Clavulinopsis aurantiaca Araujo-Neta, Silva & Gibertoni.
MycoBank: MB 816939 Facesoffungi number: FoF02463
Etymology: aurantiaca (Latin) = orange-coloured, referring to the colour of the basidiomata.
Holotype: URM 84216.
Basidiomata simple, 1.5–3 cm, solitary or in small groups, slender, with sharp tips, acute, robust, orange (48), with whitish base (78 W) when fresh. Basidiospores globose, rarely subglobose, 5–6 x 5–6 um, Q = 1.01, hyaline, guttulate or not, thinwalled, with short apiculus (0.2–0.5 um), IKI-. Hyphal system monomitic, tramal hyphae parallel, hyaline, abundantly clamped, 2–3 um wide, inflated up to 10 um, also clamped, subhymenium tightly interwoven. Cystidia of any kind absent. Basidia elongate-clavate, 35–37 x 5–9 um, hyaline, guttulate, with 4 (rarely 5) stout sterigmata, 5–6 um long, clamped at the base.
Material examined: BRAZIL, Pernambuco: Tamandare ´, Reserva Biologica de Saltinho, August 2011, L.S. AraujoNeta (URM 84216, holotypus; isotype in O); BRAZIL, Pernambuco, Tamandare ´, Reserva Biolo ´gica de Saltinho, February 2011, L.S. Araujo-Neta (URM 84212), July 2011, L.S. Araujo-Neta (URM 84212), March 2012, L.S. AraujoNeta (URM 84272), June 2013, L.S. Araujo-Neta & V.R. Coimbra 44NA (URM 85691), L.S. Araujo-Neta & V.R. Coimbra 45NA (URM 85692), L.S. Araujo-Neta & V.R. Coimbra 46NA (URM 85693).
Notes: This species was found as several solitary basidiomata scattered on soil and is characterized by the slender, flexible, and orange basidiomata when fresh, brittle when dry, and hyaline, mostly globose basidiospores. The specimens of C. aurantiaca were placed in a separated, well supported clade (100/1.0) more closely related, but with little support (63/0.58), to Ramariopsis aurantioolivacea R.H. Petersen, C. fusiformis (Sowerby) Corner, C. helvola (Pers.) Corner and C. laeticolor (Berk. & M.A. Curtis) R.H. Petersen. These species have simple, orange basidiomata, but R. aurantio-olivacea has narrower, subglobose to ovate basidiospores (5.4–6.5 x 3.6–5 um) and so far is restricted to New Zealand (Petersen 1988). Clavulinopsis fusiformis, C. helvola and C. laeticolor have been reported in the Neotropics (Petersen 1968; Corner 1950, 1970; Furtado et al. 2016), but C. helvola differs from C. aurantiaca by the angular basidiospores. Clavulinopsis fusiformis (Sowerby) Corner has, on average, larger, globose, subglobose to broadly ovate basidiospores [4.8–7.5(– 9.2) x 4.5–7.2(–9.2) um], while C. laeticolor (Berk. & M.A. Curtis) R.H. Petersen has broadly ellipsoid to subglobose basidiospores (4.3–7.5 x 3.5–6 um). Other species of Clavulinopsis with yellow to orange, simple basidiomata have been reported from the Neotropics. Clavulinopsis aurantiocinnabarina (Schwein.) Corner, however, has hyaline to pale yellow, subglobose basidiospores (5–7.1 x 4–7.1 um), while C. calocera (G.W. Martin) Corner has longer, cylindrical to suballantoid basidiospores (8.5–10 x 4–5 um). Clavulinopsis amoena (Zoll. & Moritzi) Corner presents pale yellow basidiomata and subglobose basidiospores (4–7 x 4–6.5 um) (Petersen 1968; Corner 1950, 1970).
Phylogenetic tree of the Clavulinopsis and Ramariopsis obtained by analyses from rDNA sequences. Taxa with two accession numbers were analyzed by concatenated ITS and partial LSU rDNA; only the partial LSU rDNA was used to analyze the other individuals. Support values (from top) are maximum likelihood (ML) and Bayesian analyses. Sequences obtained in this study are in boldface. Only support values of at least 50 % are shown. The tree was rooted with Clavaria acuta
Clavulinopsis aurantiaca (holotype). a Basidiomata. b, c Hyphae with clamps. d Basidia, one clamped at the base. e Basidia with sterigmata and basidiospores. f Basidiospores with apiculus. Scale bars a = 1 cm, b = 20 um