Pacific Island Ecosystems at Risk (PIER)

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Marsilea quadrifolia
L., Marsileaceae
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Present on Pacific Islands?  no

Primarily a threat at high elevations?  no

Common name(s): [more details]

English: European pepperwort, European waterclover

French: fougere d'eau

Japanese: denjiso

Spanish: aigret, viola

Habit:  aquatic fern

Description:  "Plants forming diffuse colonies.  Rhizome 0.5-1.3 mm thick, reddish brown to black, sparsely hairy to glabrate, bearing short nodal shoots, nodal and internodal roots 0.2-0.3 mm thick, internodes 0.6-5 cm long; rhizome in water 0.9-2.0 mm thick, green, glabrous, aerenchymatous, internodes 4-12 cm long.  Land leaves with terete petioles 5.4-16.5 cm long, 0.5-1.0 mm tick, leaflets 0.7-2.1 cm long, 0.6-1.9 cm wide, symmetrical, flabellate, glabrous or with a few non-overlapping hairs; floating leaves with terete petioles 14-30 cm long, 1.0-1.5 mm thick, leaflets 1.3-3 cm long, 1.2-3.1 cm wide; hydropoten irregularly distributed or absent.  Fertile leaves produced on land (rarely in water) on long shoots or short shoots, bearing 1-3 sporocarps on a branched or unbranched peduncle attached 1-12 mm above petiole base; unbranched peduncle or ultimate branches of peduncle 3-16 mm  long, common trunk of branched peduncle or ultimate branches of peduncle 3-16 mm long, common trunk of branched peduncle 1-4 mm long (rarely 2-3 unbranched peduncles attached separately to the same petiole).  Sporocarps 4.0-5.6 mm long, 3.1-4.0 mm wide, 2.3-2.8 mm thick, rounded, oval, or elliptical in lateral view, elliptical to nearly round in cross section, dark brown to black, hairy but soon glabrate; raphe 1.4-1.9 mm long, inferior tooth usually absent, superior tooth absent or 0.1-0.2 mm long, acute; sporocarp veins ca 20, forking halfway from median vein, the branches anastomosing just before the tips or free.  Sori 10-17 per sporocarp, borne on a sorophore with a free, acute tip, ca 12 microsporangia and 3-7 megasporangia per sorus; microspores ca 43 per sporangium, 56-61 μm in diameter; megaspores 560-610 μm long, 355 μm wide, with an apical papilla 60  long" (Johnson, 1986; pp. 35-39).

Habitat/ecology:  "A major weed of paddy fields and a troublemaker in ponds, lakes and irrigation systems.  It frequents paddy crops and warm, shallow, muddy edges of fresh water ponds" (Holm et al., 1997; pp. 455, 457).

In North America, "found in ponds, river backwaters, and marshes, where it occurs from the shores out to a depth of ca 0.5 m" (Johnson, 1986; pp. 35-39).

Propagation:  Spores and possibly by birds or dispersal by flowing water (Johnson, 1986; pp. 35-39). "Vegetatively by means of creeping rhizomes or following dispersal and establishment of rhizome fragments" (Holm et al., 1997; p. 458).

Native range:  Europe; also cultivated and naturalized elsewhere (GRIN).

Presence:

Pacific
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Philippines
Philippine Islands
Philippine Islands introduced
invasive
Waterhouse, D. F. (1993) (pp. 67, 78)
Pacific Rim
Country/Terr./St. &
Island group
Location Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Australia
Australia (continental)
Queensland   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 455)
Cambodia
Cambodia
Cambodia (Kingdom of) introduced
invasive
Waterhouse, D. F. (1993) (pp. 67, 78)
China
China
China (People's Republic of)   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 455)
Colombia
Colombia
Colombia (Republic of)   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 455)
Indonesia
Indonesia
Indonesia (Republic of) introduced
invasive
Waterhouse, D. F. (1993) (pp. 67, 78)
Japan
Japan
Japan (country)   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 455)
South Korea
South Korea
South Korea (Republic of)   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 455)
Malaysia
Malaysia
Malaysia (country of) introduced
invasive
Waterhouse, D. F. (1993) (pp. 67, 78)
Mexico
Mexico
Mexico (United Mexican States)   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 455)
Taiwan
Taiwan Island
Taiwan Island   Holm, Leroy/Doll, Jerry/Holm, Eric/Pancho, Jaun/Herberger, James (1997) (p. 455)
Thailand
Thailand
Thailand (Kingdom of) introduced
invasive
Waterhouse, D. F. (1993) (pp. 67, 78)
Vietnam
Vietnam
Vietnam (Socialist Republic of) introduced
invasive
Waterhouse, D. F. (1993) (pp. 67, 78)


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This page was created on 30 MAY 2005 and was last updated on 20 MAY 2013.