Monochoria hastata (L.) Solms-Laub.
Pontederiaceae
arrowleaved monochoria
seed
Fruit a capsule with numerous seeds. Seeds terete, elliptic to broadly elliptic, occasionally broadly oblong in outline, 0.6–0.83 mm long, 0.4–0.57 mm in diameter; with ca. 12 longitudinal lines or low ridges evenly spaced around seed. Testa light yellow to orange-yellow, frequently darker reddish on one or both ends, with glistening, fine horizontal striations in between ridges. Hilum terminal, often with persistent funiculus remnant to 0.1 mm long; chalazal end obtuse or sometimes even depressed and often darker in color. Embryo axile-linear, extending almost to both poles; endosperm readily visible.
Seeds develop from an anatropous ovule, characteristic in the Pontederiaceae, resulting in both ends being distinctly featured. The chalazal end is opposite the hilar end.
Eichhornia crassipes (Sw.) Kunth (non-FNW)
Heteranthera limosa (Sw.) Willd. (non-FNW)
Eichhornia azurea (Sw.) Kunth
Monochoria vaginalis (Burm. f.) C. Presl
tropical Asia, from India through Southeast Asia; also China, Northern Australia, Fiji, and Hawaii
shallow water; freshwater pools, mudflats in rivers, ditches, canal banks, swampy ground, rice fields
Monochoria hastata is an attached aquatic herb with emersed leaves to 100 cm tall. Although it is not as common nor as serious a weed as M. vaginalis, it is widespread in tropical Asia and is an aggressive weed of lowland rice in Fiji, Malaysia, the Philippines and Indonesia. Monochoria hastata has been grown as an ornamental in water gardens, and the entire plant except its roots is eaten in India.