William Alfred Weber

Agnorhiza is a small genus of flowering plants in the family Asteraceae described as a genus in 1998. Its species had previously been considered members of either Wyethia or Balsamorhiza. The plants are native to California, with the range of one species (A. ovata) extending into northern Mexico. They are perennial herbs with sunflower-like flower heads 1 to 4 centimeters wide. Species Agnorhiza bolanderi - Bolander's mule's ears Agnorhiza elata - Hall's mule's ears Agnorhiza invenusta - Coville's mule's ears Agnorhiza ovata - southern mule's ears Agnorhiza reticulata - El Dorado mule's ears

Boechera perennans is a species of rockcress known as perennial rockcress. It is native to the southwestern United States and northern Mexico. It is a perennial herb growing up to 28 in (71 cm) tall. The basal leaves are hairy and often toothed, while the scattered upper leaves are up to 4 cm (1.6 in) long. Toward the top of the stem are small widely spaced purple or pink-purple flowers on long, thin stalks. These give way to the fruits, which are siliques: long, very narrow pods up to 6 centimeters long.

Boechera crandallii, or Crandall's rockcress, is found in Wyoming and Colorado where it is found on limestone chip-rock and stony areas, often among sagebrush. Flowering time is from May to June. According to chromosome counts by Rollins (1941 and 1966) B. crandalli has been identified as a diploid with n=7 which presumably reproduces sexually.

Askellia is a genus of Asian and North American plants in the tribe Cichorieae within the family Asteraceae. Species Askellia alaica (Krasch.) W.A.Weber - Tajikistan, Kyrgyzstan Askellia benthamii (C.B.Clarke) Sennikov - Jammu, Kashmir Askellia corniculata (Regel & Schmalh.) W.A.Weber - Tajikistan, Kyrgyzstan, Afghanistan, Pakistan, Jammu, Kashmir Askellia elegans (Hook.) W.A.Weber - Canada, United States (Alaska Montana Wyoming) Askellia flexuosa (Ledeb.) W.A.Weber - Tuva, Xinjiang, Mongolia, Inner Mongolia, Tibet, Qinghai, Gansu, Shanxi, Kazakhstan, Tajikistan, Kyrgyzstan, Afghanistan,

Torreyostellaria is a genus of flowering plants in the family Caryophyllaceae. It is monotypic, being represented by the single species Torreyostellaria jamesiana, commonly known as tuber starwort and sticky starwort, It is native to much of the western United States, where it can be found in sagebrush, coniferous forests, and many other types of habitat.

Boechera gunnisoniana, or Gunnison's rockcress, is a perennial herb of the family Brassicaceae (the mustards). It grows on windswept ridges as well as on stoney hillsides in west-central Colorado. The plant has many slender, erect stems which may reach a height of 15 cm. Flowering time is from May to June. According to chromosome counts, this species is diploid (n=7 as in all Boechera species) which probably reproduces sexually.

Vigethia is a genus of Mexican flowering plants in the tribe Heliantheae within the family Asteraceae. Species There is only one known species, Vigethia mexicana, called the Mexican green-eyed sunflower, native to the State of Nuevo León in northern Mexico.

Boechera pulchra, the beautiful rockcress, is a perennial plant in the mustard family (Brassicaceae) found in the Mojave Desert and other dry regions of southern and eastern California and Nevada, and the Colorado Plateau and Canyonlands region of the southwestern United States, mostly below 8,000 feet (2,400 m) elevation.

Boechera oxylobula, common name Glenwood Springs rockcress, is a plant species referred to as Arabis demissa in many older publications. The species is endemic to Colorado. It is known only from Garfield, Gunnison, Hinsdale, Lake, Mineral, Park, and Saguache counties in the central part of the state. It is found in open, rocky locations such as cliff faces, rocky slopes, and gravelly soil in brush. Boechera oxylobula is a perennial herb with several stems arising from a basal rosette. Leaves are linear, up to 2.5 mm (0.1 inches) wide. Flowers are white to pale lavender, borne in a terminal

Boechera lemmonii is a species of flowering plant in the family Brassicaceae known by the common name Lemmon's rockcress. It is native to western North America from Alaska to California to Colorado, where it grows in a number of rocky habitat types.

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Penstemon penlandii is a rare species of flowering plant in the plantain family known by the common names Penland penstemon and Penland beardtongue. It is endemic to Colorado, United States, where it is known only from a strip of land of approximately twelve square kilometers (4.6 sq mi) in central Grand County. It is a federally listed endangered species of the United States. The first recorded observances of P. penlandii were in the 1980s during surveys for Osterhout milkvetch, another rare local endemic. The two plants are found only in Middle Park, a valley with seleniferous badlands that

Packera franciscana (syn. Senecio franciscanus) is a rare species of flowering plant in the aster family known by the common name San Francisco Peaks groundsel, or San Francisco Peaks ragwort. It is endemic to Arizona in the United States, where it is known only from the San Francisco Peaks in Coconino County. It is threatened by recreational activities in its habitat. It is a federally listed threatened species of the United States.

