Gray and Green Rabbitbrush......Photo from south-central Oregon
Western Wormwood Artemisia ludoviciana - Upright, aromatic herbaceous (perhaps somewhat woody at the base, so included here) plant with numerous flower heads clustered close to the upper part of the main stem. The flower heads are discoid, with 6-45 yellowish disk flowers, depending on the variety. Leaves are entire to deeply parted or divided. Plants are somewhat silvery haired.
Scabland Sagebrush, Stiff Sagebrush Artemisia rigida - Woody shrubs with a rounded form to 40 cm high. The leaves are deeply 3-5 cleft and deciduous. The flower heads are sessile in the axils of the leaves which are longer than the heads.
Big Sagebrush, Tall Sagebrush: Artemisia tridentata ssp. tridentata (Synonym: Artemisia tridentata var. tridentata) - Woody shrub, freely branched above, from 4-30 dm tall. Leaves gray, crowdedn narrowly cuneate with 3 rounded teeth or lobes on the blunt tip. Flower heads loosely spread out along the tips of the branches. The flower heads are soley discoid with 3-8 flowers per head.
Green Rabbitbrush, Lanceleaf Rabbitbrush, Lanceleaf Green Rabbitbrush, Sticky-leaf Rabbitbrush, Yellow Rabbitbrush: Chrysothamnus viscidiflorus ssp. lanceolatus (Synonyms: Chrysothamnus viscidiflorus var. lanceolatus, Ericameria viscidiflora ssp. lanceolata) - Freely branched shrubs to 12 dm tall. Leaves are linear to linear-oblong, green, lacking hairs. The yellow flower heads form cymose clusters at the branch tips. The flower heads are discoid and narrow.
Sticky-flowered Rabbitbrush, Sticky-leaf Rabbitbrush, Sticky Yellow Rabbitbrush, Yellow Rabbitbrush: Chrysothamnus viscidiflorus ssp. viscidiflorus (Synonyms: Chrysothamnus viscidiflorus ssp. pumilus, Chrysothamnus viscidiflorus ssp. stenophyllus, Chrysothamnus viscidiflorus var. pumilus, Chrysothamnus viscidiflorus var. stenophyllus, Chrysothamnus viscidiflorus var. viscidiflorus, Ericameria viscidiflora ssp viscidiflora, Ericameria viscidiflrus var. stenophylla) - Seen in the vicinity of the Umatilla Wildlife Refuge.
Heath Goldenrod, Rabbitbush, Rabbitbrush Goldenweed: Ericameria bloomeri (Synonyms: Haplopappus bloomeri, Haplopappus bloomeri var. angustatus, Happlopappus bloomeri var. bloomeri, Haplopapppus bloomeri var. sonnei) - I don't believe this is in the Columbia River Gorge proper, but it can be found north of the Columbia River near BZ Corners, WA in the White Salmon River drainage. It perhaps can be found closer to the river than that, and perhaps at different locations.
Gray Rabbitbrush, Rubber Rabbitbrush: Ericameria nauseosa var. speciosa (Synonyms: Chrysothamnus nauseosus ssp. albicaulis, Chrysothamnus nauseosus var. albicaulis, Chrysothamnus nauseosus ssp. speciosus, Chrysothamnus nauseosus var. speciosus, Ericameria nauseosa ssp. nauseosa var. speciosa) - Low to mostly tall shrubs covered with soft, gray, felt-like and dense hairs. Leaves linear. Yellow flower heads in cymose clusters of about 5 flowers each. Flower heads are discoid and narrow. Plants to 2 meters tall.
Columbian Goldenbush, Columbia Goldenweed, Columbian Heath Goldenrod: Ericameria resinosa (Synonym: Haplopappus resinosus) - Shrubs to 60 cm in height, often found growing from cracks in basalt cliffs. The stems are brittle and resinous, and the leaves are glabrous and resinous. The flower heads are narrow with 3-7 pale yellow or whitish ray flowers.
Broom Snakeweed, Kindlingweed, Match Brush, Matchweed: Gutierrezia sarothrae - Small shrub to subshrub with many erect stems. The stems are very thin and brittle. The leaves are linear. The inflorescence is flat-topped. Flower heads have 3-8 yellow rays and 3-8 disk flowers.
Gray Horsebrush, Spineless Horsebrush: Tetradymia canescens (Synonym: Tetradymia inermis)