L., Marsileaceae |
Present on Pacific Islands? no
Primarily a threat at high elevations? no
Common name(s): [more details]
English: clover fern, dwarf waterclover, pepperwort, small water clover, water clover |
Habit: aquatic fern
Description: "Plants forming extensive but diffuse colonies. Rhizome 0.4-0.8 mm thick, green to light brown, densely covered with tan hairs at apices but glabrate proximally, sometimes
bearing short branches with numerous leaves at nodes, nodal and internodal roots
0.1-0.3 mm thick, internodes 1-3.5 cm long; rhizome in water 0.5-0.8 mm tick,
green to brown, glabrous, internodes 4-11 cm long. Land leaves with
erect terete petioles 5-13 cm long, 0.4-0.8 mm thick, leaflets 1.2-2 cm long,
0.8-1.7 cm wide, cuneate to flabellate, glabrous to sparsely hairy, with
concave, straight, or convex lateral margins and entire to crenulate terminal
margins; leaves in water often with leaflets emergent rather than floating, with
stiff terete petioles 13.5-47 cm long, 0.3-0.8 mm thick, leaflets 1.7-1.8 cm
long, 1.5-1.6 cm wide; hydropoten infrequent. Fertile leaves produced on
land, bearing 1-4 sporocarps per leaf, on either branched or unbranched
peduncles attached at or slightly above the base of the petiole, unbranched
peduncles and ultimate divisions of branching peduncles 2.6-6.0 mm long, the
common trunk of branched peduncles 0.4 mm long. Sporocarps 2.6-4.1
mm long, 2.4-3.1 mm wide, 1.3-1.7 mm thick, nearly round to slightly oblong in
lateral view, ovate or elliptical in cross section, brown to black, hairy to
glabrate; raphe 1.5-2.2 mm long, inferior tooth 0.3-0.6 mm long, obtuse or
truncate, or absent, superior tooth 0.3-0.6 mm long, acute; sporocarp veins ca
15, forking midway, branches often anastomosing at tips. Sori 9-12
per sporocarp, attached to a sorophore with a free acute tip, 9-14
microsporangia and 2-7 megasporangia per sorus. Microspores 50-64 per
sporangium, 50-75 μm in diameter, with 1-2 spores
per sporangium occasionally brown, misshapen, up to 32 μm long. Megaspores
400-525 μm long, 355-380 μm wide, with an apical lpapilla 40-65 μm long"
(Johnson, 1986; pp. 39-40).
Habitat/ecology: Low elevations near the coast in fresh water or occasionally in brackish water on sandy or clay substrates. In northeastern Brazil the plants have been collected in seasonal ponds (Johnson, 1986; pp. 39-40).
Propagation: Spores or rhizomes (Waterhouse, 1994; p. 114).
Native range: Africa and India. It is found in Trinidad, Tobago and northeastern Brazil, but these may be recent introductions (Johnson, 1986; pp. 39-40).
Presence:
Control: Biological: Waterhouse (1994, pp. 115-116) lists natural enemies of
the species.
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
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
Cambodia
Cambodia
Cambodia (Kingdom of)
Waterhouse, D. F. (1993) (pp. 67, 78)
Indonesia
Indonesia
Indonesia (Republic of)
Waterhouse, D. F. (1993) (pp. 67, 78)
Malaysia
Malaysia
Malaysia (country of)
native
U.S. Dept. Agr., Agr. Res. Serv. (2013)
Thailand
Thailand
Thailand (Kingdom of)
Waterhouse, D. F. (1993) (pp. 67, 78)
Vietnam
Vietnam
Vietnam (Socialist Republic of)
Waterhouse, D. F. (1993) (pp. 67, 78)
Indian Ocean
Country/Terr./St. &
Island group
Location
Cited status &
Cited as invasive &
Cited as cultivated &
Cited as aboriginal introduction?
Reference &
Comments
Comoros
Comoro Islands
Comoro Islands
native
U.S. Dept. Agr., Agr. Res. Serv. (2013)