Ambrosia acanthicarpa
The most common Ambrosia in southern New Mexico. Similar to A. artemisiifolia but with longer spines on the pistillate pseudanthia and black ribs on the phyllaries of the staminate pseudanthia and usually on the tips of the leaves as well.
Staminate pseudanthia, Burro Spring Canyon on the west side of the Big Burro Mountains, 22 Sep 2007.
A pistillate pseudanthium in Burro Spring Canyon, 22 Sep 2007.
A lower cauline leaf on the west side of the Big Burro Mountains, 22 Sep 2007.
Pubescence of the stem and petiole, Burro Spring Canyon, 22 Sep 2007.