Dimeresia is a monotypic genus in the sunflower family containing the single species Dimeresia howellii, known by the common name doublet.Calflora: Dimeresia howelliiGray, Asa. 1886. Synoptical Flora of North America 1(2): 448–449Tropicos, Dimeresia − A. Gray
Distribution This uncommon plant is endemic to an area of the Great Basin region in the western United States, in northeastern California, southeastern Oregon, southwestern Idaho, and northwestern Nevada.Jepson eFlora: Dimeresia howelliiFlora of North America, Dimeresia A. Gray Biota of North America Program 2013 county distribution map
It grows in dry volcanic soils, primarily on the Modoc Plateau volcanic plain, at elevations of .
Description Dimeresia howellii is a very tiny annual flowering plant rarely exceeding 4 centimeters in height or width. It forms a small tuft on the ground with several oval-shaped leaves, and is cobwebby at base and glandular above.
The inflorescence has tiny white to purple bell-shaped flowers each a few millimeters long. The flowering period is May to August.
References
External links Calflora Database: Dimeresia howellii (Doublet) USDA Plants Profile for Dimeresia howellii (doublet) Jepson Manual eFlora (TJM2) treatment of Dimeresia howellii UC CalPhotos gallery of Dimeresia howellii (doublet)