''Isocoma arguta'' is a rare species of flowering plant in the family

Asteraceae Asteraceae () is a large family (biology), family of flowering plants that consists of over 32,000 known species in over 1,900 genera within the Order (biology), order Asterales. The number of species in Asteraceae is rivaled only by the Orchi ...

known by the common name Carquinez goldenbush. It has been found only in Solano and Contra Costa Counties in

California California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...

, where it grows in the Sacramento-San Joaquin River Delta.Calflora taxon report, University of California, ''Isocoma arguta'' E. Greene, Carquinez goldenbush
It is a resident of

Suisun Marsh Located in northern California, the Suisun Marsh ( ) has been referred to as the largest brackish water marsh on west coast of the United States of America. The marsh land is part of a tidal estuary, and subject to tidal ebb and flood. The marsh ...

. It thrives on alkali flats and other mineral-rich soils.

Description

''Isocoma arguta'' is a compact

subshrub A subshrub (Latin ''suffrutex'') or undershrub is either a small shrub (e.g. prostrate shrubs) or a perennial that is largely herbaceous but slightly woody at the base (e.g. garden pink and florist's chrysanthemum). The term is often interch ...

reaching about half a meter-1.5 feet (20-60 inches) tall and wide with erect, multibranched stems. The hairy stems bear small gray-green, nonfleshy, glandular leaves each less than long.Flora of North America, ''Isocoma arguta'' Greene, 1894. Contra Costa jimmyweed , Carquinez or suisun goldenbush
/ref> The

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

s hold clusters of thick, knobby

flower heads A pseudanthium (; : pseudanthia) 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, composite flowers ...

. Each head is a capsule of layered greenish glandular

phyllaries In botanical terminology, a phyllary, also known an involucral bract or tegule, is a single bract of the involucre of a composite flower. The involucre is the grouping of bracts together. Phyllaries are reduced leaf-like structures that form one o ...

with an array of 10-13 cylindrical, protruding golden yellow disc florets at one end. There are no ray florets.

References

External links

Calflora Database: ''Isocoma arguta'' (Carquinez goldenbush, Carquinez isocoma)Jepson Manual eFlora (TJM2) treatment of ''Isocoma arguta''UC CalPhotos gallery − ''Isocoma arguta''
arguta Endemic flora of California Natural history of Solano County, California Natural history of the Central Valley (California) Endemic flora of the San Francisco Bay Area Plants described in 1894 Taxa named by Edward Lee Greene Critically endangered flora of California {{Astereae-stub