Burrobrush
Hymenoclea salsola
(Ambrosia salsola)
Sketch made from live specimens at Castle Hot Springs, Yavapai Co., AZ 12 Oct.
1992. a) Staminate (male) flower head, b) solitary, pistalate (female) flower,
c) Seed Bug, Lygaeus kalmi .
FLOWERS: Many short spikes of yellow (due to copious pollen) male and
female flowers. Male heads are several-flowered while the female flower heads
have usu. just one. A series of flattened wings developes from the involucre
and ring each seed (shown enlarged at upper right in illustration).
SHRUB: Medium to large shrubs may be 1
to 3 meters tall, often forming thickets.
LEAVES: Linear, almost thread-like leaves.
RANGE: Common to abundant in washes in the Sonoran Desert, especially
where over grazing by cattle has been practiced.
PAPPUS: (crown at apex of achene) none.
UNARMED.
Many insects are able to get past the chemical defenses that deter grazing cattle. Among these are a leaf beetle, Leptinotarsa lineolata. The black and white banded larva (see image at right) are easily found on the plants by late summer. The adult beetles are green and beige with broken longitudinal stripes.