Acta Phytotaxonomica et Geobotanica

Featured article

Volume 68 (2017) Issue 3 Pages 129-144

Morphological and Molecular Phylogenetic Analyses of Geranium yesoense (Geraniaceae) in Japan

Yuki Wakasugi, Hiroshi Azuma (Present Name: Suzuki), Akiyo Naiki, Sachiko Nishida

Geranium yesoense (Geraniaceae) includes several varieties that are mainly discriminated by two morphological features, namely, the degree of leaf incision and the density of spreading hairs on the sepals, but these features have never been objectively quantified. To clarify whether these features can truly discriminate varieties, we analyzed leaf shape and sepal pubescence, and conducted a molecular phylogenetic analysis using nuclear and chloroplast DNA. Our morphological analyses showed some trends in leaf morphology and density of hairs, but failed to identify any groupings that could be clearly distinguished on the basis of these features. Our molecular analysis recognized G. yesoense as a distinct taxon, but did not support the existence of subgroups within the species. We conclude that G. yesoense must be treated as a single taxon with some tendency toward morphological variation depending on locality and habitat.

Editor’s picks

A paper awarded the Best Paper Prize 2017

Volume 67 (2016) Issue 1 Pages 1-16

Postglacial Lineage Admixture in the Contact Zones of the Two Japanese Deciduous Broad-leaved Tree Species Estimated by Nuclear Microsatellite and Chloroplast DNA Markers

AKITAKA TONO, TAKAYA IWASAKI, AKIHIRO SEO, NORIAKI MURAKAMI

When historically isolated populations meet during postglacial expansion, a mixed distribution of distinct DNA lineages called contact zones is created. The gradual dissolution of the spatial genetic structures in contact zones should be related to differences in pollen and seed dispersal, given no restriction on gene flow by e.g. reproductive isolation. We aimed to clarify effects of pollen dispersal modes on nuclear DNA (nrDNA) genetic structures of two codistributed species with different pollen dispersal modes, by analyzing nuclear microsatellites of the insect-pollinated Magnolia obovata and the wind-pollinated Carpinus laxiflora, which show highly consistent contact zone locations in terms of chloroplast DNA (cpDNA). The genetic structure based on the nrDNA and that based on the cpDNA were concordant in M. obovata, but not so concordant in C. laxiflora . Pollen dispersal ability is higher in the wind-pollinated C. laxiflora than in M. obovata, resulting in the higher estimated pollen/seed migration ratio in C. laxiflora than in M. obovata. Therefore, the extent of postglacial lineage admixture in nrDNA was predominant in C. laxiflora . Our results suggested that differences in pollen dispersal ability may affect the nrDNA genetic structure between co-distributed species with common migration histories in the same area.

Editor’s picks

A paper awarded the Best Paper Prize 2016

Volume 67 (2016) Issue 1 Pages 29-36

Comparative Morphology of Chloroplasts in Podostemaceae Subfamilies Tristichoideae and Weddellinoideae suggests Evolution of Chloroplast Dimorphism

RIEKO FUJINAMI, ISAO YOSHIHAMA, RYOKO IMAICHI

Podostemaceae comprise a unique aquatic angiosperm family. Members of the family grow on rock surfaces of waterfalls and rapids in the tropics and subtropics. Recently, chloroplast dimorphism was reported for 13 species from the majority of clades in the subfamily Podostemoideae. Large chloroplasts with well-developed starch grains and small chloroplasts with few starch grains are located separately in the epidermal cells of roots and shoots. Transmission electron microscopy (TEM) analysis revealed that the large chloroplast is comparable to a typical, ordinary chloroplast, while the small chloroplast does not, but is specialized. To investigate whether chloroplast dimorphism is common in Podostemaceae, we conducted TEM and light microscopy of six species from two subfamilies, Tristichoideae and Weddellinoideae. All samples examined had uniform chloroplasts of the same size. Evaluation of their ultrastructure indicated they had normal grana and starch grains. These findings suggest that chloroplast dimorphism is a trait limited to Podostemaceae subfamily Podostemoideae.

Editor’s picks

A paper awarded the Best Paper Prize 2016

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2018 Volume 69 Issue 2

A New Species, Cerasus kumanoensis from the Southern Kii Peninsula, Japan Toshio Katsuki
Revised Classification of the Species within the Dryopteris varia Complex (Dryopteridaceae) in Japan Kiyotaka Hori, Atsushi Ebihara, Noriaki Murakami
Natural Hybridization between the Endangered Herb Artemisia gilvescens (Asteraceae) and the Common Congener, Artemisia indica var. maximowiczii in Japan Tadashi Yamashiro, Makoto Ogawa, Asuka Yamashiro, Masayuki Maki

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