Kenji Suetsugu

At a Japanese museum, a poster for the rediscovered fairy lantern Thismia kobensis read, “Hello—after 30 years, I’m back.” The message made tangible an idea that had guided the description: naming a species can open, rather than close, its biological story. Drawing on four recently named Japanese plants, I show how names and diagnoses supported rediscovery, enabled separate conservation assessment of an overlooked lineage, connected scattered observations, and preserved a record of shared discovery. A name does not guarantee attention or protection. It can nevertheless give evidence, institutions, and care a shared address.

Societal Impact Statement: Conserving rare plants requires understanding the ecological interactions that enable their reproduction. Most studied Cypripedium species are pollinated by bees, but the pollinators of many slipper orchids remain undocumented. We show that Cypripedium yatabeanum is pollinated by female aphidophagous hoverflies despite sharing broadly similar floral architecture with the closely related, bee‐pollinated Cypripedium guttatum . This contrast indicates that pollinators cannot be inferred from floral structure alone. Conservation strategies should therefore protect not only orchid populations but also their pollinators and the surrounding resources that sustain them, including flowering plants for adults and aphid‐rich habitats for larvae. Summary: A deceptive flower must attract visitors and guide them into contact with its reproductive organs. This mechanical control is most pronounced in slipper orchids, whose pouch‐like labella trap insects and force them out through narrow basal apertures. Although most studied Cypripedium species are bee‐pollinated, fly pollination has been reported repeatedly. We investigated the previously undocumented pollination biology of Cypripedium yatabeanum , a member of section Bifolia with a pitcher‐shaped labellum, broad dorsal opening, glossy rim, and downward‐curved, ridged staminode. This architecture resembles that of the closely related, bee‐pollinated Cypripedium guttatum and several hoverfly‐pollinated Paphiopedilum species. Female Melanostoma interruptum and Melanostoma mellinum were legitimate pollinators. They hovered around flowers, landed on the staminode or adjacent glossy surfaces, and often slipped from the staminode into the pouch. Trapped flies escaped through basal apertures, contacting the stigma before acquiring a sticky pollen mass from an anther. A larger fly entered but could not escape, consistent with size‐dependent mechanical filtering. Exploratory scent analysis identified β‐myrcene, geraniol, and p ‐cresol as the main volatiles in the DVB/CAR/PDMS profile. A PDMS fiber also detected a trace of ( E )‐β‐farnesene. Cypripedium yatabeanum is therefore pollinated by female Melanostoma hoverflies through a Paphiopedilum ‐like trap. Its yellowish‐green display, prominent staminode, and glossy surfaces suggest anther/pollen and nectar mimicry, with volatiles as candidate supplementary signals. Comparison with bee‐pollinated C. guttatum shows that broadly similar trap architecture can accommodate different pollinator guilds, with divergence in attraction signals as a possible explanation.

Many photosynthetic orchids combine photosynthesis with fungal carbon acquisition, yet the isotopic relationships between orchids and their fungal partners remain poorly resolved. Direct stable isotope analysis of pelotons and extraradical fungal tissues can refine fungal baselines and clarify nutritional dynamics in orchid mycorrhizas. We investigated Cremastra appendiculata , a photosynthetic orchid with contrasting mycorrhizal states, by comparing fungal communities between individuals with and without coralloid rhizomes and analyzing the δ ¹³ C and δ ¹⁵ N values of leaves, protocorms, coralloid rhizomes, pelotons, Psathyrellaceae rhizomorphs, dead wood, and autotrophic reference plants. Psathyrellaceae-associated individuals were strongly enriched in ¹³ C relative to autotrophic reference plants, indicating substantial acquisition of fungal carbon, whereas rhizoctonia-associated individuals exhibited little ¹³ C enrichment and appeared predominantly autotrophic. Leaf δ ¹⁵ N values exceeded those of the associated fungal tissues in both states, suggesting plant-mediated ¹⁵ N enrichment during nitrogen assimilation and allocation to leaves. Coralloid rhizome pelotons did not differ detectably in δ ¹³ C or δ ¹⁵ N between digestion stages. Pelotons resembled extraradical Psathyrellaceae rhizomorphs in δ ¹⁵ N but had higher δ ¹³ C values, indicating tissue-specific carbon isotope baselines. Psathyrellaceae tissues were less ¹³ C enriched than fungal tissues reported from fully mycoheterotrophic orchids associated with wood-decaying fungi. These results support contrasting nutritional states in C. appendiculata : a predominantly autotrophic, rhizoctonia-associated state and a more fungus-dependent, Psathyrellaceae-associated state. The fungal isotope pattern raises the possibility that bidirectional carbon transfer persists even in the latter state. Determining whether the orchid transfers carbon to its fungal partners requires controlled culture or tracer experiments.

