• Korean Journal of Plant Taxonomy
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• v.46 no.2
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• pp.149-162
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• 2016

Five species of the genus Leontopodium are recognized in Korea, but their taxonomic positions have been controversial. To clarify the taxonomic entity of these Korean species, we examined their morphological characters based on herbarium specimens and field observations. Valuable distinguishing characters for identification included the plant height, the basal shape of cauline leaves, the type and position of inflorescence, the types of hairs, the presence of leaves at the anthesis, and hairs on the phyllaries. Based on our observations, we were able to determine the taxonomic relationships between L. japonicum and its relatives, L. coreanum and L. hallaisanense. We also included the morphological characters of L. seorakensis in continuous variations of L. leiolepis, which we treated as synonyms. Consequently, we classified these Korean Leontopodium species into four taxa - L. coreanum var. coreanum, L. coreanum var. hallaisanense, L. leiolepis, and L. leontopodioides - with appropriate descriptions and illustrations.

• ALGAE
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• v.35 no.3
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• pp.213-224
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• 2020

The freshwater red algal genus Sheathia contains species with heterocortication (both bulbous and cylindrical cells covering the main axis) and homocortication (only cylindrical cells). When the genus was proposed, the species with heterocortication were revised, but all specimens with homocortication were assigned to Sheathia arcuata with the caveat that it may represent a species complex. Recent studies have described new species with homocortication and S. arcuata has been rendered paraphyletic. In the current study, new sequences of the rbcL and 5′ region of the cytochrome c oxidase subunit I markers were combined with previously published data to construct a robust phylogeny and circumscribe new species. Four new species, S. abscondita, S. californica, S. plantuloides, and S. transpacifica are proposed. Examination of morphological characters among homocorticate species show no diagnostic characters to distinguish among species, whereas S. plantuloides is only known from sporophytes (chantransia) so it lacks the typical morphological characters derived from the gametophytes for comparison. Although DNA sequence data would be needed to make a positive species identification, geography could be employed to narrow the identification to one or two species. The genus is geographically widespread having been recorded from oceanic islands and five continents, whereas the individual species typically occur on a single continent. With this study, the number of species recognized in Sheathia is raised to 17; seven heterocorticate and 10 homocorticate, making this genus one of the most species rich in the Batrachospermales. As well, the resulting phylogeny provides insights into the evolution of heterocortication in Sheathia.

• Korean Journal of Plant Taxonomy
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• v.45 no.3
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• pp.227-238
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• 2015

Korean species within the genus Astragalus have been taxonomically revised based on herbarium specimens and field examinations. In this study, we recognized the following eight species and one variety: A. laxmannii subsp. laxmannii, A. dahuricus, A. sikokianus, A. uliginosus, A. schelichowii, A. setsureianus, A. mongholicus var. dahuricus, A. mongholicus var. nakaianus, and A. sinicus. Based on recent taxonomic progress with this genus, their scientific names are being reconsidered. A Korean plant, previously recorded as A. adsurgens, is included in the polymorphic taxa A. laxmannii subsp. laxmannii. Astragalus koraiensis was initially described from Gangwon Province as an endemic species, and it is now regarded as conspecific with A. sikokianus. Furthermore, the taxonomic entities and their morphological characteristics have been clarified for A. schelichowii and A. setsureianus, both of which are not well known in Korea. We provide a key to these species and enumerate their synonymies and taxonomic notes.

• Applied Microscopy
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• v.42 no.2
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• pp.111-114
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• 2012

The scanning electron microscopy is an ideal technique for examining plant surface at high resolution. Most hydrate samples, however, must be fix and dehydrate for observation in the scanning electron microscope. Because the microscopes operate under high vacuum, most specimens, especially biological samples, cannot withstand water removal by the vacuum system without morphological distortion. Cryo-techniques can observe in their original morphology and structure without various artifacts from conventional sample preparation. Rapid cooling is the method of choice for preparing plant samples for scanning electron microscopy in a defined physiological state. As one of cryo-technique, high-pressure freezing allows for fixation of native non-pretreated samples up to $200{\mu}M$ thick and 2 mm wide with minimal or no ice crystal damage for the freezing procedure. In this study, we could design to optimize structural preservation and imaging by comparing cryo-SEM and convention SEM preparation, and observe a fine, well preserved Arabidopsis stem's inner ultrastructure using HPF and cryo-SEM. These results would suggest a useful method of cryo-preparation and cryo-SEM for plant tissues, especially intratubule and vacuole rich structure.

• Korean Journal of Plant Resources
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• v.22 no.5
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• pp.412-424
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• 2009

The flora and vegetation of Chuncheon area were investigated from March, 2006 to September, 2008. Vascular plants of investigated regions were composed of 118 families, 496 genera, 894 species, 2 subspecies, 132 varieties, and 38 forms, totally 1,066 taxa, and the Pteridophyta index (Pte-Q) was 1.17. Forty two taxa including endemic genus Hanabusaya and Echinosophora among the 1,066 taxa were Korean endemic. Thirty three rare and endangered plants and 119 specially designated plants by Ministry of Environment were also investigated. The naturalized plants were 71 taxa, and percent of naturalized plant species were 6.66%. The vegetation of Chuncheon area were classified into five communities such as Quercus mongolica community, Pinus densiflora-Quercus mongolica community, Quercus mongolica-Acer mono community, Quercus mongolica-Quercus variabilis community and Quercus mongolica-Betula davurica community.

