Acta Phytotaxonomica et Geobotanica

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Volume 76 (2025) Issue 1 Pages 21-49
Biosystematic Studies of Carex (Cyperaceae) IV. Phylogenetic Analysis and Infrageneric Classification of the Basal Lineages of C. subg. Carex
Kotaro T. Takahashi, Shizuka Fuse, Hiroshi Noda, Okihito Yano, Hiroshi Ikeda, Sawita Yooprasert, Manop Poopath, Keshab Raj Rajbhandari, Yong-Ping Yang, Minoru N. Tamura

Carex (Cyperaceae) is a diverse genus with approximately 2,150 species. Recent molecular studies showed that, although the genus has a nearly cosmopolitan distribution, East and Southeast Asia is the cradle of its diversiﬁcation. They further showed that Carex comprises six subgenera, among which subg. Carex is the largest in number of species. Despite these studies, the relationships and classification of basal lineages within subg. Carex remain unresolved, owing to their considerable morphological diversity and limited sampling of Asian plants in previous molecular studies. This report is based on a comprehensive phylogenetic analysis of the basal lineages within subg. Carex that used extensive chloroplast CDS data (70 loci, 58,601 bp) obtained from samples collected in Japan, China, Thailand, and the Himalaya. Based on the phylogenetic results as well as an examination of eleven morphological characters, seven sections, Albae, Decorae, Dissitiflorae (a new section for C. dissitiflora and C. bostrychostigma), Filicinae, Graciles, Indicae and Mundae are recognized as basal monophyletic lineages in subg. Carex. In the phylogeny of subg. Carex, Dissitiflorae occupied the most basal position with 100% bootstrap support. A clade (100%) comprising Albae-Graciles subclade (100%) and Indicae-Mundae subclade (100%) diverged as the next branch, followed by the Decorae-Filicinae clade (100%) and the Core subg. Carex clade (84%).
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Editor's pick
A paper awarded the Best Paper Prize 2026
Volume 76 (2025) Issue 3 Pages 169-188
Lepisorus tajimaensis sp. nov. (Polypodiaceae), a New Allohexaploid Species in the Lepisorus thunbergianus Polyploid Species Complex
Tao Fujiwara, Michiyuki Maruoka, Taketoshi Oka, Katsuhiro Yoneoka, Eri Ogiso-Tanaka, Atsushi Ebihara, Noriaki Murakami, Yasuyuki Watano

Based on cytological analyses, phylogenetic analyses using chloroplast and nuclear genes, and morphological examination, Lepisorus tajimaensis T. Fujiw. (Polypodiaceae, Polypodiales) is described as a new allohexaploid species in the Japanese L. thunbergianus polyploid species complex. Our phylogenetic analyses demonstrated that L. tajimaensis originated through interspecific hybridization between L. nigripes and L. oligolepidus. The new species can be distinguished from L. nigripes by the broadly lanceolate rhizome scales (vs. narrowly lanceolate to lanceolate), lanceolate laminae (vs. linear to narrowly lanceolate), scales throughout the abaxial surface of the laminae (vs. scales mainly along costa on the proximal part of the abaxial surface of laminae), and larger sori (3–5 mm in diam.) (vs. 1–2.5 mm in diam.), and from L. oligolepidus by the brown rhizome scales with 3 or 4 rows of marginal transparentlumina (vs. dark brown rhizome scales with 1 or 2 rows of transparent marginal lumina), the light brown leaf scales (vs. dark brown), and sori being closer to the margin (vs. sori nearer costa). Additionally, sterile pentaploid hybrids resulting from backcrossing between L. tajimaensis and one of the parental species, L. nigripes is reported.
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Editor's pick
A paper awarded the Best Paper Prize 2026
Volume 75 (2024) Issue 2 Pages 51-69
Biosystematic Studies on Commelinaceae (Commelinales) II. Phylogeny and Floral Evolution in Murdannia
Chung-Kun Lee, Shizuka Fuse, Manop Poopath, Rachun Pooma, Shuichiro Tagane, Yong-Ping Yang, Hiroshi Tobe, Minoru N. Tamura

Murdannia (Commelinaceae), consisting of some 60 species, is unusual in the family in having both actinomorphic and zygomorphic flowers usually with the median petal on adaxial side, and having either two or three antisepalous stamens. To understand floral evolution in the genus in light of a phylogenetic context, we conducted phylogenetic analyses of 18 species and one cultivar mainly from Asia using plastid DNA sequences, then examined their respective floral morphology. The results showed a monophyly of all 16 Asian species of Murdannia and one cultivar, and of the ten species with zygomorphic flowers. Comparisons with flowers of related genera suggest that great morphological changes occurred early in the evolution of Murdannia, including rotation of a symmetrical plane by 60 degrees so that the median petal of the flowers is positioned at the top on the adaxial side. Within the genus, a change in floral symmetry from actinomorphy to zygomorphy occurred one time and was accompanied by androecial zygomorphy resulting from replacement of one of three antisepalous stamens by a staminode. Additionally, the two latero-abaxial petals usually spread laterally around 160–180 degrees. The infrageneric classification of the Asian species is also briefly discussed.
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Editor's pick
A paper awarded the Best Paper Prize 2025
Volume 75 (2024) Issue 2 Pages 97-111
Biosystematic Studies on the Genus Polygonatum (Asparagaceae) VI. Polygonatum ×hizenense and P. ×sefuriense, Two New Hybrids from Japan
Riko Masuda, Hiroshi Noda, Kazunori Shintaku, Nam Sook Lee, Shizuka Fuse, Minoru N. Tamura

Based on morphology as well as on karyotype and MIG-seq analyses, two new hybrids, Polygonatum ×hizenense and P. ×sefuriense, from Mt. Sefuri, Pref. Saga, Japan, are described. Polygonatum ×hizenense has 26–29% pollen stainability and 2n = 20, is morphologically intermediate between P. falcatum (with 78–98% pollen stainability and 2n = 18) and P. macranthum (with 95–100% pollen stainability and 2n = 22), which occur parapatrically on Mt. Sefuri. A Neighbor Net network based on MIG-seq data showed P. ×hizenense to be positioned between the P. falcatum cluster and the P. inflatum-P. macranthum cluster, also indicating it to be of hybrid origin between P. falcatum and P. macranthum. Likewise, P. ×sefuriense has 29–37% pollen stainability and 2n = 19, morphology intermediate between P. amabile (with 74–92% pollen stainability and 2n = 20) and P. falcatum, which also occur parapatrically on Mt. Sefuri. The MIG-seq analysis showed P. ×sefuriense to be positioned between the P. falcatum cluster and the P. amabile-P. lasianthum var. lasianthum cluster in the obtained network, indicating it to be of hybrid between P. amabile and P. falcatum. In addition, our analysis based on MIG-seq suggested that P. lasianthum var. coreanum should be separated from var. lasianthum as a distinct species, P. taquetii.
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Editor's pick
A paper awarded the Best Paper Prize 2025

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