File:Desert bitterbrush, Purshia glandulosa leaves (left) with Purshia tridentata leaves (right) (16835202736).jpg

desert bitterbrush, Purshia glandulosa leaves (left) with Purshia tridentata leaves (right), Carson Range, elevation 1555 m (5105 ft). This is a recently discovered northward range extension for Purshia glandulosa, which otherwise appears limited to the Mojave Desert and adjacent Great Basin transition zone, southward to Baja California. It was only noticed here after seeing it come into flower about 2 weeks later than the Purshia tridentata with which it grows. The flowering times are apparently different enough at this location to prevent gene flow, and no hybrids could be found after extensive searches. The population covers several acres and seems quite healthy. The habitat is shallow sandy and rocky granitic soil on mostly southward exposures, fairly typical in the northern portion of its known range.

Based on ongoing observations, the higher-elevation reports of Purshia glandulosa (Intermountain Flora etc.) appear instead to be a prostrate and more glandular (and unnamed) variant of Purshia tridentata, with which it shares the flatter primary leaves with only narrowly inrolled margins, and prominent white pubescence on at least the undersides, and with which it clearly intergrades.