''Stylocline citroleum'' is a rare species of flowering plant in the family
Asteraceae known by the common name oil neststraw.
Description
This inconspicuous annual herb produces a grayish, trailing, forking stem no more than long. The grayish, woolly, pointed leaves are up to long. The
inflorescence bears spherical
flower heads
A pseudanthium (Greek for "false flower"; ) is an inflorescence that resembles a flower. The word is sometimes used for other structures that are neither a true flower nor a true inflorescence. Examples of pseudanthia include flower heads, compos ...
just a few millimeters long with tiny, rough-haired
phyllaries and scaly, woolly florets. It is hard to tell apart from other ''Stylocline'' because its defining characteristics are microscopic.
[
]
Distribution
It is endemic to Kern County, California, where it is known from about 46 occurrences on and around the Elk Hills Oil Field. The occurrences are patchy and variable in size, and some sources consider them to be part of a single widely spread metapopulation
A metapopulation consists of a group of spatially separated populations of the same species which interact at some level. The term metapopulation was coined by Richard Levins in 1969 to describe a model of population dynamics of insect pests in ...
.[The Nature Conservancy]
/ref> The species has been collected from coastal San Diego County, but any occurrences there are probably now extirpated.[Flora of North America]
/ref>
The plant has been known for over one hundred years, and the type specimen was collected in 1935, but it was not described to science as a distinct species until 1992.[San Joaquin Valley Endangered Species Recovery Program]
CSU Stanislaus.[Morefield, J. D. (1992). Three new species of ''Stylocline'' (Asteraceae:Inuleae) from California and the Mojave Desert. ''Madroño'' 39:114-130.]
''Stylocline citroleum'' grows in the valley saltbush scrub ecosystem in the sandy flats and clay soils of the San Joaquin Valley in areas developed into oil field
A petroleum reservoir or oil and gas reservoir is a subsurface accumulation of hydrocarbons contained in porous or fractured rock formations.
Such reservoirs form when kerogen (ancient plant matter) is created in surrounding rock by the presence ...
s, the inspiration for the common
Common may refer to:
Places
* Common, a townland in County Tyrone, Northern Ireland
* Boston Common, a central public park in Boston, Massachusetts
* Cambridge Common, common land area in Cambridge, Massachusetts
* Clapham Common, originally com ...
and scientific name
In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...
s of the species.[ The plant probably evolved as a hybrid of mountain neststraw (''Stylocline gnaphaloides'') and California filago ('' Filago californica''), and it is almost always found growing alongside one or both of its parent species.][
]
References
External links
Jepson Manual Treatment - ''Stylocline citroleum''
{{Taxonbar, from=Q7629671
citroleum
Endemic flora of California
Natural history of the Central Valley (California)
Natural history of Kern County, California
Plants described in 1992