The genus Rhytidhysteron is characterised by forming navicular to apothecial hysterothecia, exposing the green, yellow, orange, red, vinaceous or black colours of the hymenium which generally releases pigments in the presence of KOH. The exciple is smooth or striated, the asci bitunicate and ascospores have 1–5 transverse septa. To date, twenty-six Rhytidhysteron species have been described from the Tropics. The present study aims to describe three new species in the Neotropics of Mexico based on molecular methods and morphological features. Illustrations and a taxonomic key are provided for all known species of this genus. Rhytidhysteron cozumelense from the Isla Cozumel Biosphere Reserve, R. esperanzae from the Sierra Juárez, Oaxaca and R. mesophilum from the Sierra Madre Oriental, Hidalgo are described as new species. With the present study, the number of species of Rhytidhysteron known from Mexico is now increased to eight.

中文翻译：

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来自墨西哥的三个新种 Rhytidhysteron（Dothideomycetes、Ascomycota）

Rhytidhysteron 属的特征是形成舟状到 apothecial hysterothecia，暴露处女膜的绿色、黄色、橙色、红色、葡萄色或黑色，通常在 KOH 存在下释放色素。子体光滑或有条纹，子囊和子囊孢子有1-5个横隔。迄今为止，已在热带地区描述了 26 种 Rhytidhysteron。本研究旨在根据分子方法和形态特征描述墨西哥新热带地区的三个新物种。为该属的所有已知物种提供了插图和分类学关键字。来自科苏梅尔岛生物圈保护区的 Rhytidhysteron cozumelense、来自瓦哈卡州华雷斯山脉的 R. esperanzae 和来自伊达尔戈东部马德雷山脉的 R. mesophilum 被描述为新物种。通过目前的研究，