By Lechat C., Fournier J.
Vol. 11 (2) – 06 April 2019
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Abstract: Pleiocarpon gardiennetii sp. nov. is described and illustrated based on a collection on a dead pyrenolichen, Astrothelium sp. (Trypetheliaceae), in French Guiana. The cylindrocarpon-like asexual morph of this fungus was obtained in culture and a rDNA ITS sequence was likewise obtained from this fungus. Based on morphological characteristics of both asexual and sexual morphs, this fungus belongs to the aggregate formerly known as Neonectria s. l. (Nectriaceae), which is supported by our phylogenetic data. Our phylogenetic analysis places it in the monotypic genus Pleiocarpon, but distinct from P. streliziae, the type species. Pleiocarpon gardiennetii is therefore proposed as a new species; it is characterized by orange red to red ascomata turning purple in 3% KOH and yellow in lactic acid, rough-walled, not collapsing upon drying, with a discoid apex; ascospores are hyaline, echinulate, 9–10 × 4–4.5 µm µm; microconidia in culture are 7–13(–15) × 3.5–5 µm and macroconidia are 1–3-septate and up to 52–55 × 6 µm.
In the course of a survey of fungi in Saül, French Guiana, in August 2018, a nectriaceous fungus was collected on a dead pyrenolichen, Astrothelium sp. Morphological characteristics of the sexual morph and the cylindrocarpon-like asexual morph obtained in culture clearly suggested affinities with genera formerly assigned to Neonectria […]