A new species of Nuphar (Nymphaeaceae), N. submersa, from Tochigi Prefecture, central Japan, is described. Nuphar submersa is characterized by its submerged habit and narrowly oblong-triangular leaves that lack a sinus. It differs from both N. japonica and N. oguraensis in the color of the anthers and fruits. A phylogenetic study based on Amplified Fragment Length Polymorphism (AFLP) fragments showed that both N. submersa and N. oguraensis were sister taxa, but they were well separated phylogenetically.

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Lecanorchis amethystea Sawa, H. Fukunaga & S. Sawa (Orchidaceae) is described from Kochi Prefecture, Japan. Lecanorchis amethystea is similar to L. nigricans Honda, but detailed morphological comparison supports its status as a new species. It is easily distinguished by the following combination of characters: 1) longer stem; 2) longer inflorescence and infructescence, because of longer internodes; 3) yellowish white, narrower sepals and petals; 4) 5-nerved and slightly 3-lobed labellum; 5) bright brown, ascending capsule; 6) column more than half fused with labellum; and 7) column basally pubescent.

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A taxonomic study of the seagrass genus Halophila Thouars concludes that eight distinct taxa, including four new species, occur in Japanese waters. Past literature indicated that the name of H. ovata Gaud. is illegitimate, thus a new species name, H. gaudichaudii J. Kuo, with a description is provided. Halophila major (Zoll.) Miq. has been reinstated to a distinct taxon, with H. euphlebia Mak. as a synonym. The other three new species, H. nipponica J. Kuo, H. mikii J. Kuo, and H. okinawensis J. Kuo are endemic to Japan, while H. gaudichaudii, H. ovalis (R. Br.) Hook. f., H. major, H. minor (Zoll.) den Hartog and H. decipiens Ostenf. are extended from Indo-West Pacific regions to reach their northern distributional boundaries in southern Japan. Halophila okinawensis and H. gaudichaudii are restricted to Ryukyu Islands and H. mikii only occurs in Tanegashima and Yakushima Islands. Halophila nipponica is widely distributed in temperate Japan except for Hokkaido Island, while the tropical H. major has additional colonies confined to Wakayama Prefecture in Honshu and Tokushima and Kochi Prefectures in Shikoku. Typifications, morphological descriptions, habitat and biological information, illustrations and distribution maps are presented for each taxon. Biogeographical distribution of the Japanese species is discussed in relation to the effect of currents.

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Internal transcribed spacer (ITS) region of 18-26S nuclear ribosomal DNA (nrDNA) in 18 species and three subspecies of Pinguicula distributed in the northern hemisphere was sequenced. Based on the ITS results, species in Section Pinguicula were basically well-agreed with the orthodox classification. Although three subspecies of P. longifolia have been described, the present approach showed them to be separate species. The ITS sequences between P. vulgaris and P. bohemica were identical and suggested that the two species could be conspecific as normally treated. Pinguicula alpina did not show any direct relationship with P. ramosa and P. variegata although they have been taxonomically placed in Section Micranthus. The present ITS study suggested that P. villosa, only the species of Section Nana, was closely related to P. ramosa and P. variegata. The northern Pinguicula taxa studied here performed the same seasonal growth pattern, but it was likely as a result of convergent evolution.

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We reviewed the taxonomic status of Picea alcoquiana var. reflexa based on the morphology of cones and other characters that had been previously used to distinguish it from var. alcoquiana. Picea alcoquiana var. reflexa has been distinguished from var. alcoquiana by its reflexed cone scales. Reflexed cone scales from 831 cones from eight populations and two individual trees covering the entire geographic range of P. alcoquiana were categorized into five types. We discovered that cone scale reflection varied among populations and continuously within the species, and therefore could not be used to distinguish var. reflexa from var. alcoquiana. We concluded that P. alcoquiana var. reflexa should not be recognized as infraspecifically distinct.

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The floral and leaf morphology of Ryukyu Pieris were examined to determine the allopatric differentiation among the islands of Yakushima, Amamioshima, Okinawa, and Taiwan. The leaves of P. koidzumiana from Okinawa were narrower than those of other insular plants and were rheophytic, while P. koidzumiana from Amamioshima possessed the wider leaf characteristics of inland plants. Pieris koidzumiana populations from these two islands shared quite large and unconstricted corollas; however, they differed significantly in corolla size. Pieris japonica var. yakushimensis from Yakushima Island and P. taiwanensis from Taiwan had wider and smaller leaves than those of P. koidzumiana, as well as smaller and more constricted corollas. Morphological differentiation of Pieris plants on the Ryukyu Islands and Taiwan can be attributed to ecological differences among the islands, locations in a riverbank or inland habitat, and the presence of anthophilous insect communities on the islands.

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Japonolirion osense Nakai (Petrosaviaceae) is a vulnerable plant of serpentine soils known to occur only on Mt. Shibutsu and Mt. Tanigawa (Gunma Prefecture), and at Toikanbetsu (Hokkaido), Japan. We investigated the clonal structure and genetic differentiation in these populations using amplified fragment length polymorphism (AFLP) analysis. Japonolirion osense reproduces via rhizomes. The AFLP phenotype patterns indicated that genets were about 1-5 m in diameter. Some clones of the plant from the Mt. Shibutsu population had invaded open habitat to about 15 m where erosion from snow had caused landslides. Our population study showed that the populations of J. osense on Hokkaido and Honshu are genetically different.

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