Genus of aquatic herbs of temperate and tropical regions having sagittate or hastate leaves and white scapose flowers .
生长于温带或热带地区的一个水生草本植物属，叶箭头状或戟形，花具花葶，白色花。
Inflorescence terminal or lateral , scapose or sessile , a panicle , raceme , spike , or head , sometimes reduced to solitary , pseudolateral flowers ; bracts usually brightly colored and conspicuous .
