''Deiandra arida'' (formerly ''Hemizonia arida''), also called Red Rock tarplant, is a rare

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 ...

annual plant An annual plant is a plant that completes its life cycle, from germination to the production of seeds, within one growing season, and then dies. The length of growing seasons and period in which they take place vary according to geographical ...

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 ...

.Mojave Desert Wildflowers, Pam MacKay, 2nd Ed. 2013, p. 189

Habitat and range

''Deiandra arida'' occurs on

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay par ...

and

volcanic soils The soil composition of vineyards is one of the most important viticultural considerations when planting grape vines. The soil supports the root structure of the vine and influences the drainage levels and amount of minerals and nutrients that the ...

and in

desert dry wash Desert dry wash is a North American desert vegetation type (or biome) occurring in the flat bottoms of canyons and drainages that lack water at or near the surface most of the year, and are subject to periodic severe flooding events.Pam MacKay, Moj ...

from 1,000-3,000 feet (300–900 m) in elevation. It is known from only 10 sites in the Red Rock Canyon State Park area of the

Mojave Desert The Mojave Desert ( ; mov, Hayikwiir Mat'aar; es, Desierto de Mojave) is a desert in the rain shadow of the Sierra Nevada mountains in the Southwestern United States. It is named for the indigenous Mojave people. It is located primarily in ...

Kern County Kern County is a county located in the U.S. state of California. As of the 2020 census, the population was 909,235. Its county seat is Bakersfield. Kern County comprises the Bakersfield, California, Metropolitan statistical area. The county sp ...

.Flora of North America, ''Deinandra arida'' (D. D. Keck) B. G. Baldwin, Novon. 9: 467. 1999.
/ref>

Growth pattern

It is a branched

annual Annual may refer to: * Annual publication, periodical publications appearing regularly once per year **Yearbook ** Literary annual * Annual plant * Annual report * Annual giving * Annual, Morocco, a settlement in northeastern Morocco * Annuals (b ...

growing from 1' to 3' (30–90 cm) tall.

Leaves and stems

Lower leaves are inversely lanceolate and hairless, with toothed margins. Upper leaves are without teeth (

entire Entire may refer to: * Entire function, a function that is holomorphic on the whole complex plane * Entire (animal), an indication that an animal is not neutered * Entire (botany) This glossary of botanical terms is a list of definitions of ...

) at the outside edge, and are covered in sparse, short, stiff hairs, giving it a bristly feel.

Flowers and fruits

Flower head 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 ...

s grow in flat-topped clusters at the tops of stems.

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 ...

have 18-25 yellow

disk flowers 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 ...

, with 5-10 yellow

ray flowers 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 ...

. Bristly

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 ...

halfway enclose the akenes.

References

External links

Calflora Database: ''Deinandra arida'' (Red rock tarplant) Jepson eFlora (TJM2) treatment of ''Deinandra arida''Missouri Botanical Garden Herbarium specimen photo, isotype of Hemizonia arida/Deinandra arida
* {{Taxonbar, from=Q15571691 arida Endemic flora of California Flora of the California desert regions Natural history of the Mojave Desert Natural history of Kern County, California Plants described in 1958 Critically endangered flora of California