A brackishwater green macroalga collected from a small watercourse along the shore of Chichijima island, Ogasawara Islands, Japan was identified as Ulva kanagawae V.Carneiro, N.T.Martins & Cassano (Ulvaceae, Ulvophyceae) using the rbcL and tufA DNA sequences. Morphology of the alga from the Chichijima Island agrees with the original description of U. kanagawae in having unique twisted spirally and coiled, compressed, narrow ribbon-like thalli (less than 2 mm in width), profuse branching in the basal region, and multiseriate apices of the branches. This species, originally described in 2023 from São Paulo, Brazil, had not previously been recorded from the Pacific region.

Arachniodes hiugana is an endangered fern in Japan. This study demonstrates that this rare fern is a diploid hybrid of A. hekiana and A. nipponica based on plastid rbcL phylogeny, ploidy analyses, MIG-seq data and morphological characteristics.

Potamogeton ×angustifolius (Potamogetonaceae), an aquatic hybrid species, was discovered in a flood-control reservoir in Tochigi Prefecture, Japan. This site represents only the second known locality of this species in Japan and the first documented case of its emergence from the soil seed bank. DNA analyses of chloroplast (trnT–F, atpB–rbcL) and nuclear (ITS) regions confirmed that this population has P. lucens as the maternal parent and P. gramineus as the paternal parent. This parentage indicates that the population constitutes a reciprocal hybrid relative to the previously reported population in Aomori Prefecture. Terrestrial forms were also observed, a feature likely advantageous under the fluctuating water levels characteristic of the reservoir. These findings highlight the potential for creating new reservoirs to promote the regeneration of rare aquatic plant species.

A new species, Impatiens kennedyensis S.Akiyama & Nob.Tanaka (Balsaminaceae), from Chin State, Myanmar is described and illustrated. Impatiens kennedyensis is similar to I. arguta Hook.f. and I. yingjiangensis S.Akiyama & H.Ohba, but differs in the narrowly oblong-ovate distal lobe with an acute apex of the lateral united petals, and also from the former in the long peduncle and from the latter in the bucciniform lower sepal. A comparison table of I. kennedyensis and similar species is provided.