Mucidula mucida var. venosolamellata
Mucidula mucida var. venosolamellata (Imazeki & Toki) R.H. Petersen
Index Fungorum number: IF 456952; Facesoffungi number: FoF 10364
Pileus 30–50 mm diam., firstly convex to broadly convex, expanding to plano-convex, becoming hemispheric when mature, with straight to slightly inflexed margin; soft and viscid when wet, smooth or glabrous when dry, white to dirty white (1A1), yellowish-white to greyish-yellow (4A2–4B3) at the center; margin white, striate. Lamellae adnate, white, broad to broadly ventricose, 5–8 mm thick, with concolorous eroded edge. Stipe 20–60 × 0.5–1 mm, cylindrical with wide bulbous 10–15 mm, covered with white fibrillose, with white fibrillose squamules to squamules at base zone or bulbous, on white to yellowish-white (3A2, 4A2) background. Annulus present at above of stipe, white, membranous. Context white in pileus, 2–4 mm thick; solid and white in stipe. Spores print white. Pileus 30–50 mm diam., firstly convex to broadly convex, expanding to plano-convex, becoming hemispheric when mature, with straight to slightly inflexed margin; soft and viscid when wet, smooth or glabrous when dried, white to dirty white (1A1), yellowish white to greyish yellow (4A2–4B3) at the center; margin white, striate-liked. Lamellae adnate, white, broad to broadly ventricose, 5–8 mm thick, with concolorous eroded edge. Stipe 20–60 × 0.5–1 mm, cylindrical with wide bulbous 10–15 mm, covered with white fibrillose, with white fibrillose squamules to squamules at base zone or bulbous, on white to yellowish white (3A2, 4A2) background. Annulus present at above of stipe, white, membranous. Context white in pileus, 2–4 mm thick; solid and white in stipe. Odor not observed. Taste mild. Spores print white.
Basidiospores 18.0–24.1 × 14.0–19.8 µm, Q= 1.09–1.45, subglobose to broadly ellipsoid, smooth, hyaline, thick-walled. Basidia 50.3–69.9 × 16.0–21.3 µm, clavate to broadly clavate, thick-walled, 4-spores, sometimes 2-spored. Cheilocystidia 15.0–22.1 × 5.0–7.2 µm, variable in shape, clavate, narrowly clavate, fusiform, occasionally capitate, thin walled. Pleurocystidia 39.2–58.1 × 14.5–20.4 µm, cylindrical to subcylindrical, thin-walled. Pileipelliis an ixotricchoderm to subhymeniderm made up of clavate to broadly terminal cells, 15.0–22.2 × 5–7.2 µm. Clamp-connections present.
Material examined: LAOS, Xiang Khouang Province, Phoukout District, Gnophe, Na Phouang, hamlet, 27 May 2018, Phongeun Sysouphanthong (HNL503504); Vientiane Capital, Xaythany District, Houay Yang Forest Reserve, 30 March 2018, Phongeun Sysouphanthong (HNL503530); ibedem 16 January 2016, Phongeun Sysouphanthong (HNL503214).
Notes: In the phylogenetic tree of Mucidula varieties is closely related. However, the morphology of M. mucidu var. asiatica have lamellae venose-reticulate anastomoses and pelielplis have narrowly clavate cells, while M. mucidu var. venosolamellata lacking anastomoses on the lamellae, with ixotricchoderm pileipellis with slender hyphae and different from M. mucida var. mucida by pileipellis composed of coralloid terminal cells and smaller basidiospores size (13–22 × 12–19.7 µm) (Petersen & Hughes 2010, Ushijima et al. 2012, Vizzini et al. 2012). The specimens of M. mucida from Laos are characteristic of plano-convex pileus, gelatinous surface, and lamellae adnate. Furthermore, distinguished ixotricchoderm to subhymeniderm on the pileipellis. Therefore, those morphologies are fit well with M. mucidu var. venosolamellata from China and Japan with similar macro-shapes, and micro characteristic. The terminal cells of pileipellis (15.0–22.2 × 5–7.2 µm), cheilocystidia (15–22.1 × 5–7.2 µm) and pleurocystidia (39.2–58.1 × 14.7–20.4 µm) of Laos specimens are smaller than Japanese specimen (terminal cells of pileipellis 21–68.5 × 4–11 µm, cheilocystidia 106–115 × 17–62, pleurocystidia 103–227 × 20–60 µm) and Chinese specimen (terminal cells of pileipellis 22–40 × 10–15 µm, cheilocystidia 78–140 × 9–20 µm, pleurocystidia 157–200 × 20–40 µm) (Ushijima et al. 2012, Vizzini et al. 2012). However, the variation in morphology can be brought about by the different geographical hiatus and environmental conditions that can change the phenotype of mushrooms (Hewitt et al. 2016). The phylogenetic analysis base pair differences on ITS sequences furthermore supports the identification of Laos specimens as M. mucidu var. venosolamellata.
Fig1. Phylogenetic tree generated by ML analysis of ITS sequence data of Mucidula species. The analyses included 57 species and the tree was rooted with Dactylosporina steffenii (HM005073). Tree topology of the ML analysis was similar to the MP and BYPP. The best scoring RAxML tree with a final likelihood value of -3823.834840 is presented. The matrix had 348 distinct alignment patterns, with 6.85% of undetermined characters or gaps. Estimated base frequencies were as follows: A = 0.209642, C = 0.228142, G = 0.235041, T = 0.327175; substitution rates AC = 0.890824, AG = 1.893300, AT = 0.595315, CG = 1.040815, CT = 2.222406, GT = 1.000000; gamma distribution shape parameter α = 0.597222. Maximum parsimony analysis of 402 constant characters and 239 informative characters resulted in 100 equally most parsimonious tree of 10 steps (CI = 0.792, RI = 0.896, RC = 0.710, HI = 0.208). RAxML bootstrap support values ≥50% and maximum parsimony bootstrap support values ≥50% are shown near the nodes. The scale bar indicates 0.1 change per site. New isolates recovered are in red.