The evolutionary transition from autotrophy to full mycoheterotrophy is often viewed as a progressive loss of photosynthetic capacity, yet comparative studies of closely related leafless orchids that retain residual photosynthesis remain scarce. The Cremastra appendiculata species complex provides a valuable system for testing whether dependence on fungal carbon varies among leafless species. We compared the nutritional modes of two closely related leafless orchids, Cremastra aphylla and C. saprophytica , at flowering and fruiting using natural‐abundance stable isotope analyses and measurements of chlorophyll concentration and fluorescence. Both species retained functional, albeit limited, photosynthetic capacity. From flowering to fruiting, chlorophyll concentrations and the maximum quantum yield of photosystem II increased, whereas δ ¹³ C values decreased, a pattern consistent with enhanced photosynthetic capacity during reproductive development. However, C. aphylla consistently showed greater ¹³ C enrichment relative to autotrophic reference plants and had a significantly lower chlorophyll concentration during flowering than C. saprophytica , indicating greater dependence on fungal carbon. These results demonstrate that leaflessness does not necessarily imply full mycoheterotrophy and, more importantly, that dependence on fungal carbon can differ even between closely related leafless species. Together with developmental‐stage‐dependent changes within each species, these interspecific differences suggest that the transition from partial to full mycoheterotrophy can proceed through multiple incremental steps even after leaflessness has evolved.

Detecting partial mycoheterotrophy in green plants remains challenging, particularly in associations with arbuscular mycorrhizal (AM) or rhizoctonia fungi, because natural-abundance stable isotope patterns often provide limited diagnostic resolution in these systems. We tested whether fatty acid composition, widely used to infer trophic relationships in animal and soil ecology, provides complementary evidence of fungal carbon acquisition by plants. We characterized fatty acid profiles of 21 autotrophic reference plants, six partially mycoheterotrophic plants, and 17 fully mycoheterotrophic plants associated with AM, ectomycorrhizal, or saprotrophic fungi. In expanded analyses, we additionally examined three individuals each of the rhizoctonia-associated orchid Goodyera biflora and the presumed autotrophic AM plant Trillium camschatcense with marked ¹³ C enrichment, together with six co-occurring autotrophic reference plants. Fatty acid composition differed significantly among the three nutritional groups. Increasing mycoheterotrophic dependence was associated with decreasing relative abundance of 18:3n-3 and increasing relative abundance of 18:2n-6, which is widely used as a fungal biomarker in soil ecology. Partially mycoheterotrophic plants occupied an intermediate position in ordination space, and all pairwise group comparisons were significant. Differentiation remained significant after exclusion of 18:3n-3 and 16:3n-3 and renormalization of the remaining components, indicating that chloroplast-associated fatty acids alone did not drive the pattern. Goodyera biflora resembled partially mycoheterotrophic orchids, whereas T. camschatcense resembled autotrophic references. Fatty acid profiling may therefore complement stable isotope analysis in assessments of partial mycoheterotrophy. The profiles likely reflect metabolic remodeling, incorporation of fungal-derived carbon into newly synthesized plant lipids, or both, although some retention of intact fungal lipids cannot be excluded.