Rabbitbrush, Chrysothamnus sp., likely C. viscidiflorus.  See-twisted-leaves. In asteraceae-sunflower. Photo from RMNP 09062016.Rabbitbrush, Chrysothamnus sp., Asteraceae (sunflower) -rmnp-09062016

 

CO plant database search returns 5 species- all native. Species characteristics are copied below:

Chrysothamnus depressus   DWARF RABBITBRUSH

“heads 0.5 inch high; phyllaries (bracts – small leaf-like structures – below composite heads) strongly keeled (with a prominent dorsal rib), in very conspicuous vertical ranks; leaves oblanceolate (lance-shaped with the widest part at the tip) to spatulate (oblong with a narrow base); rarely over 12 inches tall.”

Chrysothamnus linifolius  FLAX-LEAVED RABBITBRUSH

“over 3 feet high, relatiely unbranched plants; leaves 0.25 inch wide or more, elongate and hardly twisted.”

Chrysothamnus nauseosus COMMON RABBITBRUSH

“irregular globe shape with woody based stems with herbaceous tips. Pappus (appendages at the tip of the ovary) with numerous capillary (thread-like) bristles; phyllaries (flower head bracts – small leaf-like structures) imbricated (overlapping, like shingles), in vertical rows, obtuse (blunt) to acute (pointed); twigs covered with a feltlike tomentum (wooly hairs). 2-6 feet.”

Chrysothamnus parryi  MOUNTAIN RABBITBRUSH

“heads in leafy spikelike or facemose clusters, sometimes branching to form panicles; outer phyllaries (bracts – reduced leaf-like structures – that subtend a flower head in sunflowers) often prolonged into slender herbaceous tips or appendages. to 12 inches.”

Chrysothamnus viscidiflorus  DWARF RABBITBRUSH

“leaves less than 5 mm wide, typically twisted. to 10 inches”

The pictures below are from the Coal Creek trail 08312017.

Thinking it is common rabbit brush. Chrysothamnus nauseosus.

Rabbitbrush, Chrysothamnus sp., Asteraceae (sunflower) Coal creek trail, 08312017Rabbitbrush, Chrysothamnus sp., Asteraceae (sunflower) Coal creek trail, 08312017