Fungi play vital roles in ecosystems as endophytes, pathogens and saprobes. The current estimate of fungal diversity is highly uncertain, ranging from 1.5 to 12 million, but only around 150,000 species have been named and classified to date. Since the introduction of DNA based methods for species identification, the number of newly described taxa has increased from approximately 1000 to around 2000 yearly. This demonstrates the importance of DNA based methods to identify and distinguish species, especially cryptic species. Many novel species from recent studies have been found in historically understudied regions and habitats, but these still represent only a small percentage of the estimated species. In this paper, we examine 16 genera from the top 40 most speciose genera as listed in Species Fungorum as case studies to examine the diversity of taxa in each genus. The genera treated herein are Cercospora, Diaporthe, Meliola, Passalora, Phyllachora, Phyllosticta, Pseudocercospora, Ramularia (ascomycetes) and Cortinarius, Entoloma, Inocybe, Marasmius, Psathyrella, Puccinia, Russula, Uromyces (basidiomycetes). We critically evaluate the number of species in these genera and correlate these numbers with the number of entries in GenBank. We introduce 18 new species Apiospora multiloculata, Candolleomyces thailandensis, Cortinarius acutoproximus, Cortinarius melleoalbus, Cortinarius pacificus, Cortinarius parvoacetosus, Diaporthe guizhouensis, Entoloma pseudosubcorvinum, Inocybe meirensongia, Marasmius albulus, Marasmius obscuroaurantiacus, Meliola camporesii, Phyllachora siamensis, Phyllosticta doitungensis, Picipes yuxiensis, Pseudocercospora vignae, Puccinia maureanui and Russula inornata. We also introduce a new record of Candolleomyces cladii-marisci and Inocybe iringolkavensis. We discuss the genera Colletotrichum and Pleurotus that are speciose, but do not occur in the top 40. We hypothesize whether there might be more species in these genera and discuss why these genera have some of the largest number of species.

真菌作为内生菌、病原体和腐生菌在生态系统中发挥着至关重要的作用。目前对真菌多样性的估计高度不确定，从 1.5 到 1200 万种不等，但迄今为止只有约 150,000 个物种被命名和分类。自从引入基于 DNA 的物种鉴定方法以来，新描述的类群数量已从每年约 1000 个增加到约 2000 个。这证明了基于 DNA 的方法对于识别和区分物种，尤其是神秘物种的重要性。最近的研究在历史上未被充分研究的地区和栖息地中发现了许多新物种，但这些仍然只占估计物种的一小部分。在本文中，我们以真菌物种中列出的前 40 个物种最丰富的属中的 16 个属作为案例研究，以检查每个属中类群的多样性。本文处理的属是尾孢属、土霉属、楝属、帕萨洛拉属、叶霉属、叶霉属、假尾孢属、枝孢菌属(子囊菌纲)和Cortinarius属、Entoloma属、Inocybe属、 Marasmius属、Psathyrella属、柄锈菌属、红菇属、尿霉菌属(担子菌纲)。我们严格评估这些属中的物种数量，并将这些数字与 GenBank 中的条目数量相关联。我们引进了18个新种Apiospora multiloculata、Candolleomyces thailandensis、Cortinarius acutoproximus 、 Cortinarius melleoalbus 、 Cortinarius pacificus 、 Cortinarius parvoacetosus 、 Diaporthe guizhouensis、Entoloma pseudosubcorvinum、Inocybe meirensongia 、 Marasmius albulus 、 Marasmius obscuroaurantiacus 、 ola Camporesii、Phyllachora siamensis、Phyllosticta doitungensis 、 Picipes yuxiensis、Pseudocercospora vignae、Puccinia maureanui和Russula inornata。我们还介绍了Candolleomyces cladii-marisci和Inocybe iringolkavensis的新记录。我们讨论了炭疽菌属(Colletotrichum)和侧耳属 (Pleurotus)，它们种类繁多，但未出现在前 40 名中。我们假设这些属中是否可能有更多的物种，并讨论为什么这些属拥有数量最多的物种。