生活型

herb

形態特徵

• Annual herbs, erect or ascending, monoecious, 50–80 cm tall.
• Leaves glabrous to subglabrous, more or less fleshy; blades rhombic-ovate, 8–12 cm long, 7–9 cm wide, cuneate at base, obtuse at apex, the apex notched, with a fine mucuro; petioles up to 16 cm long, green flushed with purplish red.
• Flowers clustered into axillary or terminal spikes or panicles, the terminal inflorescence usually paniculate, 15–25 cm long, with puberulent rachis, the apical branches 4–10 mm wide, drooping. Male flowers restricted to the tips of the spike; bracts deltoid-ovate, 1.4–1.8 mm long and 0.6–1 mm wide, with a erect awn about 0.8 mm long; tepals 5, oblong-elliptic with pungent tip, outer tepals 2.3–3 mm long and 1 mm wide, inner ones 1.8–2 mm long and 0.6–0.8 mm wide, anthers yellow, 1 mm long, filament white, 0.8 mm long. Female flowers scattered in the spike except the spike-tips; bracts ovate to deltoid-ovate, 1.5–2 mm long and 0.8 mm wide; tepals 5, ovate to oblong-elliptic, more or less with pungent tips, 1.5–2 mm long and 0.6–0.8 mm wide; pistils 2–2.3 mm long, stigmas 3, reflexed, 0.8 mm long, style 0.5 mm long, ovary ovoid, 1 mm long and wide.
• Utricles, ovoid-urceolate, 1.5 mm long, with a inflated beak below the style base, circumscissile, the lid 1 mm long. Seeds lens-shaped, 1 mm across, reddish brown.

分布

• 世界 : Native of the New World, but is now widely naturalized in the tropics and subtropics.

引證標本

HUALIEN: Hualien City, Chen s. n. (NHU).

引用文獻

• Shih-Huei Chen and Ming-Jou Wu, Taiwania 52(1): 59-69. 2007.