tall annual marsh elder common in moist rich soil is central North America that can cause contact dermatitis; produces much pollen that is a major cause of hay fever.

• 一种一年生的、高大的沼生接骨木，它常见于北美中部的潮湿沃土上，造成接触性皮炎；产生许多花粉，是引起花粉热的主要原因。