Laccaria violaceotincta K. P. D. Latha, K. N. A. Raj & Manim., 2019

Deepna Latha, K. P., Anil Raj, K. N. & Manimohan, Patinjareveettil, 2019, Laccaria violaceotincta: a new species from tropical India based on morphology and molecular phylogeny, Phytotaxa 392 (2), pp. 140-146 : 141-144

Laccaria violaceotincta K. P. D. Latha, K. N. A. Raj & Manim. , sp. nov. Fig. 1

MycoBank MB 828942

Etymology:— violaceotincta (Latin) , violet-tinted, refers to the color of the basidiocarps of this species.

Diagnosis:—Differing from Laccaria vinaceoavellanea in having smaller basidiocarps with a glabrous pileus that lacks a furfuraceous surface, violet-tinted lamellae that are rather narrow and occasionally furcate, a stipe that is covered with reddish gray or violet gray fibrils, the presence of both 2- and 4-spored basidia, occasional presence of crassobasidia, versiform cheilocystidia, a cutis-type pileipellis, a cutis-type stipitipellis disrupted by trichodermial elements, and a distinctive nrITS sequence.

Holotype:— INDIA. Kerala State: Kollam District, Kulathupuzha, Sasthanada , myristica swamp, 20 September 2014, K. P. Deepna Latha DKP303 ( CAL 1389 ). GenBank accession: MK141034 (nrITS).

Description:— Basidiocarps small, somewhat collybioid. Pileus 4–38 mm diam., initially convex with a slight central depression, becoming applanate or somewhat plano-concave still with a central depression at maturity; surface dark brown (9F5/OAC621) at the center, reddish brown (9D5/OAC624) towards the margin when young, becoming violet brown (11E4/OAC603) at the center and on the striations, dull red (11C3/OAC583) elsewhere, strongly hygrophanous and becoming grayish violet (17B3/OAC410), initially pellucid-striate, becoming somewhat sulcatestriate, glabrous; margin incurved when young, becoming decurved to somewhat reflexed with age, finely crenate or wavy. Lamellae adnate or emarginate with a small decurrent tooth, subdistant, rarely furcate, violet gray (16C2/ OAC402), up to 3 mm wide, with lamellulae of 3 lengths; edge crenate, concolorous with the sides. Stipe 16–50 × 1.5– 4 mm, central, terete, equal or slightly tapering towards the apex, solid; surface reddish brown (8D4, 8D5/OAC604), covered with appressed reddish gray (12C2/OAC584) or violet gray (17B2/OAC403) fibrils over entire length; base enlarged, with white, basal mycelium. Odor and taste not distinctive. Spore print not obtained.

Basidiospores (6)7–8(9.5) × (6)7–8(9.5) (7.54 ± 0.81 × 7.29 ± 0.85) μm, Q= 1–1.17, Qm = 1.04, globose to subglobose with fine spines up to 2 μm long, with a conspicuous hilar appendix up to 1.5 μm long, inamyloid. Basidia 31–47 × 10–13 μm, clavate, hyaline or pale yellow with amorphous contents, thin-walled, 2- to 4-spored; sterigmata up to 10 μm long. Crassobasidia occasional. Lamella-edge sterile or heterogeneous. Cheilocystidia 19–104 × 4.5–10 μm, versiform; flexuose, flexuoso-cylindrical, clavate, clavate with a mucronate apex, pedicellate with a capitate apex or irregular, occasionally thick-walled towards the base (up to 1.5 μm thick), with hyaline, amorphous contents. Pleurocystidia absent. Lamellar trama subregular; hyphae 2.5–15 μm wide, thin- to slightly thick-walled, hyaline or with a pale brown wall pigment; a few oleiferous hyphae present. Pileus trama interwoven; hyphae 2–13 μm wide, slightly thick-walled (up to 1 μm thick), with a pale yellow wall pigment. Pileipellis a cutis; hyphae 2–22 μm wide, thin-walled, with a pale brown wall pigment and a hyaline encrustation. Stipitipellis a cutis disrupted by trichodermial patches towards the apex; trichodermial elements 20–121 × 4–12 μm, with a pale yellow wall pigment and hyaline amorphous contents; hyphae 2–17 μm wide, thin-walled, with a pale yellowish brown wall pigment. Caulocystidia absent. Clamp connections observed on all hyphae.

Habitat: — On soil, among decaying litter, scattered or in small groups.

Geographical distribution range:—Known only from the type locality in Kerala State, India.

