Bioacoustics of Russula pseudocatillus

ADDITIONAL SPECIMENS EXAMINED. — China . Guangdong Province , Zhaoqing City, Dinghu Mountain, 7.VI.2015 , J. B. Zhang K15060706 . DESCRIPTION Basidiomata Small, agaricoid. Pileus 2.5-4 cm in diam., plano-concave or applanate with a depressed center, some slightly decurrent, surface glabrous, slightly viscid when wet, very pale yellow (corn silk, #FFF8DC) at margin, with a pale greyish brown (tan, #D2B48C) center; margin slightly undulate, striate, rarely cracked. Lamellae Adnate, subequal, interveined, often forked near stipe, about 2 mm in height, very pale grayish yellow (beige, #F5F5DC), unchanging when bruised; edge entire, concolorous; lamellulae rather frequent, but not polydymous. Stipe 2.5-4 × 0.6-1 cm , central, cylindrical, sometimes slightly tapering upwards, surface dry, slightly longitudinally rugulose, a pale greenish-grayish yellow (goldenrod, #EEE8AA) in the upper part, burlywood at the bottom, stuffed at first, becoming hollow when old. Context Off-white (ivory, #FFFFF0), unchanging when bruised. Odour Indistinct. Taste Mild. Spore print Very pale. Basidiospores Broadly ellipsoid to subglobose, [40/2/2] 7.0-7.9-8.6 (-9.2) × (5.1- (5.5-6.1-6.6 (-6.7) µm, Q = (1.19-) 1.22-1.32-1.42, hyaline in 5% KOH; ornamentations amyloid, composed of conical to cylindrical warts up to 1.2 µm, isolated, never forming a reticulum; suprahilar spot unamyloid. Basidia 33-41.5 × 10.5-13 µm, 4-spored, rarely 2-spored, some containing oil droplets; sterigmata up to 8 µm long. Lamellar trama Composed of nested sphaerocytes surrounded by connective hyphae. Pleurocystidia 32-37.5 × 9.5-11.5 µm, clavate to subcylindrical, rarely fusiform, with obtuse to truncate apices, thin-walled, with abundant refractive granular contents, negative in SV. Cheilocystidia 33-47.5 × 9-12.5 µm, clavate, with mucronate to rostrate apex, thin-walled, some with refractive granular contents, unchanging in SV. Marginal cells not differentiated. Pileipellis Orthochromatic in cresyl blue, divided into two layers: suprapellis trichoderm, composed of ascending to erect hyphae; subpellis a cutis, composed of septate, thin-walled, hyaline hyphae; terminal cells clavate to cylindrical, with obtuse apices; subterminal cells cylindrical or slightly inflated. Pileocystidia Abundant, unchanging in SV, mostly 13-33 × 3-6 µm, onecelled, cylindrical, apex obtuse, with granular contents, also present in subpellis. Stipitipellis A cutis, orthochromatic in cresyl blue, composed of repent, thin-walled, septate hyphae up to 4.6 µm broad. Caulocystidia Frequent, clavate to cylindrical, 16-35 × 3-8 µm, with obtuse or rostrate apex, one-celled, with refractive contents, unchanging in SV. Stipe trama Composed of connective hyphae and nested sphaerocytes. Clamp connections Absent. Notes Russula catillus was reported from Korea , and the name refers to the resemblance of the pileus to a small bowl traditionally used for holding soy sauce. R. pseudocatillus F. Yuan & Y. Song , sp. nov. , is sharing similar overall color and shape with R. catillus . Dermatocystidia (both pileocystidia and caulocystidia) are present in our species, but were reported (in Lee et al. 2017 ) as absent in R. catillus , something that is highly unexpected and should be verified again as all of the presently known species in sect. Ingratae from any part of the world all have abundant dermatocystidia and abundant gloeoplerous elements in all of the tissues. Russula pseudocatillus F. Yuan & Y. Song , sp. nov. is very similar to this R. catillus , but it differs from the latter in its smaller basidiomata, irregular presence of lamellulae, much bigger basidiospores ornamented with higher warts that are never interconnected into a reticulum, and also because of its smaller pleurocystidia and poorly gelatinized pileipellis (see Tables 1 , 2 ).