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

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

Habitat and range

''Deiandra arida'' occurs on clay 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 in Kern County, California.Flora of North America, ''Deinandra arida'' (D. D. Keck) B. G. Baldwin, Novon. 9: 467. 1999.
/ref>

Growth pattern

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

Flowers and fruits

Flower heads 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. Bristly phyllaries halfway enclose the

akene 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 ...

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