Monochoria vaginalis (N.L.Burm.) K.Presl, Pontederiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Pontederia vaginalis Burm. f.

Common name(s): [more details]

Bikol: upi-upi

Bontoc: saksaklung

Cebuano: gabi-gabi

Chinese: ya she cao

English: cordate monochoria, heartshape false pickerelweed, monochoria, oval-leaf monochoria, oval-leaf pondweed, pickerel weed

Fijian: mbekambekairanga

Filipino: gabing-uak, kalaboa

Iloko: lapa-lapa

Japanese: kōnagi

Tagalog: biga-bigaan

Habit:  aquatic herb

Description: 

Genus: Glabrous palustrine herbs, with obliquely erect stems arising from a suberect or creeping rhizome, the leaves radical, long-petiolate; inflorescence racemiform or subumbelliform, the flowers deflexed after anthesis, the 3 inner tepals the broader; 5 stamens with small, yellow anthers, the sixth with a longer filament with a lateral tooth and a larger, blue anther; fruit a loculicidally dehiscent capsule." (Smith, 1979; pp. 174-175).

Species: "A smooth tufted, annual or perennial, aquatic herb with a very short rhizome; 10 to 50 cm tall, stemless; old plants often forming large clumps, but these are not connected; leaves 2 to 12.5 cm long, 0.5 to 10 cm wide, in very young plants without lamina; leaves of somewhat older plants with a floating linear or lanceolate blade; leaves of still older plants, ovate-oblong to broadly ovate, sharply acuminate, the base heart-shaped or rounded, shiny, deep green in color, with longitudinal veins; petioles soft, hollow, growing from buds at the base, leaf sheaths twisted together at the base, slightly reddish when young;; crown appears bulbous; inflorescence spikelike, basally opposite the sheath of the floral leaf, with a large bract arising from a thickened bundle on leaf stalk, about two-thirds of the way up the stalk from the base; flowers three to 25, opening simultaneously or in quick succession; on pedicels 4 to 25 mm long; perianth 11 to 15 mm long; petals six, violet or lilac blue, spreading at flowering, afterwards spirally contorted; stamens six, one with a lateral obliquely erect tooth; ovary with a long style; capsule about 1 cm, splitting between the partitions into three valves; seeds numerous, longitudinally ribbed.  The spikelike inflorescence which is opposite the floral leaf and the one stamen with a lateral oblique erect tooth are distinguishing characteristics.  The plant may be very variable and for that reason may be misidentified (Holm et al., 1977; p. 338).

"Stems usually inconspicuous, obliquely erect, roots usually pale purplish blue, spongy.  Leaves variable, blades linear to ovate, usually 5-10 cm long, 1.5-3 cm wide, apex acuminate, base rounded or cordate, cauline leaves smaller. Flowers few to numerous in racemes 2-4 cm long, peduncles emerging from the sheath of the upper-most leaf, 2-10 mm long, pedicels 3-6 mm long; perianth lobes purplish blue, oblong, 8-12 mm long; stamens 6, 1 larger than others.  Capsules ellipsoid, ca. 1 cm long.  Seeds oblong, with 8-12 longitudinal ribs" (Wagner et al., 1999; pp. 1606, 1913).

Key to species:

M. vaginalis: "Rhizome short; leaf blades of adult plants emersed, ovate-oblong to broadly ovate, obtuse or rounded or truncate-cordate at base, 2-12.5 x 0.5-10 cm, the basal lobes if present broadly rounded; flowers 3-25, expanding simultaneously or essentially so; perianth 11-15 mm long."

M. hastata: "Rhizome well developed, branched; leaf blades of adult plants usually with a sagittate or hastate base, 7-25 x 5-20 cm, the basal lobes divergent; flowers 15-60, not expanding simultaneously; perianth 15-18 mm long"  (Smith, 1979; pp. 174-175).

 Illustration by International Rice Research Institute (IRRI) courtesy Ecoport.

Habitat/ecology:  "An annual or pseudoannual in flooded ricefields, but may grow as a perennial in constantly flooded areas.  It can be found from 0 to 1,500 m altitude in Indonesia.  The plant roots in mud and its upper portions grow above the water" (Holm et al., 1977; p. 340).  In Hawai‘i, "naturalized in taro paddies and slow-moving streams, 0-30 m" (Wagner et al., 1999; p. 1606).  "In Fiji this species occurs as an adventive, as well as an ornamental, near sea level, although elsewhere it is found up to 1,500 m or higher.  It is often locally abundant in stagnant backwaters or rivers, in open drains, rice fields, swampy places, ditches, and wet pastures" (Smith, 1979; pp. 174-175).

Propagation:  Seed

Native range:  Malesia, Okinawa, Japan and Taiwan (Wagner et al., 1999; p. 1606).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Fiji Fiji Islands	Ovalau Island	introduced invasive cultivated	Smith, Albert C. (1979) (pp. 174-175) Voucher cited: Smith 7669
Fiji Fiji Islands	Viti Levu Island	introduced invasive cultivated	Smith, Albert C. (1979) (pp. 174-175) Vouchers cited: Vaughan 3163, Vaughan 3369, DA 10106, DA 9496, DA 10016, DA 9599, DA 10966, DA 10569, DA 10589, DA 10613, DA 6086
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, Warren L./Herbst, Derral R. (1995) (p. 23) Voucher cited: Stemmermann & Luce 7174 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1606) Voucher cited: Suehiro s. n. (BISH)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Oppenheimer, Hank (2011) (p. 9) Voucher cited: Oppenheimer & Perlman H100903 (BISH, PTBG)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 1606) Voucher cited: Suehiro s. n. (BISH)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands	native	Merrill, Elmer D. (1925) (pp. 200-201) At low and medium altitudes; common in open wet places, rice paddies, swamps, etc.
Solomon Islands Solomon Islands	Solomon Islands		Swarbrick, John T. (1997) (p. 94)
Solomon Islands Solomon Islands	Solomon Islands	native	Hancock, I. R./Henderson, C. P. (1988) (p. 92)

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)	Australia (continental)		Hafliger, E. (1092) (p. 99)
Cambodia Cambodia	Cambodia (Kingdom of)		Waterhouse, D. F. (1993) (pp. 67, 78)
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Rice fields, ditches, ponds, swamps; near sea level to 1500 m. Throughout China.
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 356) In paddy field or wet places.
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan Japan	Japan	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South Korea South Korea	South Korea (Republic of)		Holm, Leroy G./Plucknett, D. L./Pancho, J. V./Herberger, J. P. (1977) (p. 341)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Negara Brunei Darussalam Brunei	Brunei (Negara Brunei Darussalam)		Waterhouse, D. F. (1993) (pp. 67, 78)
Singapore Singapore	Singapore (Republic of)		Waterhouse, D. F. (1993) (pp. 67, 78)
Singapore Singapore	Singapore (Republic of)	uncertain if introduced invasive	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 61) Weed of uncertain origin
Taiwan Taiwan Island	Taiwan Island		Li-ying, Li/Ren, Wang/Waterhouse, D. F. (1997) (p. 173)
Thailand Thailand	Thailand (Kingdom of)		Waterhouse, D. F. (1993) (pp. 67, 78)
United States (west coast) United States (west coast states)	USA (California)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)		Waterhouse, D. F. (1993) (pp. 67, 78)

Control: 

Biological:  Waterhouse (1994, pp. 167) lists natural enemies of the species.