Lactifluus indicus K. N. A. Raj & Manim., 2016

Deepna Latha, K. P., Anil Raj, K. N., Farook, V. Adnaan, Sharafudheen, Shahina A., Parambil, Neeraja K. & Manimohan, Patinjareveettil, 2016, Three new species of Russulaceae from India based on morphology and molecular phylogeny, Phytotaxa 246 (1), pp. 61-77 : 69-71

Lactifluus indicus K. N. A. Raj & Manim. , sp. nov. Figs. 1C–D ; Figs. 3A–G ; Fig. 5B

MycoBank MB 815042

Etymology:—The specific epithet refers to the country where this species was first discovered.

Diagnosis:— Lactifluus indicus has a dark brown pileus, adnate to rather sinuate, anastomosing, orange white lamellae, an indistinct odor, pleurocystidia and a lampropalisade type pileipellis.

Holotype:— INDIA. Kerala State: Kozhikode District, Malabar Botanical Garden, Olavanna , 29 July 2011, K. N. Anil Raj, AR781 ( CAL 1282 ).

Description:— Basidiomata small, pleurotoid. Pileus 6–19 mm diam., conchate to flabelliform; surface grayish brown (6F3, 6F4/OAC623) or dark brown (6F6, 6F7/OAC635) all over when very young, becoming brown (6E7) towards the margin with age, hispidulous when very young, becoming tomentose or velutinous with age, not striate, somewhat sulcate at maturity; margin inrolled when very young, becoming decurved to somewhat reflexed at maturity, initially white, becoming brown (6E7/OAC635) with age, initially entire, becoming crenate or somewhat wavy with age. Lamellae adnate or rather sinuate, anastomosing, subclose, initially white, becoming orange white (6A2), up to 3 mm wide, with lamellulae of 2-4 lengths; edge initially concolorous with the sides, gradually developing a brown (6E7/OAC658) tint up to 1/4 th of lamella from the point of attachment with the pileus, entire to the naked eye, finely torn under a lens. Stipe either absent or inconspicuous, 1–2 × 1–2 mm. Subiculum well-developed, whitish. Odor and taste not distinctive.

Basidiospores (5)6–7(8) × (4.5)5–6.5 (6.46 ± 0.67 × 5.59 ± 0.48) μm, Q = 1–1.6, Qm = 1.17, subglobose with a prominent hilar appendix, with a strongly amyloid ornamentation composed of interconnected warts forming a complete reticulum up to 2.7 μm high. Basidia 24–51 × 7–13 μm, cylindrico-clavate or clavate, hyaline, thin-walled, 4-spored; sterigmata up to 5 μm long. Lamella edge heterogeneous composed of cheilocystidia and marginal cells often intermixed with few basidia. Marginal cells 18–59 × 3–6 μm, clavate or flexuouso-cylindric, septate, thinto slightly thick-walled, hyaline. Cheilocystidia 35–68 × 4–9 μm, cylindrical or ventricose with an acuminate or mucronate apex, thin-walled, hyaline, with granular refractive contents. Pleurocystidia 46–98 × 6–12 μm, scattered, similar in morphology to cheilocystidia, thin-walled, hyaline, with granular contents. Lamellar trama somewhat irregular, composed of both narrow and slightly inflated hyphae and a few lactifers; hyphae 2–15 μm wide, thin- to slightly thick-walled, hyaline, inamyloid. Pileus trama interwoven, with a few lactifers; hyphae 3–11 μm wide, thin-walled, hyaline, inamyloid. Pileipellis a lampropalisade, 60–90 μm thick; elements of suprapellis 9–48 × 4–7 μm, versiform: narrowly conical, setiform, cylindrical, clavate or rarely narrowly lageniform, often septate, with brown or yellowish brown intracellular contents, slightly thick-walled (up to 1 μm thick); elements of subpellis 7–31 × 8–27 μm, subglobose or globose, hyaline or with brown intracellular contents, thick-walled (up to 1.5 μm thick). Subiculum composed of strands of thick-walled hyphae 3–5 μm wide, with walls 1–2 μm thick. Clamp connections absent.

Habitat:—in small groups, on dead tree stumps or bark of living trees.

Geographical distribution range:—known only from two localities in Kozhikode District of Kerala State, India.

Additional specimens examined:— INDIA. Kerala State: Kozhikode District, Atholi, Vallikkattu Kavu sacred grove, 6 August 2011, K. N. Anil Raj, AR792 (CAL 1283).

