Revised 2015-02-23: This was one of my earliest blog posts, first published in June 2006. I've overhauled it to 1) meet my current technical standards, and 2) improve the content based on the latest available information.
Chelidonium majus, Celandine or Greater Celandine, is a biennial (blooming the second year) herbaceous plant in the Papaveraceae, the Poppy family. It is native to Eurasia. It's the only species in the genus.
It's invasive outside its native range, and widespread across eastern North America. It emerges early in the Spring, before our native wildflowers emerge, and grows quickly to about 2 feet. That's one of the clues to identification. It's also one of the reasons why it's so disruptive. The rapid early growth crowds and shades out native Spring ephemerals.
Greater celandine is one of the first weeds I identified when we bought our home in 2005 and I started the current gardens. Here's my collection of photos from the garden's second year, in 2006, highlighting the characteristics that help to identify this plant. The photos (click for embiggerization) show: