Leitneria floridana, a dioecious shrub indigenous to North America, was recently transferred from its own family Leitneriaceae (usually placed in 'Amentiferae') to the family Simaroubaceae (Sapindales). Its staminate inflorescence is catkin-like, bearing 40-50 large bracts arranged in a 5/8 phyllotaxis on the axis. In each bract axil, a varying number of stamens (usually 10) are produced. They have been considered to represent a (one- to) three-flowered cymule instead of a single flower. In reviewing the limited evidence for the presence of the cymule and the revised familial position of the species, I re-examined the structure of the staminate inflorescences by analyzing serial microtome sections. The results confirmed that the staminate inflorescence of Leitneria is a reduced form of a thyrse consisting of many cymules, and that each cymule consists of one central and two lateral flowers (florets). Each flower has four stamens arranged in a cross-like configuration, in contrast to the previously considered diagonal configuration. One or more stamens, however, may be lacking in each flower, particularly in the lateral flowers, resulting in a varying number of stamens in the bract axil.

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Veronicastrum noguchii K. Uehara, K. Saiki & T. Ando (Plantaginaceae), from Chiba Prefecture, Japan, is described as new. It is similar to V. villosulum (Miq.) T. Yamaz. in having a subglobose inflorescence, but differs in having recurved hairs on the stem, the leaf base cordate or occasionally truncate, the leaf margin crenate, the leaf surface sparsely pilose, bracts sparsely pilose and narrowly oblong to ovate, and narrowly triangular to linear subglabrous calyx lobes.

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Aridarum embalohense H. Okada & Tsukaya (Araceae: Schismatoglottideae), a new species from Betung Kerihun National Park, West Kalimantan, Indonesia, is described and illustrated.

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Morphologically intermediate plants between Arisaema tosaense and A. undulatifolium subsp. uwajimense were recently found in Ehime and Kochi prefectures, Shikoku, Japan. The putative hybrids have the reproductive characteristics of A. tosaense, but purplish-dark brown, short pseudostems similar to A. undulatifolium subsp. uwajimense. Molecular analysis of nuclear ribosomal DNA (nrDNA) internal transcribed spacer (ITS) region using PCR-RFLP indicates that these putative hybrids have a combined pattern of the two putative parental species. The chloroplast DNA (cpDNA) trnL intron sequences of all the putative hybrids and A. tosaense were identical. The results suggest that the plants are hybrids between A. tosaense and A. undulatifolium subsp. uwajimense and were formed by gene exchange via pollen grains transferred from A. undulatifolium subsp. uwajimense to A, tosaense.

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In our previous studies, two independent entities within Pedicularis chamissonis Steven (the Northern type and the Central Honshu type) were revealed from an analysis of genetic, morphological and ecological data. Based on relevant taxonomic literature and specimens of P. chamissonis, we propose the revival of the name P. japonica Miq. for the plants of the Central Honshu type and P. chamissonis sensu stricto for the Northern type.

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Sphagneticola trilobata (L.) Pruski (Asteraceae), considered to be among the world's worst invasive alien species, is indigenous to tropical America, but is now widely distributed in tropical and subtropical regions worldwide. In contrast to its vigorous vegetative reproduction, S. trilobata is thought to produce few fertile fruits. In this study, we investigated cypsela production in S. trilobata plants naturalized in the subtropical Ryukyu Archipelago, Japan, and assessed the viability of cypselas after exposure to seawater. Plants of S. trilobata produce an average of 7.8 cypselas per capitulum with a germination rate of more than 80%. Cypselas of S. trilobata showed high buoyancy in seawater and retained viability after exposure to seawater for 90 days. For preventive management of this species, potential seawater dispersal of cypselas, in addition to vegetative reproduction, should be considered.

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