Flora of North America species comparison

Subspecies 4 (4 in the flora).

Artemisia tridentata has undergone considerable taxonomic revision in the past century and circumscription of subspecies remains a topic of considerable controversy. Workers in the field should be aware of the morphologic variation within the subspecies across the range of the species (i.e., approximately from the Sierra Nevada in the west to the plains of the Rocky Mountains in the east). Because rangeland managers and conservationists can often identify local morphologic and chemical races based on grazing or habitat preferences of wildlife and domestic animals, some impetus exists to further subdivide the subspecies within A. tridentata at the varietal level. This treatment of the species complex remains conservative in light of the need for further study. As to chemical differences among the subspecies, aroma is often used to distinguish subspecies in the field. Volatile resins in the plants are strongly aromatic and, when crushed, leaves have very distinctive (although not easily described) aromas.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Artemisia nova is the common low-growing dark-green (“black”) sagebrush of desert valleys or south-southwest-facing slopes. It is prized by sheep ranchers as forage in areas where little else is available for grazing. It is conspicuous by its low growth habit, dark green foliage, and, in late season, by its pale orange to light brown flowering branches that rise beyond the vegetative growth. Often confused in herbarium collections with A. arbuscula, A. nova is easily distinguished by the entire leaves of the flowering stems, pedunculate heads, narrowly turbinate involucres, and often straw-colored, glabrous or sparsely hairy phyllaries.

(Discussion copyrighted by Flora of North America; reprinted with permission.)