• Knightia eocaena mass mortality

    Fossil Butte

    National Monument Wyoming

Grasses

Tufted twinpod in bloom

Tufted twinpod.

NPS photo by Clay Kyte

The Grass/Forb type is dominated by Sandberg bluegrass (P. sandbergii), but Indian ricegrass (Achnatherum hymenoides) and wheatgrasses are also present. Common forbs include stemless goldenweed (Stenotus acaulis var. acaulis), Hood's phlox (Phlox hoodii), and starveling milkvetch (Astragalus jejenus). This type thrives on drier sites with shallow soil, such as rocky ridges. The Grass/Forb type also exists where fire has burned shrubby vegetation types. Rock outcrops and barren windswept ridges were mapped as the Barren type. Some areas are nearly devoid of vegetation; others support widely-spaced cushion plants, grasses, and forbs such as tufted twinpod (Physaria condensata).

Did You Know?

Fossil Butte from a distance

Fossil Butte National Monument preserves only 1% of the Fossil Lake deposits, the smallest of three ancient lakes that make up the famous Green River Formation.