There are two subspecies of Glaucous Willow-herb at the Park. This is subspecies glaberrimum, the most common and the tallest, with branched stems that are as much as 30 inches in height. Most often found above 5,000 feet of elevation, here it grows alongside the Stevens Canyon road.

In this subspecies (glaberrimum) the leaves are more widely separated on the tall stems. The petals are less than half-an-inch long.

Clasping leaves overlap along the 15-inch stems of this more infrequent subspecies (fastigiatum). It grows on cliffs and sometimes along roadsides at middle elevations. The petals are very small.

The petals are very small in fastigiatum. Glaucous Willow-herb is a member of the Evening-Primrose Family (Onagraceae).