Paspalum distichum

Basic information
Scientific name	Paspalum distichum	Click to magnify
Common names	Knotgrass, Jointgrass, Water couch, Seashore paspalum
Higher taxon	Poaceae, Poales, Liliopsida, Magnoliophyta
Natural range	North America.
Habitat	Natural beach, lake or pond, rice field, sandy place, swamp, waterfront.

Invasion information
Range in Japan	Kanto and Hokuriku District to western Japan
Origin	Unknown.
Date	The first record was in 1924 in Wakayama Pref. Spread since 1945. A variety P. d. var. indutum was at first recorded in 1970 in Fukuoka Pref., and have spread.
Route	Deliberate: for animal feeding stuff Accidental: unknown vector
Impact	Competition with native and crop plants. Host of insects, fungi, and viruses. Native organism(s) affected: Native and crop plants (including rice).
Regulation in Japan	South Korea prohibits import of this species.
Introduced range in other countries	South America, Europe, Oceania, Asia, Africa

Reference	Notes
Jpn Assoc Advanc Phyto-Regul & Inst Contr Agrochem, Minist Agr, China (2000) Chinese Colored Weed Illustrated Book. Zenkoku-Noson-Kyoiku-Kyokai, Tokyo Shimizu (ed) (2003) Naturalized Plants of Japan. Heibonsha, Tokyo (in Jpn)