Coyote brush (Baccharis pilularis). The leaf shape and venation separate this species from broom baccharis (B. sarothroides), although I have observed individuals resembling the latter species on Owens Peak. Hybridization may occur between these 2 species.

Coyote brush (Baccharis pilularis) is very drought resistant native shrub and a prolific seed producer. The species is dioecious with separate unisexual male and female plants in the population. The term bisexual is not appropriate when discussing Baccharis species. Silky-haired seeds are only produced on the female shrubs and there are often so many that the shrubs appear covered in a white, fuzzy mass. In fact, early Californians reportedly referred to these shrubs as "fuzzy-wuzzy."

A fuzzy female coyote brush covered with silky-haired seeds near the Science Building.

The prolific production of airborne silky-haired seeds can make female plants undesirable for some landscape situations. In the fall when seeds are released, the slightest gust of wind can fill the air with miniature seed parachutes. The seeds land on your clothing, hair, and screens. They can also block the skimming action on swimming pools. In fact, I once had a swimming pool in my yard with willow and other messy trees that I love. I finally had a demolition man punch holes in the bottom with a jack hammer and fill the pool with top soil and manure. I'm sure my neighbors thought I was insane!

To really appreciate this shrub, you really need to see its tiny flowers on separate male and female plants. The flowers are produced in dense clusters (heads) called capitula (sing. capitulum).

The above image shows a single amber twig ant collected 1 November 2013 on the stem of a flowering female shrub that keys out to chaparral broom B. sarothroides, although it is probably a fall-blooming B. pilularis. All of the nearby shrubs are coyote brush (Baccharis pilularis), and I have often seen scattered shrubs in B. pilularis populations that more closely resemble chaparral broom (B. sarothroides), particularly in the fall-blooming months. Other ants in the area (Tapinoma sessile and Formica aerata) appeared interested in the numerous flowering heads of seed-bearing achenes on female coyote brush.

The above ant is Pseudomyrmex apache. Its range includes the southwestern United States and Mexico. It is also reported from nearby Laguna Beach. P. pallidus is very similar and is known from the southern U.S. and Mexico, south to Costa Rica. The identification of P. apache was confirmed by authorities Dr. Alex Wild, University of Illinois and Phil Ward, University of Calif, Davis (personal communication, 4 November 2013). This species belongs to the same genus as the acacia ant (P. ferrugineus) of Costa Rica that lives symbiotically with swollen-thorn acacia trees.

Pseudomyrmex apache typically nests inside cavities of dead branches and abandoned galleries hollowed-out by beetles. It is found throughout most of California except the mountains and extreme north. It occurs in chaparral, oak woodland, mixed (oak-pine-douglas fir) forest, coastal sage scrub, and desert riparian sites. Nests have been collected in dead branches of Arctostaphylos, Baccharis, Quercus and Umbellularia. There are also records from a Fraxinus gall and a Pinus attenuata cone. Workers appear to be "generalist scavengers." My specimen was discovered in the coastal sage scrub of northern San Diego County (north side of Owens Peak) on a flowering Baccharis pilularis that resembled B. sarothroides. Dead branches of this common shrub often have hollow stems; however, I have yet to find the active nest of this remarkable ant species.

The following malformation (swelling) on the stem of coyote brush (Baccharis pilularis) is caused by the rust fungus Puccinia. Masses of orange spores have broken through the stem in pustules (uredinia = uredia). The single-celled spores are called uredospores (urediniospores): Dikaryotic, auto-infecting vegetative spores. The native ant Tapinoma sessile was presumably interested in the spores.