Acta Phytotaxonomica et Geobotanica

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Volume 74 (2023) Issue 1 Pages 1-15
Hidden Diversity of Ferns: Haplopteris mediosora Have Survived as Independent Gametophytes in Japan
Katsuhiro Yoneoka, Kiyotaka Hori, Toshifumi Kataoka, Tao Fujiwara, Atsushi Ebihara, Noriaki Murakami

Haplopteris mediosora (Hayata) X. C. Zhang (Pteridaceae), a fern with linear simple fronds is widely distributed at high elevations from the Himalayas through China, the Philippines and Taiwan to Japan. In Japan, sporophytes of H. mediosora were recorded only from Azusa-shiraiwa, a mountain of Okuchichibu region, and have not been seen for over 50 years. The hypothesis that such rare species still persist as gametophytes was proven during this study when gametophytes were found on several mountains in the Oku-chichibu region. Phylogenetic analysis of rbcL sequences collected in this study demonstrated that the gametophytes, identified as H. mediosora, and sporophytes of H. mediosora formed a clade and were distinct from related species of Haplopteris. The gametophytes were also growing independently because of the absence of sporophytes. A comparison of the haplotypes of the matK and trnL-F regions showed that the gametophytes had two chloroplast DNA haplotypes. The polymorphisms may have been derived from ancestral sporophytes that were present in Japan during the glacial period. Despite the rarity of sporophytes in the area, the independent gametophytes occur in four distant localities in the Oku-chichibu mountains.
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Editor's pick
A paper awarded the Best Paper Prize 2024
Volume 74 (2023) Issue 2 Pages 71-103
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

Calex filipes (Cyperaceae) and its closely related species, which we tentatively refer to as the C. filipes complex, are greatly diverse morphologically. The closely allied species have often been included within C. filipes where they have been treated by as many as seven infraspecific taxa at the rank of variety. To better determin the taxonomic distinctness of the individual species and infraspecific taxa, we undertook molecular phylogenetic analyses of individuals of the C. filipes complex using the plastid DNA regions atpB–rbcL, rpl16–rpl16–rps3, rps16, matK, and trnL–trnL–trnF and nuclear DNA regions ITS and ETS. We compared the morphology of as many individuals as possible and determined the somatic chromosome number of some individuals to supplement missing information. It was concluded that the C. filipes complex comprises ten species, two varieties and one hybrid, i.e. C. arisanensis, C. curtispica, C. egena, C. filipes var. filipes, C. filipes var. tremula, C. kujuzana, C. ×kurogii, C. kuzakaiensis, C. rouyana var. arakiana, C. rouyana var. rouyana, C. sohayakiensis, C. sparsinux and C. vaniotii. A diagnostic key to separate them, based on morphology, and chromosome numbers are presented. Two new species, C. curtispica and C. sohayakiensis and one new hybrid, C. ×kurogii, are described. The origin of the hybrid isalso discussed.
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Editor's pick
A paper awarded the Best Paper Prize 2024
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.
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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.
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Editor's pick
A paper awarded the Best Paper Prize 2023

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