Dioscorea (Dioscoreaceae), a morphologically diverse genus, consists of more than 600 species distributed worldwide. Recent molecular and morphological analyses allowed us to recognize two subgenera, Dioscorea and Helmia, and 19 Old World species groups (sections) in subgenus Helmia. In this paper we present a diagnostic key and taxonomic treatment for the subgenera and sections, including D. sect. Tamus (stat. nov.) and four new sections; Afroborderea, Perennia (validated here), Pseudoshannicorea and Pseudostenophora. Lectotype species for eleven sections; Enantiophyllum, Illigerastrum, Lasiophyton, Macrocarpaea, Macropoda, Madagascarienses, Orientali-asiaticae, Rhacodophyllum, Shannicorea, Stenophora and Syntepaleia, are also designated.
Fifteen new species of angiosperms, Ilex bidoupensis, I. hongiaoensis (Aquifoliaceae), Mastixia hongiaoensis (Cornaceae), Daphniphyllum hongiaoense (Daphniphyllaceae), Platea hongiaoensis (Icacinaceae), Neolitsea bidoupensis, N. hongiaoensis (Lauraceae), Nyssa bidoupensis, N. hongiaoensis (Nyssaceae), Eriobotrya hongiaoensis, Prunus hongiaoensis (Rosaceae), Luvunga hongiaoensis (Rutaceae), Illicium viridiflorum (Schisandraceae), Symplocos hongiaoensis (Symplocaceae) and Alpinia hongiaoensis (Zingiberaceae), from the Hon Giao area in Bidoup-Nui Ba National Park, Lam Dong Province, in the southern highlands of Vietnam, are described and illustrated.
Saxifraga fortunei sensu lato (Saxifragaceae) varies greatly in morphology and includes many infraspecific taxa. As many as five varieties have been recognized in western Japan, although their discrimination based on leaf size or leaf shape, such as cuneate base or degree of lobing is often difficult to determine due to continuous variation. To quantify the variation in leaf morphology, especially focusing on cuneate and parted leaves, 259 samples from 87 populations in western Japan were subject to principal component analysis. Additionally, developmental changes in plants from three selected populations were examined. The findings revealed that plants with parted leaved (var. suwoensis) were discriminated from plants with cuneate and normal leaves, while plants with cuneate leaves (var. obtusocuneata) were within the range of variation of var. fortunei. Leaf shape changes from cuneate to truncate or cordate during the transition from a vegetative state to the flowering state. Cuneate forms usually occurred in sterile plants, but also on flowering plants even within a population. This characteristic was less useful for recognizing var. obtusocuneata. Populations with parted (long lobed) leaves as well as those with cuneate leaves usually grow along streams, confirming that phenotypes are the result of adaptive differentiation toward becoming facultative rheophytes, as previously suggested.
A new color variant of Lecanorchis japonica Blume, L. japonica f. lutea (Orchidaceae), is described from Kagoshima and Chiba prefectures, Japan. Lecanorchis japonica f. lutea differs from L. japonica f. japonica only by its brilliant yellow coloration. Additionally, L. japonica f. lutea is superficially similar to L. hokurikuensis f. kiiensis but differs in having widely open flowers (vs. barely open flowers) and a nearly entire column wing (vs. apparent projections below column wing).