''Dimeresia'' is a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

genus in the sunflower family containing the single species ''Dimeresia howellii'', known by the common name doublet.Calflora: ''Dimeresia howellii''
/ref>

Distribution

This uncommon plant is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to an area of the

Great Basin The Great Basin is the largest area of contiguous endorheic basin, endorheic watersheds, those with no outlets, in North America. It spans nearly all of Nevada, much of Utah, and portions of California, Idaho, Oregon, Wyoming, and Baja California ...

region in the western United States, in northeastern

California California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...

, southeastern

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

, southwestern

Idaho Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...

, and northwestern

Nevada Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...

.Jepson eFlora: ''Dimeresia howellii''
/ref>Biota of North America Program 2013 county distribution map
/ref> It grows in dry volcanic soils, primarily on the

Modoc Plateau __NOTOC__ The Modoc Plateau lies in the northeast corner of California as well as parts of Oregon and Nevada. Nearly of the Modoc National Forest are on the plateau between the Medicine Lake Highlands in the west and the Warner Mountains in the ...

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)
* Chaenactideae Flora of California Flora of Nevada Flora of Oregon Flora of the Great Basin Endemic flora of the United States ~ Monotypic Asteraceae genera Flora without expected TNC conservation status {{Asteroideae-stub