Lactarius taedae Silva-Filho, Sulzbacher & Wartchow, 2018

Silva-Filho, Alexandre G. S., Sulzbacher, Marcelo A., Ferreira, Renato J., Baseia, Iuri G. & Wartchow, Felipe, 2018, Lactarius taedae (Russulales): an unexpected new gasteroid fungus from Brazil, Phytotaxa 379 (3), pp. 234-246 : 236-238

Lactarius taedae Silva-Filho, Sulzbacher & Wartchow sp. nov. ( Figs. 2–4 )

Mycobank:—MB 827484

Type:— BRAZIL, Rio Grande do Sul, Santa Maria, Campus da Universidade Federal de Santa Maria , 29°43’19.65” S 53°42’48.45” W, 113 m a.s.l., under Pinus taeda , 17 May 2017, M. A. Sulzbacher 510 ( SMDB 18030 holotype!; UFRN-Fungos 2950) .

Diagnosis:—Basidiomata gasteroid, hypogeous or partly epigeous, globose to ovoid. Peridium persistent, reddish yellow to dark brown. Gleba labyrinthoid, pale brown. Latex white, unchanging. Basidiospores 9–12.5 × (8.5–)9–11.5(– 12) μm, globose to broadly ellipsoid, ornamentation a complete and dense reticulum, up to 2 μm high. Pseudocystidia and cystidia absent. Peridiopellis a cutis of repent, firmly woven hyphae.

Description:—Basidiomata gasteroid, 18–31 mm broad, 15–22 mm high, globose to ovoid, sometimes lobed. Peridium persistent, reddish yellow (7.5YR8/6) to dark brown (7.5YR5/8), up to 0.5 mm thick, smooth and dry. Stipe absent. Rhizomorphs absent. Gleba labyrinthoid, irregular, with 2–4 columns per mm, empty, whitish to pale to very pale brown (10YR8/3), unchanging when cut. Hymenophoral tramal tissue firm, gray (10YR6/1). Latex white, unchanging, exuding only from the tramal tissue. Columella rudimentary to well developed, composed of radiating dendritic veins arising from a central main vein 0.5–2 mm diam., grayish brown (10YR5/2). Odor sweet then fruity in mature basidiomata. Taste mild.

Basidiospores 9–12.5 × (8.5–)9–11.5(–12) μm, (excluding ornamentation), L = 11 μm, W = 9.9 μm, Q = 1.09– 1.33, Qm=1.11; globose, subglobose to broadly ellipsoid, thick walled with walls 0.8‒1.4 μm thick; ornamentation forming a complete and dense reticulum, 1‒2 μm high, ridges bearing obtuse warts, hyaline, amyloid; hilar appendix thin walled, 1‒2 μm long, inamyloid. Basidia 33–70.5 × 7.5–15 μm, clavate to cylindric-clavate rarely fusoid, predominantly 2-spored, occasionally 1- or 4-spored, thin-walled, hyaline, some with refractive content, arising from subhymenium. Cystidia and pseudocystidia absent. Peridiopellis a cutis of repent, firmly woven hyphae 2‒5 μm in diam., pale/colorless, some with yellowish refractive content; in some points forming semi-erect to ascendant short to clavate terminal elements 19‒36 × 3.5‒5 μm, thin walled, hyaline sometimes with yellowish refractive content, inamyloid. Lactifers abundant in the gleba. Sphaerocytes and clamp-connections absent from all tissues examined.

Chemical reaction:—Gleba brownish red in sulpho-vanillin. Peridium and gleba unchanging in KOH.

Etymology:—In reference to the plant symbiont species, Pinus taeda .

Habitat:—In small groups of 2–5 basidiomata partially epigeous to hypogeous (at 10 mm deep in soil), under needle duff of Pinus taeda in plantation of Pinus taeda .

Distribution:—Known only from type locality.

Materials examined:— BRAZIL, Rio Grande do Sul, Santa Maria, Campus da Universidade Federal de Santa Maria , 29°43’19.65” S 53°42’48.45” W, 113 m a.s.l., associated with Pinus taeda , 17 May 2017, M. A. Sulzbacher 510 ( SMDB 18030 ; UFRN-Fungos 2950) and M. A. Sulzbacher 511 ( SMDB 18031 ; UFRN-Fungos 2951) .

Figures

FIGURE 2. Lactarius taedae basidiomata in situ M.A. Sulzbacher 510 (holotype). (bars = 10 mm). Photos by: Marcelo A. Sulzbalcher.

FIGURE 3. Lactarius taedae. a–c M.A.Sulzbacher 510 (holotype). a) Basidiospores b) Basidia, c) Peridiopellis. (bars = 10 μm). Drawings by:Alexandre G. S. Silva-Filho.

FIGURE 4. Lactarius taedae SEM micrographs of the basidiospores a,b M.A. Sulzbalcher 510 (holotype). a) Front view b) Side and front view. (bars = 5 μm).