Sedum formosanum subsp. miyakojimense (Crassulaceae), a new subspecies from Miyako-jima Island of the Ryukyu Islands, Japan.

Takuro Ito,Chih-Chieh Yu,Goro Kokubugata,Masatsugu Yokota

doi:10.3897/phytokeys.148.48957

Takuro Ito, Chih-Chieh Yu + Show 2 more

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https://doi.org/10.3897/phytokeys.148.48957

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Abstract

We re-examined the taxonomic status of plants treated as Sedum formosanum (Crassulaceae) from Miyako-jima Island of the Ryukyu Islands, Japan, using morphological comparison and molecular phylogenetic analyses with related species. In morphology, plants from Miyako-jima Island bore a close resemblance to the other plants of S. formosanum, but differed in being perennial, polycarpic, and having lateral axillary branches. Molecular analyses based on ITS of nrDNA and six regions of cpDNA sequencing indicated that the Miyako-jima plants formed a distinct subclade. This subclade was part of a polytomy with three other subclades comprising nine taxa endemic to Taiwan and S. formosanum from other areas, including the type locality. Therefore, we propose and describe the Miyako-jima plants as a new subspecies, Sedum formosanum subsp. miyakojimense.

Highlights

The genus Sedum L. (Crassulaceae) comprises about 470 succulent herbaceous species (Thiede and Eggli 2007)
To clarify the phylogenetic position of S. formosanum growing on Miyako-jima Island, we utilized ITS (Internal Transcribed Spacer region of nuclear ribosomal DNA) sequences of 50 taxa (72 accessions) of Sedum in Asia including S. formosanum from 20 localities in Kyushu, the Ryukyus, Taiwan and the Philippines as ingroup reported by previous study (Mayuzumi and Ohba 2004; Ito et al 2014, 2017a, 2017b) (Tables 1, 2)
We obtained a matrix of 629 base pairs and selected GTR+I+G for the Bayesian analysis

Summary

Introduction

The genus Sedum L. (Crassulaceae) comprises about 470 succulent herbaceous species (Thiede and Eggli 2007). Sedum plants distributed on the Danjo Islands, Japan, which had historically been treated as S. formosanum, were recently described as a distinct taxon, S. danjoense Takuro Ito, H. Based on previous field surveys, we noted that plants treated as S. formosanum on Miyako-jima of the Ryukyus differed morphologically from other populations.

Results

Conclusion