''Isocoma acradenia'' is a North American species of flowering plant in the family

Asteraceae The family Asteraceae, alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae w ...

known by the common name alkali goldenbush. It is native to the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, Ne ...

(

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 ...

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 ...

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

) and northwestern Mexico (

Sonora Sonora (), officially Estado Libre y Soberano de Sonora ( en, Free and Sovereign State of Sonora), is one of the 31 states which, along with Mexico City, comprise the Administrative divisions of Mexico, Federal Entities of Mexico. The state is d ...

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

). It grows in arid, sandy areas, particularly mineral-rich areas such as

alkali flats A dry lake bed, also known as a playa, is a basin or depression that formerly contained a standing surface water body, which disappears when evaporation processes exceeds recharge. If the floor of a dry lake is covered by deposits of alkaline c ...

and

gypsum Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula . It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard or sidewalk chalk, and drywall. ...

soils.Calflora taxon report, University of California, ''Isocoma acradenia'' (E. Greene) E. Greene, Desert isocoma, alkali goldenbush
/ref>SEINet, Southwestern Biodiversity, Arizona chapter
/ref>

Description

''Isocoma acradenia'' is a bushy subshrub reaching maximum heights of slightly over . It produces erect, branching stems which are a shiny pale yellowish white, aging to a yellow-gray. Along the tough, hard-surfaced stems are linear or oval-shaped glandular leaves long, sometimes with stumpy teeth along the edges. They are gray-green and age to pale gray or tan. The

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

s along the top parts of the stem branches are clusters of four or five

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 ...

.Jepson Manual Treatment, University of California, (TJM93) of ''Isocoma acradenia''
/ref> Each head is a capsule encased in bumpy, glandular greenish

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 or ...

bearing many golden yellow disc florets at its mouth. Each disc floret is somewhat cylindrical and protruding. The fruit is an

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

a few millimeters long, with a yellowish pappus adding another few millimeters. ;Varieties *''Isocoma acradenia'' var. ''acradenia'' - Salt scrub, often with

creosote Creosote is a category of carbonaceous chemicals formed by the distillation of various tars and pyrolysis of plant-derived material, such as wood or fossil fuel. They are typically used as preservatives or antiseptics. Some creosote types were ...

- Arizona, California, Nevada, Sonora *''Isocoma acradenia'' var. ''bracteosa'' (Greene) G. L. Nesom - salt flats - southern Central Valley in California *''Isocoma acradenia'' var. ''eremophila'' (Greene) G. L. Nesom - sandy soils, dunes, etc. - Arizona, California, Nevada, Utah, Baja California, Sonora).

References

External links

Calflora Database: ''Isocoma acradenia'' (Alkali goldenbush, Desert isocoma)Jepson Manual eFlora (TJM2) treatment of ''Isocoma acradenia''UC CalPhotos gallery − ''Isocoma acradenia''

acradenia ''Acradenia'' is a genus of two species of tree or shrub in the family Rutaceae and is endemic to Australia. These plants have leaves that are trifoliate, arranged in opposite pairs and flowers that have five sepals, five petals and usually ten ...

Flora of the Southwestern United States Flora of Northwestern Mexico Flora of California Flora of the California desert regions Flora of the Sonoran Deserts Natural history of the California chaparral and woodlands Natural history of the Colorado Desert Natural history of the Mojave Desert Plants described in 1883 Taxa named by Edward Lee Greene Flora without expected TNC conservation status {{Astereae-stub