• Korean Journal of Plant Resources
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• v.28 no.4
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• pp.487-510
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• 2015

This study was carried out to inventory the vascular plant flora in Deokjeokdo and its adjacent regions (Mungapdo, Soyado), Ongjin-gun, South Korea, from April to October 2014. Based on the voucher specimens, vascular plants in this area consisted of 108 families, 362 genera, 578 species, 5 subspecies, 66 varieties and 4 forms, totally 653 taxa. In the flora of this area, 5 taxa of Korean endemic plants were found distributed in the sites, including Hepatica insularis Nakai and Asarum glabrata (C.S.Yook & J.G.Kim) B.U.Oh. Korean rare and endangered plants found in this area were 1 taxa of Critical Endangered Species (CR) and 5 taxa of Vulnerable Species (VU). The floristic regional indicator plants found in this area were 67 taxa comprising 3 taxa of grade V, 2 taxa of grade IV, 12 taxa of grade III, 3 taxa of grade II and 47 taxa of grade I. Naturalized plants consisted of 67 taxa, such as Chenopodium album L. and Erigeron annuus (L.) Pers. were recognized widely distributed in the area.

• Korean Journal of Materials Research
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• v.29 no.6
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• pp.349-355
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• 2019

This study deals with the microstructure and tensile properties of 600 MPa-grade seismic reinforced steel bars fabricated by a pilot plant. The steel bar specimens are composed of a fully ferrite-pearlite structure because they were air-cooled after hot-rolling. The volume fraction and interlamellar spacing of the pearlite and the ferrite grain size decrease from the center region to the surface region because the surface region is more rapidly cooled than the center region. The A steel bar specimenwith a relatively high carbon content generally has a higher pearlite volume fraction and interlamellar spacing of pearlite and a finer ferrite grain size because increasing the carbon content promotes the formation of pearlite. As a result, the A steel bar specimen has a higher hardness than the B steel bar in all the regions. The hardness shows a tendency to decrease from the center region to the surface region due to the decreased pearlite volume fraction. On the other hand, the tensile-to-yield strength ratio and the tensile strength of the A steel bar specimen are higher than those of the B steel bar with a relatively low carbon content because a higher pearlite volume fraction enhances work hardening. In addition, the B steel bar specimen has higher uniform and total elongations because a lower pearlite volume fraction facilitates plastic deformation caused by dislocation slip.

• Korean Journal of Plant Resources
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• v.35 no.1
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• pp.109-133
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• 2022

We investigated the flora of Gwanmae island and discussed important vascular plants found on the island. We made plant list using voucher specimens collected from Gwanmae island from 2016 to 2021 and deposited in CNU. There are 500 taxa in Gwanmae island, comprising 103 families, 307 genera, 461 species, 4 subspecies, 32 varieties and 3 forms. Eight endemic plants of Korea were found including Saussurea polylepis Nakai. There are 15 red list plants designated by Ministry of Environment including Cleisostoma scolopendrifolium (Makino) Garay and Woodwardia japonica (L. f.) Sm. There are total 126 taxa of floristic regional indicator plants including 4 taxa of level V such as Juniperus procumbens (Siebold ex Endl.) Miq., 4 taxa of level IV such as Wisteria japonica Siebold & Zucc., 45 taxa of level III such as Rubus trifidus Thunb., 16 taxa of level II such as Glehnia littoralis F. Schmidt and 56 taxa of level I such as Carpesium glossophyllum Maxim. There are 32 invasive plants including Cerastium glomeratum Thuill.

• Journal of Ecology and Environment
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• v.46 no.4
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• pp.292-303
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• 2022

Background: Climate change significantly influences the geographical distribution of plant species worldwide. Selecting indicator species allows for better-informed and more effective ecosystem management in response to climate change. The Korean Peninsula is the northernmost distribution zone of warm temperate evergreen broad-leaved (WTEB) species in Northeast Asia. Considering the ecological value of these species, we evaluated the current distribution range and future suitable habitat for 13 WTEB tree species designated as climate-sensitive biological indicator species. Results: Up-to-date and accurate WTEB species distribution maps were constructed using herbarium specimens and citizen science data from the Korea Biodiversity Observation Network. Current northern limits for several species have shifted to higher latitudes compared to previous records. For example, the northern latitude limit for Stauntonia hexaphylla is higher (37° 02' N, Deokjeokdo archipelago) than that reported previously (36° 13' N). The minimum temperature of the coldest month (Bio6) is the major factor influencing species distribution. Under future climate change scenarios, suitable habitats are predicted to expand toward higher latitudes inland and along the western coastal areas. Conclusions: Our results support the suitability of WTEB trees as significant biological indicators of species' responses to warming. The findings also suggest the need for consistent monitoring of species distribution shifts. This study provides an important baseline dataset for future monitoring and management of indicator species' responses to changing climate conditions in South Korea.

• Korean Journal of Plant Resources
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• v.32 no.1
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• pp.72-85
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• 2019

This study was conducted to investigate the vascular flora distributed in the Gatbawi District of Palgongsan Natural Park and to provide basic data for the conservation and management of the natural resources. The results of the investigation of the flora with the Gatbawi District from April 2015 through October 2017 are as follows. As a result of drawing up a list of flora based on the specimens of evidence, as for the entire flora, 238 taxa were identified in total: 75 families, 167 genera, 214 species, 3 subspecies, 18 variants and 3 varieties. Also, one species of rare plant, 20 particular floristic species and a total of 18 species of naturalized plant were found.