Lactifluus lorenae Montoya, Caro, Ramos & Bandala

Montoya, Leticia, Caro, Abraham, Ramos, Antero & Bandala 1, Victor M., 2019, Two new species of Lactifluus (Fungi, Russulales) from tropical Quercus forest in eastern Mexico, MycoKeys 59, pp. 27-45 : 27

Lactifluus lorenae Montoya, Caro, Ramos & Bandala sp. nov. Figs 2a, b , 3 , 5a, b

Holotype.

MEXICO, Veracruz State, Alto Lucero Co., 12 km SW Palma Sola (road Veracruz-Nautla) 25 June 2015, Montoya 5190 (XAL). Ectomycorrhizal, under Quercus oleoides .

Diagnosis.

Lactifluus lorenae is clearly distinguished by white basidiomes, staining orange-brown, latex staining white paper yellow, odour somewhat chlorine-like, basidiospores broadly ellipsoid, pleuromacrocystidia 40-53 × 7-9 µm and pileipellis a hyphoepithelium with a gelatinzied hyphoid layer, 30-60 µm wide.

Gene sequences ex-holotype.

MK211185 (ITS), MK211194 (LSU), MK258872 (rpb 2).

Etymology.

In honour of Dr. Lorena E. Sánchez Higueredo because of her interest in the conservation of tropical oak forest relicts in Veracruz, Mexico.

Pileus 25-114 mm diam., convex when young, expanded to broadly infundibuliform, undulate, depressed at centre when old, smooth to irregular when old, dull whitish with yellow tinges (3A2-3A5), staining orange-brown (5C6-C7) when bruised; margin decurved when young, with edge faintly decurved to straight when old, continuous to irregular. Lamellae adnate to subdecurrent, crowded to very close, 0.5-1.8 mm broad, edge entire, bifurcate at different levels, yellowish (3-4A2), staining orange-brown when handled, with lamelullae of different sizes, approximately 1 lamelullae per two lamellae. Stipe 20-90 × 11-35 mm, eccentric, cylindrical, attenuated or broadened towards the base, robust but at times flattened; surface smooth to irregular, faintly velvety under lens, more evident towards the base, whitish to cream-white, with yellow stains (5Y8/6), staining orange-brown when handled. Context cream colour, changing to brownish-orange when exposed, compact. Odour somewhat like chlorine; taste acrid. Latex whitish, milky, at times somewhat serous, staining white paper yellow (5Y 8/2), brownish after some minutes; taste burning acrid. KOH staining the pileus and stipe yellow to pale reddish.

Basidiospores (6 –)6.5–8(– 10) × (5 –)5.5–6.5(– 9) µm; X̄ = 7.0 –7.3(– 9.2) × 5.5 –6.0(– 7.6) µm; Q̄ = 1.20-1.27, broadly ellipsoid, thin-walled; ornamentation 0.2-0.4 µm high (measured under SEM), an incomplete reticulum, composed of thick and thin bands and some isolated warts, others ornamented almost with isolated warts and some unconnected bands, plage inamyloid; under SEM the relief of the bands of the basidiospores ornamentation appear with an irregular inflated shape and the plage area with reminiscences of ornamentation. Basidia 30-45 × 8-11 µm, clavate, some subcylindrical, with refractive contents, thin-walled, with 2, 4 or at times 3 sterigmata. Pleuromacrocystidia 40-53 × 7-9 µm, clavate, some cylindrical and faintly broadened towards the middle area, thin-walled, with refractive needle-like and granular contents. Cheilomacrocystidia 34-54 × 7-9 µm, cylindrical, some clavate at base, thin-walled, with refractive contents. Pseudocystidia absent. Pileipellis a hyphoepithelium; suprapellis layer of 30-60 µm thick, gelatinized, composed of periclinally orientated hyphae, in some areas the hyphae are loosely intermixed or at times projected in mounds of up to 85 µm thick, the gelatinized matrix dissolved in KOH after some minutes; hyphae 2-4 µm broad, cylindrical, septate, wall up to 0.5 µm thick, sinuous; subpellis of 50-130 µm thick, composed of subisodiametric cells, 12-35 × 10-38 µm diam., yellowish in KOH, wall up to 1.0 µm thick; dermatocystidia 37-128 × 6-8 µm, 3.6-4.8 µm diam. at base, clavate, with refractive needle-like and granular contents, wall up to 0.5 µm thick, scarce, arising from subisodiametric cells of the subpellis layer. Context hyphae 5-7 µm broad, cylindrical, thin-walled, some with walls 0.5 µm thick, with faint refractive contents, sphaerocytes 12-26 µm diam., pale yellowish, wall 0.5(-1) µm thick, frequent, laticiferous hyphae 4-7 µm diam., infrequent. Hymenophoral trama composed of hyphae which are 4-6 µm diam., septate, wall 0.5 µm thick, with sphaerocytes of 10-25 µm diam., pale yellowish, wall 0.5 µm thick, laticiferous hyphae 4-6 µm diam., infrequent. Clamp connections absent.

Habitat.

Gregarious, under Quercus oleoides , infrequent.

Additional studied material.

MEXICO, Veracruz, Alto Lucero Co., 12 km SW Palma Sola (road Veracruz-Nautla) 25 June 2015, Corona 1127, Montoya 5191; October 11, 2016, Caro 103 (all at XAL).

Figures

Figure 2. Lactifluus species basidiomes and pileipellis a, b L. lorenae; c, d L. mexicanus. Scale bars: 40 mm (a), 20 mm (c), 2 μm (b, d).

Figure 3. Lactifluus lorenae microscopical characteristics a basidiospores b basidia c pleurocystidia d cheilocystidia. Scale bars: 5 µm (a), 10 µm (b-d).

Figure 5. SEM microphotographs of Lactifluus species a, b Lactifluus lorenae c, d L. mexicanus. Scale bar: 2 μm.