White-rayed wyethia looks like a white-flowered balsamroot. Its leaves are both basal and cauline, with the basal ones elliptic or elliptic-ovate in shape and entire margins. The basal leaves ar about 9 - 35 cm in length and about 3 - 12 cm. The reduced stem leaves are often about 6 - 12 cm long and about 1.5 - 4 cm wide. The stems are stout but lax, and the plant often sprawls across the ground. The stems are about 20 to 80 cm long.
The flower heads are mostly single with a spherical involucre. The bracts are nearly linear and acutely tipped (see photo) with numerous hairs on their margins. The rays are white or pale cream in color, and often dry to a yellowish color so they could be misidentified for Wyethia amplexicaulis from a distance. There are most commonly about 13 rays, but as many as 21 may be found on a head. Individual rays range from 2.5 - 4.5 cm in length.
Wyethia helianthoides is similar in appearance to Wyethia amplexicaulis, which has yellow-rayed flowers. Both seem to hybridize where they overlap.
White-rayed wyethia is found from moist and wet meadows at moderate elevations in the mountains. Its bloomtime is approximately May and June in Oregon.
White-rayed Wyethia is found from central and northeastern Oregon eastward to northern Nevada, Yellowstone Park, and southwestern Montana.
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White-rayed wyethia blooming along FS Rd 16 in Logan Valley, Malheur National Forest......June 5, 2011.
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Early-blooming white-rayed wyethia blooming (left) in moist scablands near the junction of FS Roads #42 and #30 at the southeast corner of Big Summit Prairie, Ochoco National Forest.........April 29, 2016. The photo at right shows white-rayed wyethia blooming at the same location on May 10, 2017..
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White-rayed wyethia blooming on vernally moist scabland habitats along FS Road 4215 about 1.6 miles south of the junction with FS Road 42, Ochoco National Forest...........May 22, 2017.
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White-rayed wyethia blooming at left on vernally moist scabland habitats along FS Road 4215 about 1.6 miles south of the junction with FS Road 42, Ochoco National Forest...........May 9, 2017. The photo at right shows an early-blooming white-rayed wyethia at Bingham Prairie, near the north trailhead for the Twin Pillars Trail, Mill Creek Wilderness......May 18, 2018.
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A meadow of white-rayed wyethia beginning to bloom at left at Horse Prairie along spur road 100 just west of FS Road 4230 near the south boundary of the Ochoco National Forest.......May 19, 2018. The photo at right shows white-rayed wyethia in bloom along FS Road 4215 about 100 meters south of the junction with FS Road 4220, Ochoco National Forest.......May 19, 2018.
Paul Slichter