Ambrosia psilostachya is a species of ragweed known by the common names Cuman ragweed and perennial ragweed,[3] and western ragweed.
The plant is widespread across much of North America (United States, Canada, and northern Mexico).[4] It is also naturalized in parts of Europe, Asia, Australia, and South America.[5] It is a common plant in many habitat types, including disturbed areas such as roadsides.[6][7][8][9][10]
Ambrosia psilostachya is an erect perennial herb growing a slender, branching, straw-colored stem to a maximum height near two meters, but more often remaining under one meter tall. Leaves are up to 12 centimeters long and vary in shape from lance-shaped to nearly oval, and they are divided into many narrow, pointed lobes. The stem and leaves are hairy.[6]
The top of the stem is occupied by an inflorescence which is usually a spike. The species is monoecious, and the inflorescence is composed of staminate (male) flower heads with the pistillate heads located below and in the axils of leaves.[6] This bloom period is from June through November.
The pistillate heads yield fruits which are achenes located within oval-shaped greenish-brown burs about half a centimeter long. The burs are hairy and sometimes spiny. The plant reproduces by seed and by sprouting up from a creeping rhizome-like root system.[11]
Ambrosia psilostachya is a host plant for the caterpillars of Bucculatrix transversata,[12] Cosmopterix opulenta, Exaeretia gracilis, Gnorimoschema saphirinella,[13] Schinia sexplagiata; the beetles Zygogramma disrupta, Zygogramma suturalis;[14] and the grasshopper Spharagemon collare.[15]
This plant had a number of medicinal uses among several different Native American tribes, including the Cheyenne, Kumeyaay (Diegueno), and Kiowa people.[16]
Ambrosia psilostachya contains a group of phytochemicals called psilostachyins.[17]
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: CS1 maint: url-status (link) Ambrosia psilostachya is a species of ragweed known by the common names Cuman ragweed and perennial ragweed, and western ragweed.