; e. Pileocystidia; f. Caulocystidia. Scale bars= 10 μm.