Phyllospadix japonicus

{{Short description|Species of aquatic plant}} {{Speciesbox | status = EN | status_system = IUCN3.1 | status_ref = {{cite iucn |author=Short, F.T. |author2=Waycott, M. |year=2010 |title=Phyllospadix japonicus |volume=2010 |page=e.T173341A6994909 |doi=10.2305/IUCN.UK.2010-3.RLTS.T173341A6994909.en |access-date=24 April 2022}} | genus = Phyllospadix | species = japonicus | authority = Makino, 1897 }}

Phyllospadix japonicus, known as Asian surfgrass,{{Cite book|url=http://www.forest.go.kr/kna/special/download/English_Names_for_Korean_Native_Plants.pdf|title=English Names for Korean Native Plants|publisher=Korea National Arboretum|year=2015|isbn=978-89-97450-98-5|location=Pocheon|pages=571|access-date=4 January 2017|via=Korea Forest Service|url-status=dead|archiveurl=https://web.archive.org/web/20170525105020/http://www.forest.go.kr/kna/special/download/English_Names_for_Korean_Native_Plants.pdf|archivedate=25 May 2017}} is a plant species found along the seacoasts of Japan, Korea, and China (Hebei, Liaoning, Shandong). It grows in the intertidal zone along the shore.Makino, Tomitarô. 1897. Botanical Magazine (Tokyo) 11: 137.

Phyllospadix japonicus is a perennial herb that spreads by means of rhizomes. Its leaves are long, reaching up to 100 cm, though they are rarely more than 2.5 mm wide.{{Cite web|url=http://www.efloras.org/florataxon.aspx?flora_id=2&taxon_id=242337520|title=Phyllospadix iwatensis in Flora of China @ efloras.org|website=www.efloras.org|access-date=2017-02-02}}Ohwi, J. (1984). Flora of Japan (in English): 1-1067. Smithsonian Institution, Washington, D.C.Czerepanov, S.K. (1995). Vascular Plants of Russia and Adjacent States (The Former USSR): 1-516. Cambridge University Press.Kharkevich, S.S. (ed.) (1987). Plantae Vasculares Orientalis Extremi Sovietici 2: 1-448. Nauka, Leningrad.Lee, W.T. (1996). Lineamenta Florae Koreae: 1-1688. Seoul: Ak'ademi Sojok.Kuo, J. & de Hertog, C. (2001). Seagrass taxonomy and identification key. Global Seagrass Research Methods: 31-78. Elsevier Science B.V., Amsterdam.