ABSTRACT We studied the South American species of Cortinarius section Thaumasti based on morphological and molecular data. Members of this group can easily be identified in the field because the basidiomata are small and Phlegmacium-like with a bulbous stipe and the universal veil in most species forms a distinct volva at the base of the stipe. The phylogenetic delimitation of the clade was mostly in concordance with the earlier, morphology-based grouping of the South American taxa except that C. chrysophaeus was resolved outside of the clade. Altogether nine species were recognized in the section. Four species, C. chlorophanus, C. coleopus, C. cosmoxanthus, and C. vaginatus, were previously described by other authors, whereas three species, C. chlorosplendidus, C. olivaceovaginatus, and C. subcosmoxanthus, are described here as new. We were able to identify two remaining taxa, but we do not have sufficient morphological data to allow for a formal description. All of the species in C. section Thaumasti form ectomycorrhizal associations with Nothofagaceae. They have been documented from South America and New Zealand. The Patagonian species are considered endemic to the region. A key to the described species is provided.

中文翻译：

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Cortinarius 部分 Thaumasti 在南美 Nothofagaceae 森林

摘要 我们基于形态学和分子数据研究了南美 Cortinarius 节 Thaumasti 物种。该组的成员在野外很容易被识别，因为担子纲很小，类似 Phlegmacium，具有球茎状的叶柄，并且大多数物种的普遍面纱在叶柄的基部形成了一个独特的 volva。除了 C. chrysophaeus 在进化枝之外解析之外，进化枝的系统发育划分主要与南美分类群的早期基于形态学的分组一致。该部分共识别出九个物种。C. chlorophanus、C. coleopus、C. cosmoxanthus 和 C. vaginatus 四个物种之前由其他作者描述过，而 C. chlorosplendidus、C. olivaceovaginatus 和 C. subcosmoxanthus 三个物种在这里被描述为新物种。我们能够识别出两个剩余的分类群，但我们没有足够的形态数据来进行正式描述。C. section Thaumasti 中的所有物种都与 Nothofagaceae 形成外生菌根关联。它们已在南美洲和新西兰被记录下来。巴塔哥尼亚物种被认为是该地区的特有物种。提供了所描述物种的密钥。