Lactarius collybioide, sp. nov.
Creators: name: Wang, Xiang-Hua
name: Das, Kanad
name: Bera, Ishika
name: Chen, Yu-Hui
name: Bhatt, Rajendra Prasad
name: Ghosh, Aniket
name: Hembrom, Manoj Emanuel
name: Hofstetter, Valérie
name: Parihar, Arvind
name: Vizzini, Alfredo
name: Xu, Tai-Min
name: Zhao, Chang-Lin
Publisher: name: Zenodo
Year: 2019
Subjects: Biodiversity
Taxonomy
Fungi
Basidiomycota
Agaricomycetes
Russulales
Russulaceae
Lactarius
Lactarius collybioide

description: 84. Lactarius collybioides X.H. Wang, sp. nov.
(Figs 9; 10C; 12)
A small slender species characterized by very pale fruiting bodies with a collybioid habit, ellipsoid spores with nearly isolated conical warts, pileipellis an (ixo)hymeno-hyphoepithelium and emergent pleuromacrocystidia.
TYPUS. — China. Yunnan Prov., Puer, road from Ninger to Puer, 1500 m a.s.l., in fagaceous forest, 5.VII.2012, coll. X.H. Wang, no. 3444 (holo-, KUN [HKAS 76002]!).
MYCOBANK. — MB 829279.
GENBANK. — MK351969, MK351970 (ITS).
ETYMOLOGY. — Referring to the small slender fruiting bodies with a collybioid habit.
ADDITIONAL SPECIMENS EXAMINED. — China. Guangdong Prov., Fengkai Co., Heishiding nature reserve, 5.VIII.2012, coll. F. Li, no. 819a (KUN[HKAS 77710]). — Yunnan Prov.: Puer, Hongqi reservoir, 450 m a.s.l., 3.VIII.1991, coll. Z.L. Yang, no. 1380 (KUN[HKAS 24649]); Xishuangbanna, Jinghong, Dadugang, under fagaceous trees, 31.VIII.2004, coll. X.H. Wang, no. 1807 (KUN[HKAS 47727]).
HABIT, HABITAT AND DISTRIBUTION. — In group, growing on humus, under fagaceous trees. South (Guangdong Prov.) and tropical southwestern (Yunnan Prov.) China.
DESCRIPTION
Basidiomata
Small, slender.
Pileus
10-20 mm in diameter, at first concave with a slightly decurved margin, soon fully concave to shallowly infundibuliform, 1/2 to 2/3 of the radius transparently striate; surface nearly dry, hygrophanous, pale yellow when young, remaining so or pale yellow to pale orange in age.
Context
0.5-1.5 mm thick, pale cream-colored.
Lamellae
1-1.5 mm broad, medium crowded, broadly adnate to decurrent, pale yellow to pale orange when young, grayish orange when fully mature.
Stipe
20-35 × 1-3 mm, cylindrical, equal or slightly enlarged downward, hollow; surface nearly smooth, hygrophanous, concolorous with the pileus or brownish orange.
Latex
Watery, not changing or staining, acrid.
Spore print
Not obtained.
Basidiospores
(140/7/4) 5.5-6.3-7.0 (7.5) × 4.5-5.2-6.0 Μm [Q = (1.09) 1.13-1.32 (1.43), Q = 1.22 ± 0.06] [holotype (40/2/1) (5.5) 6.0-6.4-7.0 (7.5) × 4.5-5.2-6.0 Μm, Q = 1.09-1.34 (1.43), Q = 1.24 ± 0.08], ellipsoid, rarely broadly ellipsoid; ornamentation 0.6-1.0 (1.3) Μm high, of isolated conical warts, a few of them fused or connected by fine lines; plage distally amyloid.
Basidia
4-spored, 25-40 × 7-12 Μm, clavate, rarely cylindrical.
Pleuromacrocystidia
Rare to common, more common at the lower side of the cap between the lamellae, often emergent, projecting up to 50 Μm beyond the basidia layer, (34) 50-85 × 7-12 Μm, fusiform, sublanceolate, sharply pointed, some with a moniliform apex, with dense yellowish granular or crystalline contents.
Hymenophoral pseudocystidia
Uncommon, 3-4 Μm broad.
Lamella edge
Sterile or fertile; cheilomacrocystidia rare to common, similar to pleuromacrocystidia in shape but smaller.
Pileipellis
An ixo-hymenoepithelium or ixo-hymenoepithelium with a sparse slimy layer, 30-50 Μm thick; terminal cells of suprapellis (7) 10-35 × 4-12 (17) Μm, ellipsoid, clavate, cylindrical; cells of subpellis 10-40 × 10-20 Μm, globose, ellipsoid, pyriform, rarely hyphoid, slightly gelatinized.
Stipitipellis
An (ixo)cutis; 15-30 Μm thick; hyphae closely packed, 2-4 Μm broad, rarely slightly thick-walled, terminal cells 15-50 × 3-5 Μm, with a blunt apex, slightly gelatinized.
Lactifers
Rare to common, robust, nearly colorless.
Pileus and stipe trama
With numerous rosettes.
NOTES
This species is distinctive in L. subg. Russularia because of its pileipellis a hymenoepithelium with a slimy layer and spores with isolated warts. In L. subg. Russularia, ornamentation of isolated warts have been found in the following species: Chinese L. flaviaquosus X.H. Wang, sp. nov. (described below), L. minimus var. macrosporus Z.S. Bi & G.Y. Zheng (Bi et al. 1985), L. tuberculatus X.H. Wang (Wang 2018), L. verrucosporus G.S. Wang & L.H. Qiu (Wang et al. 2018b); L. liliputianus Verbeken & E. Horak from Papua New Guinea (Verbeken & Horak 2000); North American L. highlandensis Hesler & A.H. Sm. and L. rimosellus Peck (Hesler & Smith 1979); European L. camphoratus (Bull.) Fr. (Heilmann-Clausen et al. 1998; Basso 1999). Lactarius minimus var. macrosporus does not have macrocystidia and its pileipellis lacks a slimy layer (Wang 2007). The spores are more round in L. minimus var. macrosporus and L. verrucosporus and spore warts of L. liliputianus and L. verrucosporus often have a truncate apex. In the two North American species, the pilei are areolate-rimose when mature and macrocystidia are absent. Lactarius camphoratus and L. tuberculatus have bigger fruiting bodies and their spore ornamentations are less isolated. Indian L. atrii Van de Putte & K. Das has a slimy layer in the pileipellis. The spore warts of this species are blunt and the pileipellis lacks isodiametric cells (an ixocutis) (Wisitrassameewong et al. 2016).
description: Published as part of Wang, Xiang-Hua, Das, Kanad, Bera, Ishika, Chen, Yu-Hui, Bhatt, Rajendra Prasad, Ghosh, Aniket, Hembrom, Manoj Emanuel, Hofstetter, Valérie, Parihar, Arvind, Vizzini, Alfredo, Xu, Tai-Min & Zhao, Chang-Lin, 2019, Fungal Biodiversity Profiles 81 - 90, pp. 57-95 in Cryptogamie, Mycologie 20 (5) on pages 73-74, DOI: 10.5252/cryptogamie-mycologie2019v40a5, http://zenodo.org/record/7814899