Ragweeds are flowering plants in the genus Ambrosia in the aster family, Asteraceae. They are distributed in the tropical and subtropical regions of the Americas, especially North America, where the origin and center of diversity of the genus are in the southwestern United States and northwestern Mexico. Several species have been introduced to the Old World and some have naturalized and have become invasive species. In Europe, this spread is expected to continue, due to ongoing climate change.
Teucrium is a cosmopolitan genus of flowering plants in the mint family Lamiaceae, commonly known as germanders. Plants in this genus are perennial herbs or shrubs, with branches that are more or less square in cross-section, leaves arranged in opposite pairs, and flowers arranged in thyrses, the corolla with mostly white to cream-coloured, lobed petals.
Rubus odoratus, the purple-flowered raspberry, flowering raspberry, or Virginia raspberry, is a species of Rubus, native to eastern North America, from Nova Scotia west to Ontario and Wisconsin, and south along the Appalachian Mountains as far as Georgia and Alabama.
Passiflora lutea, commonly known as yellow passionflower, is a flowering perennial vine in the family Passifloraceae, native to the central and eastern United States. The vine has three-lobed leaves and small, yellowish-green, fringed flowers that appear in the summer, followed by green fruit that turn almost black at maturity. It grows in moist to wet habitats.
Packera obovata, commonly known as roundleaf ragwort, spoon-leaved ragwort, roundleaf groundsel, or squaw-weed, 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.
Ambrosia trifida, the giant ragweed, is a species of flowering plant in the family Asteraceae. It is native to North America, where it is widespread in Canada, the United States, and northern Mexico.
Sabatia, the rose gentians, is a genus of about 20 species of flowering plants in the family Gentianaceae, native to eastern and central North America, Central America, and the Caribbean.
Ambrosia acanthicarpa is a North American species of bristly annual plants in the family Asteraceae. Members of the genus Ambrosia are called ragweeds. The species has common names including flatspine bur ragweed, Hooker's bur-ragweed, annual burrweed, annual bur-sage, and western sand-bur. The plant is common across much of the western United States and in the Prairie Provinces of Canada.
Succisa pratensis, also known as devil's-bit or devil's-bit scabious, is a flowering plant in the honeysuckle family Caprifoliaceae. It differs from other similar species in that it has four-lobed flowers, whereas small scabious and field scabious have five lobes and hence it has been placed in a separate genus in the same family. It also grows on damper ground.
Ambrosia psilostachya is a species of ragweed known by the common names Cuman ragweed and perennial ragweed, and western ragweed.
Artemisia biennis is a species of sagebrush known by the common name biennial wormwood. It is a common and widely distributed weed, so well established in many places that its region of origin is difficult to ascertain. This species is most likely native to northwestern North America and naturalized in Western Europe, and eastern and southern North America.
Lessingia virgata is a species of flowering plant in the family Asteraceae known by the common name wand lessingia. It is endemic to California, where it is known from the eastern side of the Central Valley and adjacent Sierra Nevada foothills. It is a woolly, glandular annual herb growing up to about 60 centimeters tall with slender, spreading branches. The upper leaves are no more than a centimeter long, while the lower ones are longer and sometimes divided into lobes or teeth. The flower heads appear singly in leaf axils, each lined with purple-tipped, glandular, woolly phyllaries. The head is discoid, containing no ray florets but a few tubular light lavender to nearly white disc florets with long, narrow lobes. The fruit is an achene with a whitish pappus on top.
Ranunculus recurvatus, the blisterwort or hooked crowfoot, is a plant species of the genus Ranunculus in the family Ranunculaceae native to eastern North America. It is an early-flowering plant of moist deciduous woods from central Quebec south to Florida.
Sphaeromeria cana is a species of flowering plant in the family Asteraceae known by the common name gray chickensage. It is native to the western United States, where it is known from the Sierra Nevada, the adjacent desert ranges of eastern California and Nevada, and Steens Mountain of Oregon. It grows in dry, rocky mountain habitat, such as cracks and crevices, including the talus above the tree line. This is an aromatic subshrub with numerous erect branches growing up to 30 to 60 centimeters tall. It is gray-green in color and coated with woolly fibers. The leaves are linear or lance-shaped, the lower ones divided into lobes. The inflorescence is generally a cluster of flower heads lined with woolly phyllaries and containing yellow disc florets. There are no ray florets. The fruit is a ribbed achene about 2 millimeters long.
Ambrosia linearis is a species of flowering plant in the family Asteraceae known by the common names streaked bur ragweed, Colorado bursage, linear-leaf bursage, and plains ragweed. It is endemic to east-central part of the state of Colorado in the United States, where it occurs in Elbert, Pueblo, El Paso, Cheyenne, Crowley, Kiowa and Lincoln Counties.
Ratibida pinnata is a species of flowering plant in the family Asteraceae known by the common names pinnate prairie coneflower, gray-head coneflower, yellow coneflower, and prairie coneflower. It is native to the central and eastern United States and Ontario in Canada.
Ambrosia salsola, commonly called cheesebush, winged ragweed, burrobush, white burrobrush, and desert pearl, is a species of perennial shrub in the family Asteraceae native to deserts of the southwestern United States and northwestern Mexico.
Ambrosia grayi, the woollyleaf bur ragweed, is a North American species of plants in the family Asteraceae. It is native to the west-central part of the Great Plains of the United States, in the states of Nebraska, Kansas, Colorado, New Mexico, Oklahoma, and Texas.
Ambrosia monogyra is a species of flowering plant in the sunflower family commonly known as the singlewhorl burrobrush, leafy burrobush, slender burrobush, and desert fragrance. Ambrosia monogyra is native to North America and is typically found in canyons, desert washes, and ravines throughout arid parts of the southwestern United States and northern Mexico. This species has green, threadlike leaves that emit a distinctive odor when crushed, and flowers from August to November. The fruits have distinctive wings in their middle that aid in dispersion through wind and water.
Cuscuta denticulata, commonly known as desert dodder or small-toothed dodder, is a thin, yellow to orange, parasitic annual vine in the morning glory family (Convulvulaceae), native to the deserts of the south-western United States and northern Mexico.
