Hecastocleis is a genus of low thorny shrubs with stiff branches, assigned to the daisy family. At the tip of each of the branches, inflorescences are subtended by oval, thorny, whitish to greenish bracts that enclose several flower heads which each contain only one pinkish bud, opening into a white corolla. It contains but one species, Hecastocleis shockleyi, the only representative of the tribe Hecastocleideae, and of the subfamily Hecastocleidoideae. Its vernacular name is prickleleaf. It is confined to the southwestern United States.
Brickellia incana is a North American species of flowering plant in the family Asteraceae known by the common name woolly brickellbush. It is native to the Mojave Desert and Sonoran Desert in the southwestern United States, in California, Nevada, and Arizona.
Sphaeralcea grossulariifolia is a species of flowering plant in the mallow family known by the common name gooseberryleaf globemallow. It is native to the western United States, where it can be found in the Great Basin and surrounding regions. It grows in sagebrush, woodlands, playas, and the canyons of the upper Colorado River. It is common in disturbed areas, such as habitat recently cleared by wildfire.
Stenotus lanuginosus is a species of flowering plant in the family Asteraceae known by the common names woolly mock goldenweed and woolly stenotus.
Suaeda taxifolia is a species of flowering plant in the family Amaranthaceae known by the common name woolly seablite.
Tetracoccus hallii is a species of flowering shrub in the family Picrodendraceae, known by the common names Hall's shrubby-spurge and Hall's tetracoccus.
Tetradymia argyraea is a species of flowering plant in the aster family known by the common names striped cottonthorn and striped horsebrush. It is native to the desert mountains of the southwestern United States, particularly of California, Nevada, and Arizona, where it grows in desert woodland habitat. It is a woolly, spiny shrub growing one half to nearly two meters in maximum height. The erect stems are white-woolly except for bare stripes at intervals. The leaves are linear in shape and harden as they age, becoming spiny. The larger leaves are woolly and there are clusters of smaller, threadlike leaves which may be hairless. The inflorescence bears two to five flower heads which are each enveloped in five thick phyllaries coated in white woolly hairs. Each head contains five pale yellow flowers each around a centimeter long. Flowers are produced in summer, as late as September. The fruit is an achene a few millimeters long tipped with a pappus of bristles.
Tetradymia argyraea is a species of flowering plant in the aster family known by the common names spineless horsebrush and gray horsebrush. It is native to western North America.
Tetradymia comosa is a species of flowering plant in the aster family, known by the common name hairy horsebrush.
Tetradymia glabrata is a species of flowering plant in the aster family known by the common name littleleaf horsebrush. It is native to the western United States, especially the Great Basin and Mojave Desert. Its habitat includes sagebrush, woodlands, and scrub. It is an erect, bushy shrub growing to a maximum height over one meter, its stems coated unevenly in white woolly fibers with many bare strips. The narrow, pointed leaves are usually no more than a centimeter long and most occur in clusters along the branches. The inflorescence bears up to seven flower heads which are each enveloped in four woolly phyllaries. Each head contains four yellow cream flowers each around a centimeter long. The fruit is a hairy, ribbed achene with a pappus of bristles.
Tetradymia spinosa is a species of flowering plant in the aster family known by the common name shortspine horsebrush. It is native to the western United States, especially the basins and plateaus west of the Rocky Mountains. It grows in sagebrush, woodlands, and scrub habitat, often among shadscale in alkaline areas such as playas. It is a bushy shrub with many branches coated in woolly white fibers and growing to a maximum height around a meter. The leaves are narrow, curving, and hooklike, hardening into sharp spines up to 2.5 centimeters long. The inflorescence bears one or two flower heads which are each enveloped in four to six woolly phyllaries. Each head contains up to 8 tubular yellow disc flowers up to 1 cm long. The fruit is a densely hairy achene which may be nearly 2 cm long, including its pappus of long bristles.
Tetradymia stenolepis is a species of flowering plant in the aster family known by the common name Mojave cottonthorn. It is native to the deserts around the intersection of Arizona, Nevada, and eastern California, where it grows in woodland and scrub habitat on sandy and gravelly substrates. It is a bushy shrub with many branches coated in woolly white fibers and growing to a maximum height just over a meter. The narrow leaves are 2 or 3 centimeters long and harden into straight, sharp spines. Clusters of woolly leaves grow near the spines. The inflorescence bears up to 7 flower heads which are each enveloped in four or five woolly phyllaries. Each head contains up to four or five tubular yellow flowers each around a centimeter long. The fruit is a hairy achene which may be nearly 2 centimeters long, including its pappus of long bristles.
Tricardia is a monotypic genus of flowering plants in the borage family containing the single species Tricardia watsonii, which is known by the common name threehearts. It is native to the southwestern United States, where it grows in deserts and mountains in sandy open habitat, often beneath shrubs. It is a perennial herb growing from a taproot and a woody caudex covered with the shreddy remains of previous seasons' herbage. It produces several erect stems up to about 40 centimeters tall. Most of the leaves are located in a basal rosette about the caudex. They are lance-shaped and coated thinly in woolly hairs. They are up to 9 centimeters long and are borne on petioles. A few smaller leaves occur higher on the stem. Flowers occur in a loose cyme at the top of the stem. Each has a calyx of five sepals. The outer three are heart-shaped and green to pink or purple in color, and the inner two are much smaller and narrower. The flower within is bell-shaped, white with central purple markings, and roughly half a centimeter wide. The fruit is a capsule just under a centimeter long which contains 4 to 8 seeds.
Trichostema parishii is a species of flowering plant in the mint family known by the common name Parish's bluecurls.
Trifolium andersonii is a species of clover known by the common names fiveleaf clover and Anderson's clover. It is native to the western United States, particularly the Great Basin and adjacent high mountain ranges, including the Sierra Nevada. It was named after Charles Lewis Anderson by Asa Gray.
Trifolium macrocephalum is a species of clover known by the common name largehead clover or bighead clover.
Wyethia mollis is a species of flowering plant in the family Asteraceae known by the common name woolly mule's ears. The plant is hairy to woolly in texture, sometimes losing its hairs with age.
Schoenocrambe argillacea is a rare species of flowering plant in the mustard family known by the common names clay reed-mustard, Uinta Basin plainsmustard, and clay thelypody.
Tetradymia nuttallii is a species of flowering plant in the aster family known by the common name Nuttall's horsebrush. It is native to the western United States, where it occurs in Nevada, Utah, Wyoming, and Colorado.
Ericameria parryi is a species of flowering plant in the family Asteraceae known by the common name Parry's rabbitbrush. It is native to much of the western United States.
