Corneriella indica Raj & Manim., 2015

Anil Raj, K. N., Deepna Latha, K. P., Sánchez-García, Marisol & Manimohan, Patinjareveettil, 2015, A new species of the genus Corneriella from India supported by morphological and molecular data, Phytotaxa 213 (2), pp. 102-112 : 107-109

Corneriella indica Raj & Manim. , sp. nov. Figs. 1 , 2 A–F

MycoBank MB 809233

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

Diagnosis:—Tricholomatoid basidiomata with a brown pileus with appressed-fibrillose surface, thick lamellae with dark brown edges, a sterile lamella edge composed of projecting tramal hyphae with cystidioid terminal elements, subglobose and amyloid basidiospores, and a cutis-type pileipellis disrupted by trichodermal patches are the diagnostic features of this species. Differing from Corneriella bambusarum (Desjardin & Hemmes) Sánchez-García in having an appressed-fibrillose pileus, adnate to subdecurrent lamellae with a dark brown lamella edge, a sterile lamella edge composed of projecting tramal hyphae with cystidioid terminal elements, and slightly gelatinized pileipellis and stipitipellis hyphae.

Basidiomata small to medium-sized, tricholomatoid.Pileus 16–56mm diam., hemispherical or convex when young, becoming somewhat campanulate and finally plano-convex with a broad umbo; surface dark brown (7 F4 )/( OAC635 ) at the center and on the fibrils and grayish brown (7 E3 )/( OAC626 ) elsewhere when young, becoming brownish orange (6 C3 )/( OAC669 ) or brown (6 F4 )/( OAC636 , OAC639 ) at the center and light brown (6D4)/( OAC660 , OAC661 ) towards the margin with age ; not hygrophanous, not pellucid-striate, initially slightly recurved-squammulose towards the margin and densely appressed-fibrillose elsewhere, becoming entirely appressed-fibrillose with age; margin slightly incurved and finely appendiculate when young, becoming somewhat straight and crenate with age. Lamellae adnate to subdecurrent, rather thick, occasionally furcate in both directions, crowded, initially orange gray (6 B2 )/( OAC676 ), becoming brownish gray (6D2, 7 C2 )/( OAC627 ) or grayish brown (6 E3 )/( OAC723 ), with lamellulae of 3–6 lengths, up to 4 mm wide ; edge entire when very young, becoming crisped with age, initially concolorous with the sides, becoming dark brown (6 F6 )/( OAC639 ) or brownish gray (7D 2, 7E 2)/( OAC626 , OAC627 ). Stipe 32–67 × 5–11 mm, central, terete or slightly compressed, equal or slightly tapering towards the base, fibrous, solid ; surface grayish brown (5D 3, 5E 3)/( OAC662 ) or brownish gray (7 E2 )/( OAC627 ), appressed-fibrillose all over, densely so when young, finely pruinose toward the apex ; base whitish, with scanty basal mycelium. Context soft, up to 6 mm wide, off-white or orange gray (6 B2 )/( OAC676 ). Odor and taste not distinctive .

Basidiospores 4–7 × 3–5 (5.10±0.81 × 4.33±0.83) μm, Q = 1–1.5, Qm = 1.19, subglobose, thin-walled, hyaline, amyloid. Basidia 18–31 × 5–7 μm, clavate, thin-walled, hyaline or very pale yellow, 4-spored; sterigmata up to 3.5 μm long. Lamella edge sterile, composed of projecting tramal hyphae with cystidioid terminal elements; terminal elements 46–85 × 9.5–17 μm, narrowly clavate, slightly thick-walled, with a grayish brown plasmatic pigment and faint spiral encrustations. Cheilocystidia absent. Pleurocystidia absent. Lamellar trama subregular, broad, inamyloid, composed of a central part made of inflated (5–20 μm), short-celled, hyaline elements flanked on either side by a zone of narrow (2.5–6 μm) hyphae with a brownish wall pigment. Pileus trama interwoven; hyphae composed of inflated elements 41–90 × 5–20 μm, gelatinized, thin-walled, with a pale yellow wall pigment, inamyloid. Pileipellis a cutis disrupted by trichodermal patches; hyphae slightly gelatinized, thin-walled; terminal elements cystidioid, 70–122 × 8–13 μm, narrowly clavate, thin-walled, with a pale yellow wall pigment and yellowish brown plasmatic contents, with faint spiral encrustations. Stipitipellis a disrupted cutis; hyphae 7–9 μm wide, slightly gelatinized, pale yellow or pale yellowish gray, thin-walled. Caulocystidia absent. Clamp connections seen on all hyphae.

