Baccharis are leafy scrubs with whitish or cream-colored disc flowers only in heads. Bracts in whitish papery over lapping rows with male or female heads on separate plants. Leaves are alternate, simple with petioles shorter than leaf blades with one to three principle veins. Eight different species are located in the county per Beauchamp (1986) and the Simpson companion checklist (1995).
Two of eight species found in San Diego County have only the base of the scrub woody with the remaining branches herbaceous, B. brachyphylla and B. douglasii. B. brachphylla or Shortleaf Baccharis are uncommon per Beauchamp, found in upper desert drainages and rocky areas. The few leaves are sessile, short, less than ¾", edges smooth, principle vein 1 and often have scale-like upper leaves. Herbage appears dusty, powdery or is covered with short soft hairs with the remaining species hairless and generally sticky. B. douglasii or Marsh Baccharis are rare, found along Oak Grove and Scissors Crossing streams and drainage channels above 500m per Beauchamp. The branches and leaves are hairless or nearly so, with up to four-inch long lance-shaped leaves, 1-3 principal veins.
The remaining six species have woody branches well above the base with mature leaves greater than ¾" long. B. sarothroides and B. sergilodes have broom-like branches with distinct longitudinal furrows or ridges, almost leafless due to most falling off before the flowers open. B. sarothroides or Broom Baccharis are commonly found in sandy soils, along washes or in disturbed areas. The thick leaves are sessile, linear-oblanceolate; somewhat rolled under with one principle vein. B. sergilodes, Squaw waterweed, or Desert Baccharis is infrequently found in the foothills and deserts along washes and moist areas at 600-1200m elevation (Beauchamp, 1986). The leaves are wider at the top than at the base, barely petioled, with 1 principle vein.
Species persistently leafy and not broom-like are B. salicifolia, B. pilularis and B. emoryi. B. salicifolia (previously glutinosa) or Mule fat is found in riparian woodlands. The leaves are willow-like with the same color on both top and underside. B. pilularis, Coyote bush or Chaparral Broom leaves are ovate, usually 5-9 toothed and dark green in color, principal veins 3. Infrequently found below 200m in Sage Scrub, coastal areas (Beauchamp, 1986). B. emoryi can look somewhat broom-like, occasionally found in foothill and coastal areas along streams and in canyons. Emory's Baccharis leaves are broader at tip, smooth or few-teethed with 3 principle veins.
B. vanessae or Encinitas Baccharis is endangered and found only in San Diego in coastal chaparral. The sessile leaves are linear, entire, with one principle vein. Grows on sandstone.
Beauchamp, Mitchel R., 1986. A Flora of San Diego County, California, Sweetwater River Press, National City, CA
Hickman, James C., Editor, 1993. The Jepson Manual: Higher Plants of California, University of California Press, Berkeley and Los Angeles, CA
Dole, Jim W. and Rose, Betty B., 1996. An Amateurs Botanist's Identification Manual for the Shrubs and Trees of the Southern California Coastal Region and Mountains, Foot-loose Press, North Hills, CA
Dole, Jim W. and Rose, Betty B., 1996. An Amateurs Botanist's Identification Manual for the Shrubs and Trees of the Southern California Deserts, Foot-loose Press, North Hills, CA
Simpson, Michael G., McMillan, Scott C. and Stone, Brenda L., 1995. Checklist of the Vascular Plants of San Diego County, SDSU Herbarium Press, San Diego, CA
Knoll, P. field notes