''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 and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

from

Alaska Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...

Baja California Baja California (; 'Lower California'), officially the Free and Sovereign State of Baja California ( es, Estado Libre y Soberano de Baja California), is a state in Mexico. It is the northernmost and westernmost of the 32 federal entities of Mex ...

, 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 alongside gynomonoecy, andromonoecy and trimonoecy. Monoecy is conne ...

, with male and female flowers on each individual.

Staminate The stamen (plural ''stamina'' or ''stamens'') is the pollen-producing reproductive organ of a flower. Collectively the stamens form the androecium., p. 10 Morphology and terminology A stamen typically consists of a stalk called the filam ...

(male)

flower heads A pseudanthium (Greek for "false flower"; ) 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, compos ...

containing many pale colored florets occur at the tip of the

inflorescence An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

, with

pistillate Gynoecium (; ) 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) ''pistils'' ...

(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 A bur (also spelled burr) is a seed or dry fruit or infructescence that has hooks or teeth. The main function of the bur is to spread the seeds of the bur plant, often through epizoochory. The hooks of the bur are used to catch on to for exam ...

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