Monochoria hastata (L.) Solms-Laub., Pontederiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Common name(s): [more details]

Chinese: jian ye yu jiu hua

English: arrow-leaf monochoria, hastate-leaf pondweed, monochoria

Tagalog: calaboa

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; p. 175).

Species:  "A smooth, erect, aquatic, perennial herb, 30 to 100 cm tall; with a well-developed, branched rhizome; old plants form large groups which may be connected by underground stolons; leaves of mature plants 5 to 25 cm long, 4 to 20 cm wide, almost always with a sagittate or hastate, rarely  with a cordate, base, basal lobes diverging, either with acuminate tips or not, borne on long sheathlike petioles; inflorescence in spikelike racemes; flowers 15 to 60, not expanding simultaneously, lower flower stalks (pedicels) 15 to 30 mm long, higher ones 7 to 20 mm; perianth light blue, 15 to 18 mm long; fruit enclosed by the perianth, about 1 cm long; seeds numerous, light brown, with faint longitudinal lines, blunt at one end, rounding at the other, minute"  (Holm et al., 1977; p. 340).

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; p. 175).

Habitat/ecology:  "In Java, M. hastata grows from 0 to 700 m elevation in freshwater pools, mudflats in rivers, ditches and rice fields, and along canal banks (Backer and Bakhuizen van den Brink, Jr. 1968).  In Fiji, it grows in shallow water, swampy ground, open drains, rice fields, or in very wet soils (Parham, 1958)" (Holm et al., 1977; p. 340). In Fiji, "sparsely cultivated" (Smith, 1979; p. 175).

Propagation:  Seed. "Many seeds are produced by each plant" (Holm et al., 1977; p. 340).

Native range:  Southeastern Asia and Malesia (Smith, 1979; p. 175), 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
Fiji Fiji Islands	Viti Levu Island	introduced cultivated	Smith, Albert C. (1979) (p. 175) Voucher cited: DA 12290
New Guinea (Indonesia and Papua New Guinea) New Guinea Island	New Guinea Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands		Merrill, Elmer D. (1925) (p. 200) In open wet lands, swamps, etc., at low and medium altitudes.

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)	Northern Territory	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Cambodia Cambodia	Cambodia (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Pools, rice fields, ditches; 100-700 m. Guangdong, Guizhou, Hainan, Yunnan
China China	Hong Kong	native	Wu, Te-lin (2001) (p. 356) In paddy fields and ponds.
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013) Java
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore Singapore	Singapore (Republic of)	native	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
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Comments:  An ornamental used in water gardens (Smith, 1979; p. 175).

Control:  If you know of control methods for Monochoria hastata, please let us know.