Hall's Isopyrum as photographed at the Rainy Lake Trailhead, southern boundary of the Hatfield Wilderness (Mt. Hood N.F.).......July 24, 2001.
Hall's Isopyrum is an attractive wildflower suitable for use in the moist, shady garden (Remember that it's poisonous!) It has one to several erect stems rising 30-100 cm high from fleshy roots. The herbage is glaucous and ranges from glabrous to pubescent.
The stems contain 1-3 reduced but compound leaves. The leaves are mostly basal. Individual basal leaves are long petioled with with large, pinnately compound blades, the blade twice to thrice ternate into cuneate, blunt-toothed segments (See photo below.).
The inflorescence consists of terminal or axillary corymbs or umbels of 3-10 flowers. The pedicels range from 2-4 cm long. Individual flowers consist of 5 white to rose sepals, the sepals obovate in shape and from 7-10 mm long. The stamens range from 10 to numerous in number and slender filaments. The pistils number from 2-20.
Hall's Isopyrum may be found in moist woods and along streambanks.
Hall's Isopyrum may be found west of the Cascade Mts. form Lewis and Thurston Counties in Washington south through the Willamette Valley to Marion County in Oregon.
In the Columbia River Gorge it may be found wholly on the Oregon side of the river between the elevations of 1600'-4000' from Larch Mt. east to Mt. Defiance.
The photo above shows one of the large pinnately compound basal leaves of Hall's Isopyrum as photographed at the Rainy Lake Trailhead.......July 24, 2001.