Lactarius collybioides X.H. Wang

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, Cryptogamie, Mycologie 20 (5), pp. 57-95 : 73-74

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).

Figures

FIG. 9. — Original tree generated by Neighbor-Joining (NJ) phylogenetic analysis, rooted with midpoint. NJ analysis was conducted in MEGA X, using bootstrap method (1000 replicates),p-distance as substitution model,transitions and transversions both included,uniform rates among sites,homogeneous pattern among lineages and pairwise deletion for gaps treatment. The bootstrap proportions higher than 70% are indicated above the nodes. New species are in bold. Sample labels are provided in the order of species name, GenBank accession, and geographical origin. For new species, sample numbers with initials of collectors are provided after GenBank accessions.

FIG. 10. — Basidiocarps:A, Lactarius aurantiobrunneus X.H.Wang,sp.nov.(HKAS 101912,holotype);B, L.exilis X.H.Wang,sp.nov.(HKAS 90043);C, L. collybioides X.H. Wang,sp. nov.(HKAS 76002, holotype);D, L. flaviaquosus X.H. Wang,sp. nov.(HKAS 104207,holotype); E, L. resinosus X.H. Wang,sp. nov.(HKAS 104241).

FIG. 12. — Lactarius collybioides X.H. Wang, sp. nov. (HKAS 76002, holotype): A, basidiospores; B, pleuromacrocystidia; C, lamella edge; D, pileipellis; E, stipitipellis. Scale bars: A, 5 μm; B, 20 μm; C-E, 25 μm.