Trillium undulatum (Painted Trillium) is a wildflower of the genus trillium found from Ontario in the north to the Carolinas in the south and from Michigan in the west to Nova Scotia in the east. It is also known as painted lady or trille ondulé. It demands strongly acidic, humus-rich soils and tends to be found in the shade of acid-loving trees such as eastern white pine, red maple, red spruce and balsam fir. Although the soils that support it have low base saturation, this species was found to have relatively high levels of calcium, magnesium, and especially potassium in its foliage.
- "Trillium undulatum". NatureServe Explorer. NatureServe. Retrieved 2008-05-02.
- Trillium undulatum World Checklist of Selected Plant Families 2011-12-03
- T.G. Siccama, F.H. Bormann and T.E. Likens. The Hubbard Brook Ecosystem Study: Productivity, Nutrients and Phytosociology of the Herbaceous Layer. Ecological Monographs Vol.40, No. 4, Autumn 1970.