Isotria verticillata, the Large whorled pogonia orchid, is a species native to much of the eastern part of the United States, from Maine to Texas. It is found in acidic soils in forests and in peat bogs.Isotria verticillata is a terrestrial herb spreading by underground rhizomes. Leaves are green above, waxy and a bit whitened below. Flowers are yellowish-green, up to 110 mm (4.3 inches) across.