''Ambrosia chamissonis'' is a species of

ragweed 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,North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

from

Alaska Alaska ( ) is a non-contiguous U.S. state on the northwest extremity of North America. Part of the Western United States region, it is one of the two non-contiguous U.S. states, alongside Hawaii. Alaska is also considered to be the north ...

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

, where it is a resident of beaches and other sandy coastal habitats.Flora of North America Vol. 21 Page 16 Ambrosia chamissonis (Lessing) Greene, Man. Bot. San Francisco. 188. 1894.
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Description

''Ambrosia chamissonis'' is a large, sprawling perennial herb exceeding in maximum width. The stems are roughly or softly hairy and longitudinally ridged. The plentiful leaves are a few centimeters long, woolly and silver-green, and variable in shape. The plant is

monoecious Monoecy (; adj. monoecious ) is a sexual system in seed plants where separate male and female cones or flowers are present on the same plant. It is a monomorphic sexual system comparable with gynomonoecy, andromonoecy and trimonoecy, and contras ...

, with male and female flowers on each individual. Staminate (male)

flower heads A pseudanthium (; : pseudanthia) 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, composite flowers ...

containing many pale colored florets occur at the tip of the

inflorescence In botany, an inflorescence is a group or cluster of flowers arranged on a plant's Plant stem, stem that is composed of a main branch or a system of branches. An inflorescence is categorized on the basis of the arrangement of flowers on a mai ...

, with

pistillate Gynoecium (; ; : gynoecia) is most commonly used as a collective term for the parts of a flower that produce ovules and ultimately develop into the fruit and seeds. The gynoecium is the innermost whorl of a flower; it consists of (one or more) ...

(female) flower heads clustered below them. Each pistillate head contains a single tiny flower which develops into a fruit. The fruit is a brown bur up to a centimeter wide covered in sharp spines.Jepson Manual Treatment — ''Ambrosia chamissonis''
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References

External links

* chamissonis Plants described in 1831 Flora of Northwestern Mexico Flora of the Southwestern United States Flora of the Northwestern United States Flora of Western Canada Flora of Subarctic America {{Heliantheae-stub