Corniculariella rhamni W.J. Li, Camporesi & K.D. Hyde, sp. nov.
Etymology: Named after the host genus from which it was collected, Rhamnus.
Saprobic on dead stems of Rhamnus alpinus (Rhamnaceae). Sexual morph: undetermined. Asexual morph: Conidiomata 300–550 µm diam., 200–1200 µm high, yellowish or dark brown to black, pycnidial, solitary to gregarious or confluent, deeply immersed in origin, becoming partly erumpent at maturity, subglobose or subcylindrical to subconical, slightly swollen at the base or level of the locule, narrow towards the apex, unilocular, locule occasionally extending the length of the beak and somewhat enlarged in the basal part, glabrous, beaked, thick-walled, minutely scabrous, lacking an ostiole but dehiscing by an irregular split in the apical wall, or presenting ostiole. Ostiole 200–400 × 55–250 µm, cylindrical to subcylindrical, single, centrally located, with a long neck filled with hyaline hyphae. Paraphyses 200–370 × 2–5 µm, hyaline, filiform, septate, unbranched, developed from the upper region of conidiomata. Conidiomata wall 50–200 µm wide, composed of relatively thick-walled, brown to hyaline cells of textura angularis to textura intricata in the basal part, and a thick-walled, pale brown gradually merging with hyaline cells of textura porrecta in the upper part, and hyaline hyphae forming a textura porrecta to textura angularis in the upper part. Conidiophores 10–30 × 2–5 µm, hyaline, cylindrical, branched, formed from inner layers of the conidiomata. Conidiogenous cells 10–40 × 2–4.5 µm, hyaline, enteroblastic, phialidic, cylindrical to lageniform, indeterminate, discrete or integrate, smooth, thick-walled. Conidia 40–65 × 2.6–5 µm (x = 52 × 4 µm; n = 100), hyaline, fusiform to clavate, tapering toward the base, with a pedicel at base, obtuse at apex, curved, 0–3-septate, mostly1-septate, thick-walled, smooth, guttulate.
Culture characters: Colonies on PDA, yellowish, flattened, with filamentous, sparse, aerial hyphae on the surface, margins lobate, reaching 30 mm diam. after 4 weeks at 25–30°C, reverse yellowish to brown.
Material examined: Italy, Province of Forlì-Cesena, Monte Fumaiolo, on dead aerial branches of Rhamnus alpinus (Rhamnaceae), 11 May 2016, Erio Camporesi, IT2958 (MFLU 16-1329, holotype), ex-type living culture MFLUCC 16-1446 = ICMP 21545; IT2958F (KUN, HKAS 97498), living culture MFLUCC 16-1445; IT2958b (KUN, HKAS 101649), living culture MFLUCC 17-2501.
Notes: Three samples of Corniculariella rhamni (IT2958, IT2958b and IT2958F) were collected from Italy on dead stems of Rhamnus alpinus, of which IT2958 has black, subcylindrcial to subconical conidiomata without an ostiole (Fig. 90 a, e), while IT2958F and IT2958b have yellowish conidiomata with long necked ostioles (Fig. 90 b–d). Phylogenetic analyses based on multi-gene of LSU, ITS and rpb2 sequence data show that these three collections are conspecific with high bootstrap value (Fig. 90). The discrepancy shown here may reflect intraspecific variation. Moreover, according to the multi-gene dataset, the fixed differences in nucleotides among these collections are relatively small and can be found only in rpb2 sequence region (4/1079 bp). Morphologically, C. rhamni fits well within the generic concept of Curniculariella, comparing with other genera of coelomycetes (DiCosmo 1978, Sutton 1980). Corniculariella rhamni shares similar with C. abietis in the form of conidiomata, conidiogenous cells and conidia (DiCosmo 1978), but can easily be distinguished by septation of conidia. Corniculariella rhamni produces 0–3-septate conidia, while C. abietis has 7–8 septate conidia. Corniculariella spina has 0–3-septate conidia (DiCosmo 1978, Illman 1985), but, C. rhamni has yellowish to black conidiomata and smaller conidiomata than the black conidiomata, 500–1500 µm high in C. spina. Furthermore, C. rhamni has fusiform to clavate conidia with a pedicel, whereas, C. spina has falcate, crescentic to sigmoid conidia. Based on its distinct morphology, C. rhamni is introduced as a new species in Corniculariella.
Corniculariella rhamni (MFLU 16-1329, holotype) a–e Appearance of yellowish, dark brown to black conidiomata on the host. f–j Vertical sections of conidioma. k Section of peridium. l–m Conidiogenous cells and developing conidia. n. Paraphyses. o–q Conidia, r Germinating conidium. s–t Cultures on PDA . Scale bars a, e–i = 200 µm, j–k = 100 µm, l–m, o–q = 20 µm, n = 10 µm, r = 100 µm, s–t = 20 mm.
Li WJ, McKenZie EHC, Liu JK, Bhat DJ, Dai DQ, Caporesi E, Tian Q, Maharachcikumbura SSN, Luo ZL, Shang QJ, Zhang JF, Tangthirasunun N, Karunarathna SC, Xu JC, Hyde KD (2020) Taxonomy and phylogeny of hyaline-spored coelomycetes. Fungal Diversity 100: pages279–801.