Lactarius flaviaquosus X.H. Wang, 2019

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 : 76-77

86. Lactarius flaviaquosus X.H. Wang , sp. nov.

( Figs 9 ; 10D ; 14 )

A medium-sized species with faintly zonate pileus, latex yellow or white changing to yellow and watery instantly, rarely white or watery, ellipsoid spores with isolated conical warts and pileipellis an (ixo-)lattice

TYPUS. — China. Yunnan Prov., Maguan Co., Dalishu, Adushangba , 27°03’3.28’’N, 104°08’18.52’’E, 1800 m a.s.l., in fagaceous forest, 13.X.2017, coll. X.H. Wang, no. 4734 (holo-, KUN [ HKAS 104207 ]!).

MYCOBANK. — MB 829289.

GENBANK. — MK351937 - MK351941 (ITS).

ETYMOLOGY. — Flavi- = yellow, -aquosus = water, referring to the yellow latex or white then changing to yellow and watery.

ADDITIONAL SPECIMENS EXAMINED. — China. Yunnan Prov.: Baoshan, Gaoligong Mts. nature reserve, old road from Baoshan to Tengchong, 20 km to Bawan, 17.VII.2003, coll. X.H. Wang, no. 1553 (KUN[HKAS 43947]); Lüchun Co., Huanglian Mt. nature reserve, near Huanglianshan reservoir, 8.VII.2012, coll. X.H. Wang, no. 3523 (KUN[HKAS 76060]); Maguan Co., Gulinqing, 2000 m a.s.l., 29.VI.1992, coll. Z.L. Yang, no. 1821 (KUN[HKAS 25946]); Malipo Co., Laojun Mt. nature reserve, 1500 m a.s.l., 23.VI.1992, coll. Z.L. Yang, no. 1763 (KUN[HKAS 25950]); ibid, 24.VI.1992, coll. Z.L. Yang, no. 1794 (KUN[HKAS 25951]); Pingbian Co., Dawei Mt. nature reserve, 1800-2100 m a.s.l., 4.VII.1992, coll. Z.L. Yang, no. 1877 (KUN[HKAS 25947]); ibid, 4.VII.1992, coll. P.G. Liu, no. 1280 (KUN[HKAS 25948]); Pingbian Co., near the county town, 1500 m a.s.l., 21.VII.2005, coll. X.H. Wang, no. 1934 (KUN[HKAS 49562]); Zhenyuan Co., 313 provincial road (from Zhenyuan to Mengda), 4.VII.2012, coll. X.H. Wang, no. 3431 (KUN[HKAS 75992]). — Taiwan Prov.: Ilan Co., Fushan Botanical Garden, 600 m a.s.l., 20.IV.1993, coll. W.N. Chou, no. CWN-TF615 (TNM[F0023042]); Nantou Co., Hsinyi, Tachieshan, 13.IV.1995, coll. W.N. Chou, no. CWN00783 (TNM[F0003237]); Nantou Co., Yuchih Hsiang, Lienhuachih, 22.IV.2006, coll. W.N. Chou, no. CWN07078 (TNM[F0027273]).

HABIT, HABITAT AND DISTRIBUTION. — 1-4 individuals growing together, in fagaceous forest. Southwestern (Yunnan Prov.) and southeastern ( Taiwan and Zhejiang Provinces) China ( Gao et al. 2013; GenBank accession JQ991751 ).

DESCRIPTION

Basidiomata

Small to medium-sized.

Pileus

20-50 mm in diam., depressed with an expanded margin, with age often translucently striate at margin; surface smooth, slightly viscid when wet, yellowish brown, reddish brown, brownish orange, darker at center, faintly zonate.

Context

1 mm thick, pale brown.

Lamellae

2-3 mm broad, straight to short decurrent, crowded, concolorous with pileus.

Stipe

20-70 × 3-7 (10) mm, cylindrical, equal, solid then hollow; surface smooth, dry, concolorous with pileus or with more reddish tinge, light brown, often strigose at the base.

