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)
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)
South America (Pacific rim)
South America (Pacific rim)
Colombia (Republic of)   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)


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