Japan has 16 native species of the genus Hosta Tratt. (Asparagaceae). A recent study on Hosta based on field surveys and molecular phylogenetic analyses resulted in the discovery of six unknown taxa in Kochi Prefecture, Shikoku Island, southwestern Japan. We aimed to identify these unknown taxa. Therefore, we constructed a finely resolved phylogeny for 320 Hosta samples collected from the Honshu, Shikoku, and Kyushu Islands using multiplex inter-simple sequence repeat genotyping by sequencing (MIG-seq). Based on this phylogenetic analysis and related morphological observations, we describe five new species, H. longipedicellata sp. nov., H. minazukiflora sp. nov., H. polyneuronoides sp. nov., H. samukazemontana sp. nov., and H. takiminazukiflora sp. nov. and one new subspecies, H. takiminazukiflora subsp. grandis subsp. nov. In addition, we propose two new status assignments, H. tardiva subsp. densinervia comb. and stat. nov. and H. scabrinervia stat. nov. We also propose classifying H. kikutii var. tosana as a species, H. tosana. Further studies that combine MIG-seq with careful morphological observations are needed for Hosta plants on all Japanese islands, which may result in the discovery of even more undescribed species.

Leptochilus ornithopus T. Fujiw. & B.H. Quang (Polypodiaceae, Polypodiales) is described as a new species, based on integrated evidence from phylogenetic and morphological examinations. The new species is most similar to L. digitatus and L. longipes but distinguished from both by its having ovate rhizome scales, narrowly cuneate and gradually reduced lamina base, narrowly lanceolate lateral lobes of lamina which are widest at proximal 1/3 or base, and the sori at an angle of 31–38(–40) degree with the midrib.

Thirty angiosperm species in 20 families, collected in Nam Kading National Protected Area, are recorded in Laos for the first time. Because the flora of Nam Kading is rich in endemic species, the area represents one of the core sites of plant biodiversity in Laos. To elucidate the plant diversity accurately, further intensive floristic surveys are required.

A new species, Goniothalamus flagellistylus Tagane & V. S. Dang, sp. nov. from Hon Ba Nature Reserve in Khanh Hoa Province, South Vietnam is described and illustrated. This species is most similar to Goniothalamus tortilipetalus M.R.Hend., but distinct in having 308–336 stamens (vs. ca. 170–260) and ca.120 carpels (vs. ca. 50–100) per flower, and Stigma and pseudostyles ca.8.5 mm (vs. 4–4.5 mm) long.

The family Thismiaceae, known as “fairy lanterns” for their urn- or bell-shaped flowers with basally fused tepals, consists of non-photosynthetic flowering monocots mainly in tropical regions, extending into subtropical and temperate areas. Here, we propose a new mycoheterotrophic genus, Relictithismia Suetsugu & Tagane (Thismiaceae), with its monotypic species Relictithismia kimotsukiensis Suetsugu, Yas.Nakam. & Tagane from Kimotsuki Mountains in the Osumi Peninsula, Kagoshima Prefecture, Kyushu Island, southern Japan. Relictithismia resembles Haplothismia Airy Shaw in having a cluster of tuberous roots, a feature previously observed only in this genus within the family Thismiaceae. However, it differs in having solitary flowers (vs. 2–6-flowered pseudo-raceme in Haplothismia), anther thecae largely separated (vs. connate), and the presence of an annulus (vs. absent). Additionally, Relictithismia differs from the geographically overlapping genus Thismia Griff. in its stamen structure and the position of the annulus. In Relictithismia, the stamens lack connectives, and its free filaments arise from the annulus located inside the perianth mouth, while in Thismia, the stamens typically have connate connectives, forming a staminal tube pendulous from the annulus located at the mouth of the floral tube. Our morphological and phylogenetic data indicated that R. kimotsukiensis holds an early-diverging position within the family, situated outside the Old World Thismia clade. This paper offers an extensive description and color photographs of R. kimotsukiensis, complemented by notes on its phylogenetic relationship and evolutionary history.

Mycoheterotrophic orchids depend completely on mycorrhizal fungi for their supply of carbon. The life-history traits of mycoheterotrophic plants (MHPs) can differ according to the characteristics of the associated mycorrhizal fungi. We compared the life-history strategies of two mycoheterotrophic orchids associated with wood- and leaf litter-decaying fungi over a maximum of six years of field monitoring. Seventy percent of the aboveground stems of Erythrorchis altissima, associated with wood-decaying fungi, disappeared from the host wood within two years after tagging, likely due to nutrient depletion. In contrast, Gastrodia confusa, associated with leaf litter-decaying fungi, occurred continuously (18 to 108 fruiting stalks) every year within a small-scale plot (12 × 45 m) for six years through seed and clonal propagation. Our results support the idea that mycoheterotrophic orchids associated with wood-decaying fungi disappear from their habitats due to nutrient depletion after their host wood has mostly decayed, while mycoheterotrophic orchids associated with leaf litter-decaying fungi can survive in small-scale habitats where substantial leaf fall regularly occurs to sustain the associated fungi. Our study provides basic information about a unique life-history strategy in MHPs associated with saprotrophic fungi and an understanding of the variation in life-history strategies among MHPs.