Swale Desert-parsley, Swale Desert Parsley, Wyeth Biscuitroot, Streambank Desert-parsley, Streambank Desert Parsley
Synonyms: Cogswellia ambigua, Peucedanum ambiguum
The photo above shows swale desert parsley
as seen from a parking area at the trailhead for Hog Lake, a BLM site east of Sprague, WA..........April 27, 2006. Note that this species has large stem leaves and that the petioles are broad and somewhat leaf-like.
The photo at right shows the underside of an umbellet of swale desert parsely as seen from a parking area at the trailhead for Hog Lake, a BLM site east of Sprague, WA.........April 27, 2006. Note the lack of bracts at the base of the umbellet.
Also known as lacy lomatium, swale desert parsley is a low perennial
wildflower with simple to branched stems from 10-80 cm long. The edible root
ranges from short and globose to long and thin. The herbage of the stems and
leaves is both glabrous and glaucous. The leaves are either both basal and on
the stems, or often entirely on the stems. Individual leaves are ternately to
ternate-pinnately twice to several times dissected into narrow, linear segments.
The larger segments are 1-8 cm long and up to 5 mm wide while the smaller segments
are only 1-2 mm long. The long petioles are sheathed their entire length.
The inflorescence is an umbel of 8-17 rays of unequal length
with each ray from 3-10 cm long in fruit. No bracts are found at the base of
the umbel or umbellets. The pedicels are 4-13 mm long and the flowers are yellowish.
The glabrous fruits are narrowly oblong, 5.5-12 mm long and 1.5-3.5 mm wide.
The lateral wings of the fruits are less than half as wide as the body of the
Swale desert parsley is found on open, dry, stony slopes, flats and swales
from the scablands, valleys and foothills up to middle elevations in the mountains.
It may be found to elevations as high as 2700 meters.
Swale desert parsley may be found east of the Cascade Mts. from southern British
Columbia across central and eastern Washington to northern and northeastern
Oregon and east to Montana and at the southern extent of its range across the
Snake River Plains of Idaho to northwestern Wyoming and the Wasatch Mts. of
The photo above shows a close-up of the greatly expanded base of the petiole of a stem leaf of swale desert parsley as seen in lithosol soils along the old highway near Fishtrap Lake to the west of Spokane, WA........April 28, 2007. Note the heavily pollen-laden bee at lower left.
The photo above shows swale desert parsley as seen in lithosol soils along the old highway near Fishtrap Lake to the west of Spokane, WA..........April 28, 2007.
A close-up at left of the stem of swale desert parsley showing the stem leaves with enlarged petiole bases, the dissected leaf blades and inflorescence. Photographed along Rock Creek at the Escure Ranch (BLM), eastern Adams County, WA.........May 14, 2011. The photo at right shows swale desert parsley blooming along the Headquarters Trail, Turnbull National Wildlife Refuge......May 8, 2019.
Additional photos of swale desert parsley as seen in lithosol soils along the old Sprague Highway several miles west of Fishtrap Lake or about one mile west of Miller Ranch Road.......April 28, 2007.
Additional photos of swale desert parsley as seen in lithosol soils along the old Sprague Highway several miles west of Fishtrap Lake or about one mile west of Miller Ranch Road.......April 28, 2014.
Swale desert parsley as seen along the Lookout Mountain Trail, Okanogan National Forest.......June 10, 2011.