Ambrosia confertiflora
Encyclopedia
Ambrosia confertiflora is a species of ragweed
Ragweed
Ragweeds are flowering plants in the genus Ambrosia in the sunflower family Asteraceae. Common names include bitterweeds and bloodweeds....

 known by the common name weakleaf bur ragweed.

It is native to much of northern Mexico and the southwestern United States as far east as Kansas
Kansas
Kansas is a US state located in the Midwestern United States. It is named after the Kansas River which flows through it, which in turn was named after the Kansa Native American tribe, which inhabited the area. The tribe's name is often said to mean "people of the wind" or "people of the south...

 and Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...

. It is a perennial herb reaching heights between 30 centimeters and nearly two meters with bristly, fuzzy green to brown erect stems. The multilobed fuzzy leaves have blades which can be nearly 16 centimeters long and are borne on petiole
Petiole (botany)
In botany, the petiole is the stalk attaching the leaf blade to the stem. The petiole usually has the same internal structure as the stem. Outgrowths appearing on each side of the petiole are called stipules. Leaves lacking a petiole are called sessile, or clasping when they partly surround the...

s with lobed, winglike appendages. As in other ragweeds, the inflorescence
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. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

 has staminate
Stamen
The stamen is the pollen producing reproductive organ of a flower...

 (male) and pistillate
Gynoecium
Gynoecium is most commonly used as a collective term for all carpels in a flower. A carpel is the ovule and seed producing reproductive organ in flowering plants. Carpels are derived from ovule-bearing leaves which evolved to form a closed structure containing the ovules...

 (female) flower heads
Head (botany)
The capitulum is considered the most derived form of inflorescence. Flower heads found outside Asteraceae show lesser degrees of specialization....

. The pistillate heads yield one or two fruits which are burr
Burr (fruit)
A bur is a seed or dry fruit in which the seeds bear hooks or teeth which attach themselves to fur or clothing of passing animals or people. The hooks or teeth can be irritants and very hard to get off of clothing, such as wool or cotton...

s up to half a centimeter long and covered in short spines.

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