Additional specimens examined:— INDIA. Kerala State: Kollam District, Kulathupuzha, Sasthanada , myristica swamp, 29 September 2010, K. N. Anil Raj AR359 ( CAL 1392 ) ; 21 September 2014, K. P. Deepna Latha DKP311 ( CAL 1390 ), 4 November 2015, K. P. Deepna Latha & K. N. Anil Raj DKP 419 ( CAL 1391 ) .

Comments:—A BLASTn search with the nrITS (686 bp) sequence of L. violaceotincta showed L. vinaceoavellanea as the closest hit (97% identity; JN942803) followed by L. yunnanensis (96% identity; JQ670897). Laccaria vinaceoavellanea Hongo (1971: 62) , a species originally reported from Japan ( Hongo 1971) and later redescribed by Mueller (1992) based on the type specimen, shares a few features with L. violcaeotincta such as a depressed pileus, adnate to subdecurrent lamellae, globose and subglobose basidiospores of almost the same size ((6.4)7.4–9.2(-9.7) × (6.4)7.4–9.2(9.7)) μm, and the presence of clamp connections ( Mueller 1992). Laccaria vinaceoavellanea , however, differs from L. violcaeotincta in having larger, brownish vinaceous basidiocarps with a pileus which is furfaraceous at the disc, a stipe which is always equal, basidiospores with longer spines (3.2 μm long), consistently 4-spored basidia, and a pileipellis which is disrupted with scattered fascicles of perpendicular hyphae. Also, Mueller (1992) observed no cheilocystidia in L. vinaceoavellanea .

Laccaria yunnanensis Popa, Rexer, Donges, Zhu L. Yang & G. Kost (in Popa et al. 2014: 1113), a species recently described from China ( Popa et al. 2014), resembles L. violcaeotincta in having glabrous and translucent-striate pileus, basidiospores of almost similar size ((7.5) 8–9 × (7.5) 8–10 μm) and shape (globose to subglobose), a lamella-edge with cheilocystidia, and clamped hyphae. It, however, differs from L. violcaeotincta in having gregarious, larger basidiocarps (pileus 60–100 mm, lamellae 5 mm wide, stipe 30–100 × 3–15 mm) with a brownish to flesh-colored pileus, adnexed to adnate, flesh-colored lamellae, a glabrous stipe, a hymenium showing pleurocystidia and consistently 4-spored basidia. Laccaria olivaceogrisea Vellinga (1986: 224) , an Indian species described by Vellinga (1986), resembles L. violaceotincta in having basidiocarps with a faint violaceous hue, basidiocarps of somewhat similar size (pileus 9–32 mm diam. and stipe 23–45 × 2.5–6 mm), an apically tapered stipe with a white basal mycelium, globose basidiospores of almost similar size (7.5–9 × 7.5–9.5 μm), and clamped hyphae. Laccaria olivaceogrisea however, is distinguished from L. violcaeotincta by its olivaceous gray basidiocarps with a pileus that is minutely tomentose to slightly floccosetomentose at the disc, strongly intervenose lamellae, a fistulose stipe with a strongly fibrillose to subcostate surface, basidiospores with slightly longer spines (2.5 μm long), consistently 4-spored basidia, a fertile lamella-edge devoid of cheilocystidia, a cutis-type pileipellis with ascending hyphae, and a cutis-type stipitipellis ( Vellinga 1986).

The phylogram ( Fig. 2 ) generated from the ML phylogenetic analysis using nrITS sequence data recovered a monophyletic Laccaria with maximum bootstrap support (100% BS). Within this clade, the newly discovered L. violaceotincta was found clustered with two tropical species, L. yunnanensis and L. vinaceoavellanea , with high bootstrap support (100% BS). Within this cluster, however, L. violaceotincta formed a lineage distinct from other two species with strong bootstrap support (85% BS).

Based on the morphological features such as the highly hygrophanous and violet-tinted pileus, violaceous lamellae and stipe, globose basidiospores with fine spines and the presence of both 2- and 4-spored basidia, this new species can be placed either in sect. Laccaria or in sect. Amethystinae of Laccaria ( Vellinga 1995) .

Figures

FIGURE 1.A–F: Laccaria violaceotincta (CAL 1389, holotype).A.Basidiocarps in their natural habitat; B. Scanning electron micrograph (SEM) of basidiospore; C. Basidium; D. Cheilocystidia; E. Pileipellis. F.Vertical section of stipitipellis towards the apex of the stipe.Scale bars: A = 10 mm; B–D = 10 μm; E–F = 20 μm.

FIGURE 2. RAxML tree based on ML analysis of nrITS sequence data depicting the taxonomic position of L. violaceotincta within the genus Laccaria. The newly proposed species is indicated in bold face. GenBank accession numbers and geographical origin are given after the name of each taxon. Bootstrap values for ML are placed above or below the branches. BS values ≥50% are shown.