Latex

Yellow or white changing to yellow watery instantly, rarely white or watery and unchanging, acrid, sharp.

Spore print

not obtained.

Basidiospores

(340/17/10) (6.0) 6.5-7.4-8.5 (9.5) × (5.0) 5.5-5.9-6.5 (7.5) Μm [Q = (1.09) 1.17-1.36 (1.43), Q = 1.26 ± 0.06] [holotype (40/2/1) (6.5) 7.0-7.4-8.0 (8.5) × (5.0) 5.5-5.8- 6.5 Μm, Q = (1.17) 1.21-1.38 (1.43), Q = 1.28 ± 0.06], ellipsoid, rarely broadly ellipsoid; ornamentation 0.6-1.3 (1.5) Μm high, of isolated conical warts, few of them fused or connected by fine lines; plage distally amyloid or inamyloid.

Basidia

4-spored, 30-45 × 8-13 Μm, clavate.

Pleuromacrocystidia

Uncommon to numerous, emergent, projecting up to 30 Μm beyond the basidia layer, originating from subhymenium or hymenophoral trama, (40) 50-100 (120) × 7-12 (15) Μm, subfusiform, sublanceolate, rarely subcylindrical, with a sharp apex, with dense yellowish granular or crystalline contents.

Lamella edge

Fertile with few basidia; cheilomacrocystidia common to numerous, 20-60 × 5-9 Μm, fusiform, subcylindrical, apex often moniliform or with apical appendices, with strongly refractive granular, crystalline or agglomerated contents; marginal cells 7-30 × 4-10 Μm, clavate, cylindrical.

Hymenophoral pseudocystidia

Rare to common, 2-3 Μm broad, rarely forking, with refractive contents.

Pileipellis

An (ixo)cutis or (ixo)lattice, 50-170 Μm thick; hyphae (3) 4-10 (12) Μm broad, terminal cells 15-65 × 3-6 Μm, with a blunt apex, some shrivelled, hyphae in subpellis gelatinized, colorless to pale yellow, some slightly thick-walled (0.5 Μm).

Stipitipellis

A cutis, 30-60 Μm thick; hyphae closely packed, 3-6 Μm broad, with a blunt apex, gelatinized, slightly thick-walled, nearly colorless.

Lactifers

Numerous, in hymenophoral trama nearly colorless to pale yellowish brown, in pileus and stipe trama robust, pale to golden yellowish brown.

Pileus and stipe trama

With numerous rosettes.

NOTES

The holotype has white milk that changed yellow instantly, whereas ZLY1763, 1794, 1821, 1877 and XHW3431 have yellow milk. The milk of XHW3525 is watery and unchanging. The holotype, XHW3431, and XHW3525 are sequenced and they have nearly identical ITS sequences ( Fig. 9 ). As the latex of this species seems variable, three specimens with the same microscopical characters but whitish milk (XHW1553, XHW1934 and PGL1280) are here also identified to belong to the same species. The ellipsoid spores with isolated warts and the pileipellis an ixocutis-lattice with inflated hyphae are good specific characters. Indian L. atrii seems to be similar, but has bigger spores with blunt warts and azonate pileus. Thai L. aquosus H.T. Le & K.D. Hyde , a species showing affinity to this new species in the ITS phylogeny, has unchanging watery latex, reticulate spores and much broader hyphae in the pileipellis ( Wisitrassameewong et al. 2015). Two species of L. subg. Russularia with yellowing latex are reported from subalpine southwestern China ( Wisitrassameewong et al. 2016). They both have azonate pileus and more connected spore ornamenta - tion. For notes on species with isolated warts, see under L. collybioides .

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. 14. — Lactarius flaviaquosus X.H. Wang, sp. nov. (HKAS 104207, holotype): A, basidiospores; B, pleuromacrocystidia; C, lamella edge; D, pileipellis. Scale bars: A, 5 μm; B, 20 μm; C, D, 25 μm.