Relictithismia: An underground fairy lantern

Abstract

Societal Impact Statement The discovery of a new genus within the family Thismiaceae, known as fairy lanterns, marks a significant scientific milestone in Japan, a country renowned for its botanical research. The unearthing of a new genus, especially in a well‐documented flora like Japan, is both rare and monumental. Unlike other fairy lanterns that bloom under leaf litter and can be easily overlooked, the new genus and species, Relictithismia kimotsukiensis, often does not even emerge above the surface of the soil when flowering. This captivating characteristic not only enriches our knowledge of botanical diversity but also emphasizes the importance of preserving natural habitats that harbor such rare species. Summary The family Thismiaceae, known as “fairy lanterns”, is distinguished by its urn‐ or bell‐shaped, glasswork‐like flowers with basally fused tepals and its dependence on specific fungi for carbon. A new genus and species, Relictithismia kimotsukiensis, has been discovered in southern Japan. This species is notable for its unique anther‐stigma contact, hitherto unreported in the other Thismiaceae. Unlike typical fairy lanterns that bloom just above the leaf litter, Relictithismia often flowers beneath it. The underground habit is potentially associated with self‐pollination. The discovery of Relictithismia enhances our understanding of evolutionary pathways within the Thismiaceae, as it possesses characteristics previously thought to be unique to Thismia (the annulus with drooping stamens) as well as traits found in other genera (free stamens without expanded connectives). This paper reviews the morphology, ecology, and evolutionary history of Relictithismia, offering insights into the peculiarities of these enigmatic plants.

Keywords

• arbuscular mycorrhiza
• East Asia
• endemic species
• fairy lantern
• mycoheterotrophy
• Thismiaceae