Figvure 25. — Large s'peaimen of 

 basin hig sagebrush (A. 



Artemisia tridentata Nutt. (big sagebrush^) 



Big sagebrush is a highly polymorphic species with numerous ecotypes and biotypes. 

 Three subspecies {tridentata, wyomingensisj and vaseyana) are generally recognized at 

 the present time (Beetle 1960; Beetle and Young 1965), and will be discussed individu- 

 ally following the general presentation of the species. 



Big sagebrush is composed of aromatic, evergreen shrubs ranging in size from dwarf 

 to tall, arborescent forms up to 4.5 m tall [fig. 25). The lower forms generally have 

 several main stems arising from the base, whereas the tall forms often have a single 

 short trunk. Older branches are covered with a gray to brown or black shredded bark. 

 Younger branches and leaves have a white to gray tomentum which gives tlie plants a 

 silvery cast. 



Typical leaves are narrowly cuneate or oblanceolate and terminate with 3 blunt 

 teeth at their truncate apexes (fig. 26). However, considcral^l e variation occurs, 

 ranging from linear, entire leaves with rounded to acute apexes to broadly cuneate 

 leaves with varying number of teeth or shallow lobes, Tlie leaves also range in size 

 from 2 mm to 2 cm broad and 1 cm to 6.5 cm long. Normally, leaves on vegetative shoots 

 are more characteristic and less variable than those on flower in>' shoots. Also, per- 

 sistent leaves, that is overwintering leaves, are less variable than leaves of the 

 spring growth flush (Winward 1970), which are shed by midsiimiiicr . 



Other common names include common sagebrush and black sav^e. 



26 



