Taxonomy and distribution of invasive Galinsoga Ruiz & Pavón in China

Galinsoga parviflora Cav and G．quadriradiata Ruiz & Pavón specimens were examined to study their morphological characters and distribution in China．Two species of the genus Galinsoga, G．parviflora Cav．and G．quadriradiata Ruiz & Pavón, both invasive plants, were found in China．Some distinctive characters may be used to distinguish the two．For G．parviflora, stems were nearly glabrous or sparsely pilose; ray floret corollas were small, being singular, bifid or trifid; pappi were either absent or much shorter than tubes．For G．quadriradiata, stems were moderately or densely pilose; ray florets corollas were large, being trifid; pappi were almost as long as tube．Both G．parviflora and G．quadriradiata have been found in most areas in China, their distributions overlapped．G．parviflora was found centralized in the Southwest, Northeast, and east areas of North China．G．quadriradiata was found dispersed widely, in the Southwest, Central, East China, south areas of North China, and south areas of Northeast China．