Multifaceted obscurity of Thismia abei (Thismiaceae): A fairy lantern with the protologue long disregarded in practice

Societal Impact Statement: Tiny, leafless fairy lanterns are easily overlooked on the forest floor. Thismia abei, endemic to Japan, persists in small, unstable populations and is listed nationally as Critically Endangered. Our recent work has revealed another, less obvious form of obscurity. The original source of the scientific name has long been cited incorrectly because a later, more widely read academic account displaced an earlier, valid description in a local periodical that some taxonomists dismissed as nonacademic. The case of T. abei is not unique; many similar works were likely treated in the same way. This example underscores the importance of careful nomenclatural study and better access to regional publications so that plant diversity is accurately documented and properly recognized. Summary: Thismia abei is a minute, mycoheterotrophic plant that emerges above the leaf litter in summer. Here, we present a comprehensive review of T. abei by integrating recent findings on its morphology, phylogenetics, ecology, and nomenclatural history. Phylogenetic analyses place T. abei among the early-diverging lineages of the Old World Thismia clade, and current taxonomy assigns it to Thismia sect. Labiothismia. Its stamens are united into a tube along part of their length, although they were previously regarded as free. This misinterpretation has hindered comparisons between Old World and New World lineages. The species exhibits high mycorrhizal specificity and is associated primarily with two Rhizophagus virtual taxa (Glomeraceae). The fungus gnat Bradysia atracornea (Sciaridae) has been observed visiting its musty-scented flowers, consistent with the hypothesis that some fairy lanterns exploit fungus-associated cues. Beyond its biological elusiveness, T. abei also has an obscure nomenclatural history. In a Japanese academic climate in which influential botanists shaped prevailing views of what counted as effective publication, a later and more prominent account became the standard citation for the name, obscuring the earlier protologue that had been effectively published in a regional periodical. This case suggests that substantial taxonomic information remains hidden in regional Japanese publications. In addition, the publication history of T. abei, involving collaboration between a local naturalist, Chikaichi Abe, and a professional botanist, Yoshiyuki Akasawa, illustrates how such partnerships can bring overlooked plants to scientific attention and foreshadows key features of modern citizen science.