Russula cf. densifolia

Russula cf. densifolia

Pileus 43 – 78 mm diam., convex when young, then plane, shallowly depressed or infundibuliform when mature, surface dry, more or less smooth, sometimes velvety at centre, white (155D), becoming to moderate olive brown (N199A), margin incurved when young and becoming decurved when mature. Lamellae 30 – 40 mm wide, adnexed to adnated, sub distant to close, white (NN155D), bruising and discolouring slowly reddish, then greyish to blackish, edge entire. Stipe 40 – 50 × 20 – 25 mm, central, cylindrical, sometimes tapering, surface smooth, whitish (NN155D) at first, but soon darkening like the pileus, bruising reddish, then blackish. Context rather firm, hard, solid to stuffed or hollow when mature in stipe, white, unchanging after treating with KOH, FeSO4 and NH4OH. Taste mild. Odour slightly fragrant. Spore print white. Basidiospores 7 – 9 × 6 – 9 μm (Q= 1–1.14 – 1.16), sub globose to broadly ellipsoid, ornamentation completely reticulate, amyloid. Basidia 35 – 40 × 5.0 – 8.0 μm, subclavate to clavate, with 4 spores; sterigmata 1.50 – 3.75 μm long. Pleurocystidia 70 – 100 × 9.0 – 12.5 μm, not abundant, subcylindrical to cylindrical, or capitulate, thin-walled. Cheilocystidia 47 – 70 × 9.0 – 12.50 μm, similar to pleurocystidia. Lamellar trama composed of large sphaerocytes surrounded by connective hyphae, sphaerocytes globose to elliptical. Pileocystidia not observed.

Note: Russula cf. densifolia was similar to R. densifolia in having indistinguishable macroscopic features. But Russula cf. densifolia differs from R. densifolia by having smaller basidiospores and lower warts (< 5 μm) on the basidiospore surface.

Fig. 1 Phylogenetic tree of eight Russula specimens, one Lactarius specimen (indicated in bold), and some reliable best-hit sequences from GenBank database using Maximum Likelihood method. Number at the node indicates bootstrap values. Termitomyces microcarpus was used as an outgroup.