Russula viridicinnamomea F. Yuan & Y. Song 2019, sp. nov.
Creators: name: Yuan, Fa
name: Song, Yu
name: Buyck, Bart
name: Li, Jingwei
name: Qiu, Lihong
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Russulales
Russulaceae
Russula
Russula viridicinnamomea

description: Russula viridicinnamomea F. Yuan & Y. Song, sp. nov.   (Figs 2, 3)  
 SYSTEMATIC POSITION. — Basidiomycota, Agaricomycetes, Russulales, Russulaceae, Russula subg. Heterophyllidia subsect. Heterophyllae.   
 HOLOTYPE. — China. Guangdong Province, Zhaoqing City, Dinghu Mountain, on the ground in broad-leaf forest, 14.IX.2015, J. B. Zhang K15091418 (holo-, GDGM [GDGM 75339]).   
ETYMOLOGY. — Referring to the green tinged buff pileus.  
 DIAGNOSIS. — R. viridicinnamomea F. Yuan & Y. Song, sp. nov. is mainly characterized by sequence data for the internal transcribed spacers (ITS), its green tinged cinnamon pileus with undulate and easily peeling margin, absence of lamellulae, basidiospores with partially reticulate ornamentations, gloeocystidia changing to grey in SV and thick pileipellis often with inflated subterminal cells.   
HABITAT AND DISTRIBUTION. — Gregarious in evergreen broadleaf forest.  
 ADDITIONAL SPECIMENS EXAMINED. — China. Guangdong Province, Zhaoqing City, Dinghu Mountain, on the ground in broad-leaf forest, 14.IX.2015, J. B. Zhang K15091418-1, (GDGM[GDGM 75340]).   DESCRIPTION   Basidiomata   
Small to medium sized, agaricoid.   Pileus   
3-5 cm in diam., hemispherical when young, becoming applanate when mature, with entire margin; surface easy to peel to mid-radius, glabrous, dry, not viscid, pale green (#98FB98), with center a very pale greenish-grayish yellow (palegoldenrod, #EEE8AA).   Lamellae   
Adnate, equal, rarely forked, off-white (white smoke, #F5F5F5), unchanging when bruised; edge even, concolorous; lamellulae present, but rare.   Stipe   
3-4.5 × 0.7-1 cm, central, cylindrical, solid; surface dry, off-white (white smoke, #F5F5F5), longitudinally rugulose.   Context   
Off-white (ghost white, #F8F8FF), 1-3 mm thick, unchanging when bruised.   Odour   
Indistinct.   Taste   
Mild.   Spore print   
Whitish.   Basidiospores   
Subglobose to ellipsoid, [80/4/2] (5.1-) 5.3-6.1-7.0 (-8.1) ×(3.6-) 4.2-4.7-5.5 (-5.8)µm, Q = (1.05-) 1.12-1.30-1.47 (-1.68), hyaline in 5% KOH; ornamentations amyloid, composed of verrucose to conical warts up to 0.6 µm, linked by fine lines forming incomplete network, intermixed with isolated warts; suprahilar spot not amyloid.   Basidia   
31-45.5 × 8.5-11.5 µm, clavate to subcylindrical, 4-spored, rarely 2- or 3-spored, some containing oil droplets when young; sterigmata up to 7 µm long.   Lamellar trama   
Composed of nested sphaerocytes surrounded by connective hyphae.   Pleurocystidia   
31.5-66 × 4.5-13.5 µm, abundant, fusoid to cylindrical, with rostrate or mucronate apices, thin-walled, with abundant granular contents, becoming dark grey in sulphovanillin (SV).   Cheilocystidia   
36.5-63 × 4-12 µm, cylindrical, with capitate apex, thinwalled, some with refractive granular contents, becoming dark grey in SV.   Marginal cells   
Not differentiated.   Pileipellis   
Orthochromatic in cresyl blue, divided into an upper trichodermal suprapellis and an underlying subpellis of slender, repent to ascending hyphae. Subpellis 350-450 µm deep, composed of septate, thin-walled, hyaline hyphae. Suprapellis 50-80 µm thick, composed of ascending to erect, densely septate hyphal extremities, often with progressively inflating subterminal cells; terminal cells subcylindrical or more frequently distinctly narrowing upward, with obtuse apices; chains of subterminal cells mostly progressively inflated, with more basal cells mostly ellipsoid to subglobose.   Pileocystidia   
Abundant, mostly 20.5-84 × 3-6 µm, one-celled, terminal on extremities, narrowly clavate to cylindrical in suprapellis, apex rostrate or obtuse, with granular refractive contents, becoming longer and cylindrical in subpellis, without septa and with distinct refractive contents changing to dark grey in SV.   Stipitipellis   
A cutis, orthochromatic in cresyl blue, composed of repent, thin-walled, septate hyphae up to 4.6 µm broad; terminal cells cylindrical.   Caulocystidia   
Frequent, cylindrical, mostly 18.5-54 × 3-13 µm, with obtuse apices, without septa, with refractive contents, turning dark grey in SV.   Stipe trama   
Composed of connective hyphae and nested sphaerocytes.   Clamp connections   
Absent.   Notes   
 The combination of predominantly equal gills, pale spore print, absence of an amyloid suprahilar spot, no primordial hyphae, but presence of single-celled gloeocystidia and welldifferentiated hyphal extremities are all characters that suggest that R. viridicinnamomea F. Yuan & Y. Song, sp. nov. belongs in subg. Heterophyllidia. Our phylogenetic analysis based on ITS sequences placed it firmly within sect. Heterophyllae, subsect. Heterophyllae, where it is closely related to R. bubalina and R. pseudobubalina (Li et al. 2018). The latter subsection was traditionally based on the European R. vesca and R. heterophylla, two species that produce a strong carrot orange reaction to FeSO 4 (which has not yet been verified for our species) and are both unique among European Russulas in possessing thick-walled, needle-shaped cells at the surface of the pileipellis, particularly near the pileus center. Both of these characters have not yet been reported for any of the Chinese species that were recently attributed to this group, except for the confirmed strong reaction to FeSO 4 in R. pseudobubalina and R. subatropurpurea (Li et al. 2018). Whereas the three Chinese species that were recently attributed to this subsection are all similar to R. vesca in general color, viz. mostly in shades of pink to pinkish brown with local discolored spots that are yellowish rusty in color, R. viridicinnamomea F. Yuan & Y. Song, sp. nov. is more reminiscent of R. heterophylla because of the green shades on the pileus.
description: Published as part of Yuan, Fa, Song, Yu, Buyck, Bart, Li, Jingwei & Qiu, Lihong, 2019, Russula viridicinnamomea F. Yuan & Y. Song, sp. nov. and R. pseudocatillus F. Yuan & Y. Song, sp. nov., two new species from southern China, pp. 45-56 in Cryptogamie, Mycologie 20 (4) on pages 47-50, DOI: 10.5252/cryptogamie-mycologie2019v40a4, http://zenodo.org/record/7814877