New records of two alien plants, Juncus torreyi (Juncaceae) and Egeria densa (Hydrocharitaceae) in Korea

Naturalized populations of two alien plants were newly found, and we describe their morphological characteristics and habitats with photographs. One is a member of Juncaceae, Juncus torreyi Coville, and was newly found at a pool of a beach in Gangwon-do. This rush is native to North America and belo...

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Published inSigmul bunryu hag-hoeji = Korean journal of plant taxonomy Vol. 53; no. 1; pp. 54 - 59
Main Authors Jongduk Jung, Hye Ryun Na, Kyu Song Lee, Yeongmin Choi, Woongrae Cho, Jin-oh Hyun
Format Journal Article
LanguageKorean
Published 한국식물분류학회 2023
Subjects
Alien plants
Egeria densa
Hydrocharitaceae
Juncaceae
Juncus torreyi
new record
Hydrocharitaceae
Juncus torreyi
new record
Juncaceae
Alien plants
Egeria densa
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ISSN1225-8318

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Summary:Naturalized populations of two alien plants were newly found, and we describe their morphological characteristics and habitats with photographs. One is a member of Juncaceae, Juncus torreyi Coville, and was newly found at a pool of a beach in Gangwon-do. This rush is native to North America and belongs to the sect. Ozophyllum (subgen. Juncus) according to certain morphological characteristics, such as its racemose inflorescence, the absence of floral bracteole, and unitubular leaves with perfect septa. J. torreyi is easily distinguishable from Korean rushes by its long rhizomes with swollen nodes and globular head with 25-100 flowers. Its introduction into Japan and Europe was reported, but the ecological risk associated with its over-dispersal is not known. The other alien plant is a submerged plant, Egeria densa Planch. (Hydrocharitaceae), which was found in streams in Gyeongsangbuk-do and ditches in the Busan-si area, both of which being in the watershed of the Nakdong River. Egeria densa is similar to Hydrilla verticillata (L.f.) Royle, which is native to Korea. However, it is distinguished from H. verticillata by its larger flowers and lack of overwintering organs. This alien plant is native to South America and was introduced for aquarium gardening and naturalized around the world. Egeria densa is treated as a malignant weed due to its asexual reproduction and rapid growth. Size changes and the number of populations of E. densa must be investigated.
Bibliography:The Plant Taxonomic Society of Korea
KISTI1.1003/JNL.JAKO202316543272114
ISSN:1225-8318