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Agnorhiza reticulata (syn. Wyethia reticulata), known by the common name El Dorado County mule's ears, is a rare species of flowering plant found only in a small region of north-central California. Agnorhiza reticulata grows in the California interior chaparral and woodlands habitats of the Sierra Nevada foothills. It has been found in El Dorado, Sacramento, and Yuba Counties. The genetic diversity of the populations is probably low because they are often clonal, spreading via vegetative reproduction with rhizomes rather than sexual reproduction by seed. Some populations are also threatened

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Packera streptanthifolia is a species of flowering plant in the aster family known by the common name Rocky Mountain groundsel. It is native to western North America from Alaska to California to New Mexico, where it can be found in mountain habitat including woodlands and rocky slopes. It is a perennial herb producing usually one erect stem, sometimes a cluster of a few stems, 10 to 60 centimeters in maximum height. The spatula-shaped basal leaves have oval or lance-shaped blades on long petioles. They are thick, firm, and sometimes somewhat succulent. Leaves higher on the stem are smaller,

Packera schweinitziana, commonly called New England groundsel, is a species of flowering plant in the aster family (Asteraceae). It is native to eastern North America, where it is primarily found in eastern Canada and the northeastern United States, with disjunct populations in North Carolina and Tennessee on Roan Mountain. Its natural habitat is in sunny, wet areas, often in acidic soil. In the southeastern United States, its habitat is restricted to Appalachian balds. Packera schweinitziana is a perennial growing to around 70 cm tall, and is occasionally rhizomatous. It produces heads of

Packera plattensis, commonly known as prairie ragwort or prairie groundsel, is a species of the genus Packera and family Asteraceae. It used to be placed in the genus Senecio. Prairie groundsel is found throughout the tallgrass prairie region. It blooms fairly early for a prairie wildflower: from April to July depending on the climate. It is easily confused with golden ragwort (Packera aurea) which has a hairless stem and heart-shaped basal leaves, and Senecio integerrimus, which has leaves that are mostly entire instead of fern-like, and much larger basal leaves.

Packera obovata, commonly known as roundleaf ragwort, spoon-leaved ragwort, or roundleaf groundsel is an erect perennial herb in the Asteraceae (aster) family native to eastern North America. It was previously called Senecio obovatus. Basal and lower leaves are obovate with toothed margins, while upper leaves are pinnately divided. The ray flowers are yellow and the disk flowers orange-yellow, the inflorescences being held well above the foliage.

Packera multilobata is a species of flowering plant in the aster family known by the common name lobeleaf groundsel. It is native to the western United States from California to Wyoming to New Mexico, where it is common and can be found in many habitat types. It is an annual or perennial herb producing a single stem or a cluster of several stems up to about half a meter tall from a taproot and branching caudex unit. The leaves are divided into several lobes, often so deeply that they look like separate leaflets. The inflorescence is a wide array of flower heads lined with green or yellowish

Packera layneae, known by the common name Layne's ragwort and Layne's butterweed, is a rare species of flowering plant in the aster family.

Packera hesperia is a flowering plant in the aster family, Asteraceae. Commonly known as western ragwort and as serpentine groundsel, it is endemic to the Siskiyou Mountains, where it grows on serpentine soils. Conservation groups have identified this species as vulnerable, in part due to its limited geographic distribution.

Packera greenei is a species of flowering plant in the aster family known by the common name flame ragwort. It is endemic to northern California, where it is known from the North Coast Ranges and southern Klamath Mountains. It is a resident of dry mountain scrub habitat, often on serpentine soils. It is a perennial herb producing a single stem with a basal rosette of leaves from a rhizome. It generally grows 20 to 30 centimeters tall. The basal leaves have oval blades up to 5 or 6 centimeters long borne on long petioles. They are green, usually with purple undersides. Smaller leaves may occur

Packera fendleri is a species of flowering plant in the family Asteraceae known by the common name Fendler's ragwort. It is native to the southern Rocky Mountains, and is found in the states of Colorado, Wyoming and New Mexico, where it is a common plant that occurs in a variety of habitats. It is a perennial herb, reaching a maximum height of around 16 inches tall. It flowers between late May and early October, producing an inflorescence of 6–25 flower heads, each lined with 13 green phyllaries, and containing many disk florets and 6–8+ yellow ray florets.

Packera eurycephala is a species of flowering plant in the aster family known by the common name widehead groundsel. It is native to a section of the western United States encompassing southern Oregon, northern California, and northern Nevada. It can be found in dry habitat types, often in disturbed areas, and it favors serpentine soils. It is a perennial herb reaching a maximum height of 50 to 70 centimeters, its cluster of erect stems growing from a taproot and woody caudex unit. The leaves are up to 10 centimeters long and are made up of many narrow, lacy lobes. The plant is slightly to