The northernmost limit of distribution of Quercus serrata is on Hokkaido, where fragmented populations occur from the southwestern foothills of the Hidaka Mountains to the Ishikari Plain with an additional isolated population on the Oshima Peninsula. These northern marginal populations are considered to be the result of past vegetational shifts, but the genetic relationships are not fully understood. In this study, we used 11 nuclear SSR loci to genotype 667 individuals from 11 populations of Q. serrata in Hokkaido and six populations from the Tohoku region of Honshu. Total genetic diversity in Hokkaido (H_E = 0.693) did not differ from Tohoku (H_E = 0.669). The population differentiation in Hokkaido (G’ _ST = 0.097) was not significantly different from that of Tohoku (G’ _ST = 0.090). The STRUCTURE analysis distinguished four regional clusters of Q. serrata; the Pacific side of Tohoku, the Japan Sea side of Tohoku, the northernmost region, and the Oshima Peninsula. The findings indicate two ancestral origins from the Pacific and Japan Sea coasts of Tohoku in the Hidaka region. The results from principal coordinate analyses indicated that the isolated population on the Oshima Peninsula is more related to the populations on Hokkaido than to the Tohoku populations.

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A species of Podostemaceae discovered in 1963 in Hong Kong was identified as Cladopus nymanii s.l. or C. austrosinensis. No additional specimens were subsequently collected. Consequently, the identification has remained uncertain and it was thought that the plants may have been extirpated in Hong Kong. Half a century later, a species of Cladopus was discovered in a semi natural habitat. Comparison of the morphology and a molecular phylogenetic analysis indicated that it was Cladopus fukienensis. It remains to be ascertained whether it also grows in natural habitats, and if it is the only species of Cladopus in Hong Kong.

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Cytological observations of the mitotic chromosomes of Dryopteris formosana and D. varia (Dryopteridaceae) in Taiwan are reported. Only the triploid apogamous cytotype has been reported from D. formosana. This is the first report of a diploid sexual type of D. formosana. Counts of spore numbers per sporangium of herbarium specimens to presume the reproductive mode in these two species revealed that both sexual and apogamous types of D. formosana and D. varia are widely distributed in Taiwan. Although the sexual type of D. formosana occurs at relatively lower elevations than the apogamous type, such differentiation between cytotypes was not observed in D. varia. It is important to understand diploid sexual types to be able to explain variation in apogamous species, because sexual cytotypes should be the source of the variation observed in apogamous cytotypes.

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Polyalthia gracilicolumnaris H.Okada, Tsukaya & M.Suleiman (Annonaceae), a new species from Imbak Canyon Conservation Area, Sabah, Malaysia, is described and illustrated.

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A new species, Trigonostemon honbaensis Tagane & Yahara (Euphorbiaceae), sp. nov., from Hon Ba Nature Reserve in Khanh Hoa Province, southern Vietnam, is described and illustrated. DNA barcoding data of the rbcL and matK regions is provided. Trigonostemon honbaensis is most similar to T. longifolius Baill. ex Müll.Arg., but distinguished by its less hairy leaves, truncate leaf base (attenuate to obtuse in T. longifolius), larger petals, shorter staminal column, and anthers lacking appendages.

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A blackish brown color is a feature of the mycoheterotrophic orchid Gastrodia pubilabiata. Here, we report a new form of G. pubilabiata with a tinge of red color. A total of ten plants showed a reddish plant body, and this phenotype seems to be stable in two localities. Based on analyses of plant morphology, distribution and pigment, together with color identification using the Munsell color order system, we describe the reddish plants as G. pubilabiata f. castanea.

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During recent field surveys in the northern Ryukyus and herbarium investigations, I found several previously unknown populations of two mycoheterotrophic and cleistogamous orchids, Gastrodia takeshimensis and G. flexistyloides (Orchidaceae). They were previously considered to be endemic to Takeshima, Kagoshima Prefecture. Given that the continued discovery of new species and range extensions for known species of Gastrodia have been made from only a limited number of surveys in a small selection of sites, it is likely that more extensive surveys in the Ryukyu Islands during the flowering season could reveal much more precise data regarding the diversity and distribution of the species of Gastrodia.

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Lasianthus giganteus Naiki (Rubiaceae), first found in Cambodia, was recently discovered in central Vietnam and southern Thailand. We describe the floral morphology of this species for the first time.

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Kiyotaka Hori, Yasuyuki Watano and Noriaki Murakami. 2016. Hybrid Origin of the Apogamous Fern Dryopteris hondoensis (Dryopteridaceae). Acta Phytotaxonomica et Geobotanica 67 (3): 133–146.

Miyako Koizumi and Hidetoshi Nagamasu. 2016. Two New Species and Notes on Bornean Praravinia (Rubiaceae). Acta Phytotaxonomica et Geobotanica 67 (3): 175–184.

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