Habitat:— scattered or in small groups, on soil, among decaying litter on forest floor, from a moist deciduous forest, on the bank of Peechi Dam reservoir where the major tree species include Terminalia spp. , Tectona grandis L.f. and Wrightia tinctoria R.Br. and the undergrowth consists mainly of Chromolaena odorata (L.) R.M. King & H. Rob., Helicteres isora L., and Glycosmis pentaphylla (Retz.) DC.

Geographical distribution range:—known only from Kerala ( India).

Type:— INDIA. Kerala State: Thrissur District, Peechi Forest, 1 November 2011, K. N. Anil Raj, AR920 (holotype K(M)190587!).

Additional specimens examined:— Corneriella indica : INDIA. Kerala State: Thrissur District, Peechi Forest , 16 June 2011, K. N.Anil Raj, AR633 ( K ( M)190588!) ; Corneriella bambusarum : USA. Hawaii, Oahu, Manoa Valley: Manoa Falls Trail , 8 January 1992, D. E. Desjardin 5462! ( NY: Isotope). Maui , Koolau State Forest Reserve , Na’ili’iliha’ele Trail , 28 August 1996, D. E. Desjardin 6572! ( NY: Paratype) .

Comments:—Phenetically, this agaric enters into the concept of Corneriella as circumscribed by Sánchez-García et al. (2014) owing to its tricholomatoid fruit bodies occurring on soil with smooth, thin-walled, amyloid basidiospores, a hymenium devoid of pleurocystidia, a cutis-type pileipellis disrupted by trichodermal patches and hyphae with clamp connections. However, conspicuous cheilocystidia, one of the defining features of the genus, are missing in the Indian species. Nonetheless, the lamella edges are still sterile and composed of projecting tramal hyphae with cystidioid terminal elements. This microscopic feature of C. indica is unique among the species of the genus.

Corneriella bambusarum , originally described from the Hawaiian Islands by Desjardin & Hemmes (2001) and the type species of the genus, has a pileus with somewhat similar size, shape and color, furcate lamellae, amyloid and almost similar-sized basidiospores (5.4–7 × 4.2–5.2 μm) and clamp connections. However, C. bambusarum has a granulose pileus, adnexed or sinuate lamellae of different color, ovate to broadly ellipsoid basidiospores, true and versiform cheilocystidia, non-gelatinized pileipellis hyphae devoid of encrustations and a different habitat. Corneriella humicola ( Corner 1994) differs in having a fetid odor in mature basidiomata, subtomentose to scurfy-pruinose pilei, distinctly decurrent, narrower (1–2.5 mm) lamellae, and versiform cheilo- and caulocystidia.

In addition, the molecular phylogenetic analysis recovers this taxon as part of Corneriella ( Fig. 3 ) as an independent lineage separated from other species of the genus and shows that C. indica is sister to C. humicola and C. bambusarum .

As Corneriella is a very recently described genus based on previously described species, there is the possibility that someone has recorded the present species under some other name from this region. However, as far as we know, there are no authentic previous records of either Porpoloma or Cantharellula from both India and adjacent Sri Lanka ( Manjula 1983; Pegler 1986; Natarajan et al. 2005; Farook et al. 2013). Also, extensive searches in the literature on agarics of the region (e.g., Sathe & Daniel 1980; Sathe & Deshpande 1980; Sathe & Kulkarny 1980; Pegler 1986; Mohanan 2011) did not reveal a previously published species description matching that of C. indica . Corner (1994) had described only one species of Cantharellula , C. humicola , from Malaysia.

Figures

FIGURE 1. Corneriella indica (K(M)190587, holotype). Basidioma. Scale bar: 10 mm. Photo: Taken by Mr K. N. Anil Raj.

FIGURE 2. Corneriella indica (K(M)190587, holotype), a. Basidiospores. b. Basidium. c. Lamella edge showing projecting tramal hyphae with cystidioid terminal elements. d. Cystidioid terminal element of lamellar trama. e. Pileipellis. f. Stipitipellis. Scale bars: 10 μm. Photos: Taken by Ms K. P. Deepna Latha.

FIGURE 3. Maximum likelihood (ML) phylogram (based on a concatenated dataset comprising ITS, nLSU, nSSU, rpb2) of the Tricholomataceae showing the placement of Corneriella indica. Bootstrap values ≥ 70% are indicated. Clitocybe nebularis, Entoloma sinuatum and Singerocybe adirondackensis are used for outgroup purposes.