Abstract

We document the naturalization of the New World Helianthus debilis Nuttall subsp. cucumerifolius (Torrey & A. Gray) Heiser in central Taiwan. A taxonomic treatment, line drawings, and color photographs of this species from the wild are provided to aid in identification. This represents the first report of Helianthus species in Taiwan. The colony of H. debilis subsp. cucumerifolius was first observed in Taiwan in 1999. During our field survey in 2007 we witnessed the significant range expansion though the coast of Changhua County. The potential of H. debilis subsp. cucumerifolius to become an invasive species in Taiwan is worthy of attention.

中文摘要

本文首次報導原產北美洲，目前已歸化於臺灣彰化縣沿海附近的瓜葉向日葵(菊科)，描述其形態特徵、地理分布及生育地環境，並提供彩色圖片與線繪圖以資辨識。作者等於1999 年即已發現當地大量之瓜葉向日葵族群，目前再進行調查發現其分布範圍已有顯著擴張。瓜葉向日葵為臺灣新歸化植物，本屬亦為臺灣新記錄屬。

Keyword: Asteraceae, Helianthus debilis subsp. cucumerifolius, Naturalized plant, Taiwan. 菊科、瓜葉向日葵、歸化植物、臺灣。