Lygodium japonicum

(Thunb.) Sw.

Japanese Climbing Fern

Lygodiaceae

Lygodium japonicum is a climbing fern in the family Lygodiaceae. It is widely distributed throughout South to East Asia, and is naturalized elsewhere, including the United States.

Lygodium japonicum

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Description

Lygodium japonicum is a climbing plant that produces extremely long leaves (often several meters long) that grow indeterminately. This appears to be the stem, but is actually the rachis of the leaf. From the sides of the rachis are pinnae that are 2-3 pinnate themselves, roughly triangular in outline, about 6 to 15 cm long and wide. The ultimate segments are lanceolate, often lobed or divided at the base with lobes directed towards the tip. The fertile pinnae are similar to the sterile pinnae described above, but on the ultimate segments they have narrow lobes containing the sporangia (FNAEC 1993).

As the only species of Lygodium in Japan and Korea, this species is unlikely to be confused for other ferns in those areas, but coexists with similar species elsewhere (Hassler 2022). In Florida, it coexists with the similar Lygodium microphyllum, but that species has pinnules that are not divided further, unlike Lygodium japonicum (FNAEC 1993).

Uses

Note: Please see the disclaimer regarding any information about medical or edible uses.

Lygodium japonicum is edible and young leaves are used in stir-fries and soup (Liu et al. 2013). In its native range, it is often used medicinally to treat wounds, but a wide variety of other uses have been reported, such as a diuretic, expectorant, treating kidney stones, and reducing inflammation (EPPO 2019).

Lygodium japonicum has been grown as an ornamental in areas such as the United States, but has escaped and is now a serious weed in some places (FNAEC 1993). It is also used as a growing medium (EPPO 2019).

Distribution

Lygodium japonicum grows among secondary vegetation, and can form dense canopies. In the United States, it prefers wetter soils, but can spread in a variety of habitats (EPPO 2019). It is native to eastern to southern Asia, from Japan to Sri Lanka, west to Java, Indonesia. It is also naturalized in South Africa, eastern Australia (EPPO 2019), and the southeastern United States, from eastern Texas to Florida, north to North Carolina (FNAEC 1993; Wu et al. 2013).

Where it is naturalized, Lygodium japonicum can become a serious weed, often forming dense cover that smothers native plants. Due to its climbing nature, it can also spread fires to the canopy, with ecological and economic impacts (due to reduced timber yield) (EPPO 2019).

Status

References

EPPO (European and Mediterranean Plant Protection Organization). 2019. Lygodium japonicum (Thunb.) Sw. EPPO Bulletin 49: 261–266. Hassler, M. 2022. World Ferns. Synonymic Checklist and Distribution of Ferns and Lycophytes of the World. Version 13.2; last update 2022 July 2. [accessed 2022 Jul 12]. <a>www.worldplants.de/ferns/</a> FNAEC (Flora of North America Editorial Committee), editor. 1993. Flora of North America, north of Mexico. Volume 2: Pteridophytes and Gymnosperms. New York: Oxford University Press. Liu, Y., Wujisguleng, W., and Long, C. 2012. Food uses of ferns in China: a review. Acta Societatis Botanicorum Poloniae 81: 263–270. Wu, Z. Y., Raven, P. H., and Hong, D. Y., eds. 2013. Flora of China. Vol. 2-3 (Lycopodiaceae through Polypodiaceae). Beijing: Science Press, and St. Louis: Missouri Botanical Garden Press.

Description

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