Acta Phytotaxonomica et Geobotanica

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Volume 73 (2022) Issue 1 Pages 19-33

Seed Morphology and Dispersibility of Orchids in Warm Temperate Japan

Hiroki Nakanishi

Flowering and dispersal phenology, characteristics of fruits, seed shape, and seed and embryo sizes were studied in orchids in the warm temperate zone of Japan. Anemochorous potential was estimated based on the ratio of seed length to embryo length. The data obtained were compared among different life forms: epiphyte, saprophyte (myco-heterotroph), summer green terrestrial and evergreen terrestrial or- chids. The epiphytes, which had the smallest seeds, had the poorest dispersibility. On the other hand, the saprophytes, which had elongated seeds, had excellent dispersibility. Seed size and dispersibility of ter- restrial orchids ranged between those of epiphytes and saprophytes. Most epiphytes had hygroscopic trichomes, which contributed to the release of the seeds from capsule. It was clarified that seed morphol- ogy and dispersal mechanisms in orchids were closely related to their life form.

Editor's pick

A paper awarded the Best Paper Prize 2023

Volume 73 (2022) Issue 2 Pages 107-118

Biosystematic Studies of Carex (Cyperaceae) II. Carex nasuensis, a New Species from Japan

Kotaro T. Takahashi, Tatsunari Noguchi, Jiro Oda, Shizuka Fuse, Minoru N. Tamura

A new species of Carex sect. Paniceae (Cyperaceae) is described based on specimens from Honshu, Japan, and named C. nasuensis. It is similar to C. filipes and C. macroglossa, but differs from C. filipes in having pale green staminate scales, pale brown basal part of the sheath and perigynia tapering to the apex, and from C. macroglossa in having fewer (2–4) perigynia per pistillate spike, pistillate spikes more distantly located on the culm (3.6–7.5 cm between the uppermost and second uppermost pistillate spikes), flat or slightly elevated surface of the epidermal cells of the perigynium (without any conspicuous projections) and an achene epidermal cell surface with a small conical silica deposit surrounded by a marginal depression. A phylogenetic analysis based on the combined data set of plastid regions atpB–rbcL, rpl16–rpl16–rps3, rps16, matK and trnL–trnL–trnF and nuclear regions ITS and ETS (p = 0.41 in ILD test) indicated that C. nasuensis was distinct from both C. filipes and C. macroglossa, supporting the recognition of C. nasuensis as an independent species.

Editor's pick

A paper awarded the Best Paper Prize 2023

Volume 72 (2021) Issue 3 Pages 179-204

Biosystematic Studies on Lilium (Liliaceae) I. Phylogenetic Analysis Based on Chloroplast and Nuclear DNA Sequences and a Revised Infrageneric Classification

Seita T. Watanabe, Kazuhiko Hayashi, Katsuro Arakawa, Shizuka Fuse, Hidetoshi Nagamasu, Hiroshi Ikeda, Atsushi Kuyama, Piyakaset Suksathan, Manop Poopath, Rachun Pooma, Yong-Ping Yang, Minoru N. Tamura

Based on molecular phylogenetic evidence, phylogenetic analyses of both cpDNA and nrDNA sequences based on 76 (cp) and 77 (nr) samples representing 64 species, two subspecies, and three (cp) and two (nr) varieties of Lilium and six (cp) and five (nr) samples from Cardiocrinum, Fritillaria, and Notholirion as outgroups were used to better understand relationships within Lilium and to revise its infrageneric classification. The same individuals were used for both cpDNA and nrDNA analyses to avoid confusion caused by genetic polymorphism within a species. Nine thousand eight hundred thirty seven bp from 10 cpDNA regions and 1069 bp from the nuclear (ITS + ETS) regions were analyzed. The same twelve clades were formed in Lilium in both the chloroplast and nuclear trees (one clade of the former tree and one clade of the latter tree were not strictly formed because of low resolution). In light of the cpDNA and nrDNA trees obtained, 13 morphological characters, including a pair of marginal ridges along a central groove on the adaxial surface of the tepals were examined with attention given for the first time to the use of this character as having diagnostic value. The morphological evidence supported the twelve clades. Based on molecular and morphological evidence, a revised infrageneric classification of Lilium recognizing twelve clades as twelve sections is proposed.

Editor's pick

A paper awarded the Best Paper Prize 2022

Volume 72 (2021) Issue 2 Pages 93-111

Functional Traits Divergence in Parallelly Evolved Rheophytic Populations of Solidago virgaurea L. Complex (Asteraceae) in Japan

Shota Sakaguchi, Atsushi Abe, Koki Nagasawa, Daiki Takahashi, Hiroaki Setoguchi, Masayuki Maki, Ryuta Kyan, Takako Nishino, Naoko Ishikawa, Shun K. Hirota, Yoshihisa Suyama, Motomi Ito

Repeated adaptation to similar environments can lead to divergence of phenotypes in different populations. Such evolutionary changes sometimes result in incongruence between morphology and molecular phylogeny, for which careful biological investigation is required. Natural phenotypic variation in rheophytic populations of the Solidago virgaurea L. complex (Asteraceae), which evolved multiple times from ancestral dryland forms in Japan, are here reported. Common garden experiments and population genetic analysis were used to evaluate the extent to which parallelly evolved rheophytes diverged in morphological, phenological and genotypic features to understand their complex evolutionary history. Significant divergence among rheophytic populations was detected in multiple traits, even in leaf morphological traits, which are similarly subjected to purifying selection by water pressure in riparian habitats. Whereas most of the variation were attributed to differences between specific pairs of populations, flowering phenology showed latitudinal variation, which likely evolved along a large-scale environmental cline. Multivariate analysis revealed that at least the population on Okinawa Isl., at the edge of the range of the species, is phenotypically distinguishable from rheophytic populations on the main islands. Phylogenetic analysis also suggested that the Okinawan rheophytes are genetically isolated from parapatric dryland populations. Based on the evidence, the Okinawan rheophytic plants are recognized as specifically distinct and are described as Solidago yambaruensis S. Sakaguchi & Mot. Ito.

Editor's pick

A paper awarded the Best Paper Prize 2022

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2023 Volume 74 Issue 2

Detecting the Initial Stage of Diversification within Plants of Machilus (Lauraceae) in the Bonin Islands Shizuka Tsuneki, Hidetoshi Kato, Noriaki Murakami
Biosystematic Studies of Carex (Cyperaceae) III. Phylogenetic Analyses of the Carex filipes complex (sect. Paniceae) in East Asia, with Reference to Morphology, Karyology and Taxonomy Kotaro T. Takahashi, Jiro Oda, Shizuka Fuse, Okihito Yano, Yi-Fei Lu, Xiao-Feng Jin, Minoru N. Tamura
Quantitative Variability of Flower Color and Outer Morphological Traits in Cypripedium macranthos s. lat. (Orchidaceae) on Rebun Island, Hokkaido, Japan Hideki Takahashi
First Record of Thrixspermum annamense (Orchidaceae) from Iriomote Island, Ryukyu Islands, Japan, with Discussions on its Intraspecific Taxonomy Kenji Suetsugu, Shun K. Hirota, Koji Yonekura, Atsushi Abe, Yoshihisa Suyama, Tian-Chuan Hsu

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