Virginia Institute of Marine Science
Annals of the Missouri Botanical Garden
Detailed descriptions, habitat preferences, geographic ranges, and representative specimens are given for the 13 taxa of the Acacia coulteri group from Mexico, Central America, and the southwestern United States. These species form a distinct group within Acacia series Vulgares, lacking prickles and usually having persistent stipules. A principal components analysis (PCA) of vegetative and floral features shows that the specimens examined form discrete units in plots of the first three principal components. The groups established by PCA mostly coincide with previously described species. The taxa within this group are phenetically similar, sharing many morphological features. These data also suggest that there is occasional gene flow between species, but that hybrids are not common. About half the species have restricted ranges (A. compacta, A. dolichostachya, A. durangensis, A. millefolia, A. russelliana, A. sericea, and A. willardiana), but the remainder are wide-ranging, either from Oaxaca and Puebla north into central and northern Mexico (A. acatlensis, A. coulteri, A. mammifera, and A. salazari), or south into Central America (A. centralis and A. usumacintensis).
Jawad, Jennifer T.; ,Seigler, David S.; and Ebinger, John E., A Systematic Treatment of Acacia coulteri (Fabaceae, Mimosoideae) and Similar Species in the New World (2000). Annals of the Missouri Botanical Garden, 87, 528-548.