著者
Hiroshi Takahashi Tomohisa Yukawa Masayuki Maki
出版者
The Japanese Society for Plant Systematics
雑誌
Acta Phytotaxonomica et Geobotanica (ISSN:13467565)
巻号頁・発行日
vol.72, no.3, pp.265-274, 2021-10-31 (Released:2021-11-27)

Petrosavia amamiensis (Petrosaviaceae) is described as a new species from Amami-Oshima Island, Kagoshima Prefecture, Japan. The plants were previously identified as P. sakuraii. The flowers of P. amamiensis are autonomously self-pollinated at the beginning of anthesis, while those of P. sakuraii are self-pollinating at a later stage of anthesis. Petrosavia amamiensis has a shorter aerial stem, shorter internodes, more densely flowered inflorescence and smaller seeds than P. sakuraii. Moreover plastid and nuclear DNA differ greatly between P. amamiensis and P. sakuraii.
著者
Takehiko Kobori Masayuki Maki Yasushi Fujiyoshi Masato Iguchi Seiji Fukushima
出版者
公益社団法人 日本気象学会
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
pp.2022-037, (Released:2022-09-09)

We developed a method for estimating the height and growth rate of volcanic eruption columns, at high-temporal resolution, by processing vertical cross-sectional images of areas around the crater obtained with a marine radar tilted on its side. We applied our method to 127 eruptions occurring at Sakurajima (Kagoshima, Japan) from June to December 2019 and successfully estimated the time-series height of the eruption column and its growth rate every 2.5 seconds. In 48 cases, we obtained the maximum height of the eruption column and confirmed that these results were consistent with those estimated using meteorological radar. Although the maximum height estimated with our method tended to be lower than that observed by monitoring cameras, results could be obtained even when observations were difficult due to cloud effects, etc.
著者
Takehiko Kobori Masayuki Maki Yasushi Fujiyoshi Masato Iguchi Seiji Fukushima
出版者
公益社団法人 日本気象学会
雑誌
SOLA (ISSN:13496476)
巻号頁・発行日
vol.18, pp.231-235, 2022 (Released:2022-10-28)
参考文献数
13

We developed a method for estimating the height and growth rate of volcanic eruption columns, at high-temporal resolution, by processing vertical cross-sectional images of areas around the crater obtained with a marine radar tilted on its side. We applied our method to 127 eruptions occurring at Sakurajima (Kagoshima, Japan) from June to December 2019 and successfully estimated the time-series height of the eruption column and its growth rate every 2.5 seconds. In 48 cases, we obtained the maximum height of the eruption column and confirmed that these results were consistent with those estimated using meteorological radar. Although the maximum height estimated with our method tended to be lower than that observed by monitoring cameras, results could be obtained even when observations were difficult due to cloud effects, etc.
著者
Shinji Fujii Tadashi Yamashiro Sachiko Horie Masayuki Maki
出版者
The Japanese Society for Plant Systematics
雑誌
Acta Phytotaxonomica et Geobotanica (ISSN:13467565)
巻号頁・発行日
vol.70, no.2, pp.119-127, 2019-06-30 (Released:2019-07-10)

Recently, we found two species of Crassula newly introduced into central Japan. Based on their morphology, we identified them as Crassula peduncularis and C. saginoides, native to the New World. They closely resemble C. aquatica, which is indigenous to Japan. Here, we describe the morphological distinctions among the three species in detail. In addition, we examined genetic differences among the three species based on sequence variations in the nuclear ribosomal ITS region and three chloroplast intergenic regions. Although C. saginoides was considered to be an inland form of C. aquatica and had been treated as a synonym of C. aquatica, the degree of genetic differentiation was relatively large, suggesting that these two taxa should be considered to be independent species.
著者
Shinji Fujii Yoshinori Tokuoka Masayuki Maki
出版者
The Japanese Society for Plant Systematics
雑誌
Acta Phytotaxonomica et Geobotanica (ISSN:13467565)
巻号頁・発行日
vol.71, no.3, pp.231-242, 2020-10-31 (Released:2020-11-29)

Saxifraga fortunei sensu lato (Saxifragaceae) varies greatly in morphology and includes many infraspecific taxa. As many as five varieties have been recognized in western Japan, although their discrimination based on leaf size or leaf shape, such as cuneate base or degree of lobing is often difficult to determine due to continuous variation. To quantify the variation in leaf morphology, especially focusing on cuneate and parted leaves, 259 samples from 87 populations in western Japan were subject to principal component analysis. Additionally, developmental changes in plants from three selected populations were examined. The findings revealed that plants with parted leaved (var. suwoensis) were discriminated from plants with cuneate and normal leaves, while plants with cuneate leaves (var. obtusocuneata) were within the range of variation of var. fortunei. Leaf shape changes from cuneate to truncate or cordate during the transition from a vegetative state to the flowering state. Cuneate forms usually occurred in sterile plants, but also on flowering plants even within a population. This characteristic was less useful for recognizing var. obtusocuneata. Populations with parted (long lobed) leaves as well as those with cuneate leaves usually grow along streams, confirming that phenotypes are the result of adaptive differentiation toward becoming facultative rheophytes, as previously suggested.
著者
TADASHI YAMASHIRO ASUKA YAMASHIRO MAKOTO OGAWA NOBUHIRA KUROSAKI TOMIKI KOBAYASHI MASAYUKI MAKI
出版者
The Japanese Society for Plant Systematics
雑誌
Acta Phytotaxonomica et Geobotanica (ISSN:13467565)
巻号頁・発行日
vol.63, no.1, pp.29-40, 2012-10-31 (Released:2017-03-21)
参考文献数
36

We examined morphological differentiation and allozyme diversity in nine populations of Vincetoxicum katoi and its close relative V. yamanakae. Although, V. yamanakae has been distinguished from V. katoi in having a larger corolla and gynostegium, the principal component analysis based on 12 floral and three leaf characters did not support the distinction of the two taxa. The six allozyme loci examined revealed that population of V. katoi and V. yamanakae maintained high genetic diversity (P=72.1, A=2.40, h=0.313). The nine populations were clustered into three regions (Kanto-Tokai; middle Kiniki; and Kii-Shikoku) based on genetic differences, contradicting the current taxonomic treatment. Considering the evidence, it is appropriate to treat V. yamanakae as a synonym of V. katoi. The high genetic differentiation among regions suggested that disjunct distribution of the V. katoi-V. yamanakae complex might reflect the persistence of refugia since the last glacial period. In particular, the middle Kinki (Hyogo) population is located outside of known evergreen forest refugia, suggesting that it might have survived during the glacial period within cooler vegetative zones, such as in temperate forests, whereas the populations on the Pacific-side retreated to warm-temperature coastal refugia.