Comments:—Characters such as the pleurotoid basidiomata with a brown pileus, the basidiospores with a reticulate ornamentation, the palisade-type pileipellis with globose cells in the subpellis and the occasional presence of pleuro- and cheilocystidia fit well for Lactifluus subg. Gerardii ( Stubbe et al. 2010; Stubbe et al. 2012a). Lactifluus conchatulus Stubbe & Verbeken ) Stubbe (in Stubbe et al. 2012b: 484), a species discovered from Thailand ( Stubbe et al. 2012a), is similar to Lf. indicus in having basidiomata of similar shape and size, basidiospores of similar size (6.2– 7.8 (8.0) × 5.1–5.9–6.6 μm) and almost similar shape with somewhat similar surface ornamentations, cheilocystidia of rather similar size and shape and somewhat similar pileipellis structure. However, Lf. conchatulus has a white-colored pileus, white, subdecurrent lamellae which turn brownish yellow on bruising, a distinct, fragrant odor and lamellae devoid of pleurocystidia. The present species is also somewhat similar to Lactarius brunellus S.L. Mill., Aime and T.W. Henkel (in Miller et al. 2002: 546), a species from Guyana ( Miller et al. 2002). Lactifluus indicus and Lactarius brunellus have basidiomata of similar size and shape, somewhat similar color and surface features of the pileus and a rather similar habitat. However, L. brunellus has subglobose to short ellipsoid basidiospores with an echinulatespinose ornamentation with rare connectives, a prominent hilar appendix and a large suprahilar plage, pseudocystidia, lamellae devoid of pleurocystidia and an epithelium-type pileipellis. Lactarius multiceps S.L. Mill., Aime and T.W. Henkel (in Miller et al. 2002: 549) another species from Guyana, somewhat resembles the present species in having a pileus with similar surface features. However, L. multiceps differs in all other macro- and microscopic features ( Miller et al. 2002). Lactarius panuoides Singer (1952: 300) differs from the present species in having an off-white pileus, decurrent lamellae, larger basidiospores (7.5-9.5 × 7-8 μm) with a different surface ornamentation, pseudocystidia, lamellae devoid of pleurocystidia, encrusted laticiferous hyphae, sphaerocytes and a different type of pileipellis.

Lactifluus genevieveae (Stubbe & Verbeken) Stubbe, X.H. Wang & Verbeken (in Stubbe et al. 2012a: 484), a species from Tasmania ( Stubbe et al. 2012a), has basidiomata of somewhat similar size and shape, similar basidiospore ornamentation and similar cheilo- and pleurocystidia with granular contents. Lactifluus genevieveae , however, differs from the present species in having white basidiomata, larger basidiospores (7.1–8.3–9.6 × 6.5–7.3–8.2 μm), both 4- and 3-spored basidia and a palisade-type pileipellis. Lactifluus chrysocarpus E.S. Popov & O.V. Morozova (2013: 95) and Lf. igniculus O.V. Morozova & E.S. Popov (2013: 95) , two recently described pleurotoid species from Vietnam ( Morozova et al. 2013), differ from Lf. indicus in having bright yellow and deep orange basidiomata respectively.

No close hits with zero e-values were resulted in a BLASTn search using the ITS sequences (CAL 1282: 415 bp, CAL 1283: 411 bp) of Lf. indicus . While using nLSU sequence (CAL 1282: 874 bp, CAL 1283: 843 bp), the closest hit was Lactifluus uyedae (GenBank AF218562; Identities = 857/875 (98 %); 825/845 (98 %), Gaps = 1/875 (0 %); 2/845 (0 %)). Lactifluus uyedae ( Singer 1984: 436) Verbeken (in Stubbe et al. 2012b: 485) is somewhat similar to the present species in having a pileus of similar shape and surface features, an inconspicuous stipe and lamellae showing the pleuro- and cheilocystidia and marginal cells. However, Lactifluus uyedae is a pure white species that also differs from the present species in all other macro- and microscopic characters ( Henkel et al. 2000).

Figures

FIGURE 1. A–F: Basidiomata of the three new species. A–B. Lactifluus umbonatus. C–D. Lf. indicus. E–F. Lactarius keralensis. Scale bars: A, C–F = 10 mm; B = 5 mm. Photos: A–B. By K.P.D. Latha; C–D. By K.N.A. Raj; E–F. By V.A. Farook.

FIGURE 3. A–G: Lactifluus indicus (CAL 1282, holotype). A. Basidiomata; B. Basidiospores; C. Basidia; D. Pleurocystidia; E. Cheilocystidia; F. Marginal cells; G. Pileipellis. Scale bars: A = 5 mm; B = 5 μm; C–G = 10 μm.

FIGURE 5. A–C: SEM images of basidiospores of the three new species: A. Lactifluus umbonatus (CAL 1241, holotype). B. Lactifluus indicus (CAL 1282, holotype). C. Lactarius keralensis (CAL 1281, holotype). Scale bars: A–B = 5 μm; C = 2 μm.