Ambrosia ilicifolia
Encyclopedia
Ambrosia ilicifolia 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 names Hollyleaf Burr Ragweed and Hollyleaf Bursage.

It is native to the deserts and mountains of western Arizona
Arizona
Arizona ; is a state located in the southwestern region of the United States. It is also part of the western United States and the mountain west. The capital and largest city is Phoenix...

 and adjacent southeastern California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

 and Baja California
Baja California
Baja California officially Estado Libre y Soberano de Baja California is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is both the northernmost and westernmost state of Mexico. Before becoming a state in 1953, the area was known as the North...

, where it grows in dry washes, scrub, and other local habitat. This is a small, matted shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...

 under a meter in height. Its stiff, straight branches are green, glandular, and leafy when young, and light gray and leafless when older. The holly-like leaves are leathery but brittle, oval-shaped to rounded, and edged with spine-tipped teeth. They are green, veiny, and sticky with resin. 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...

 holds several spiny staminate
Stamen
The stamen is the pollen producing reproductive organ of a flower...

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

 next to larger 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) heads. Each pistillate head produces usually two fruits, which are yellow-brown burrs
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...

nearly 2 centimeters wide. Each burr is rounded, sticky, and covered in hooked spines.

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