Burke: Delphinium trolliifolium vs. Delphinium occidentale

	Delphinium trolliifolium	Delphinium occidentale
	cow-poison, poison larkspur	western larkspur
Habit	Stout perennial from short, thick rhizomes, the several erect stems 7-15 dm. tall, simple below the inflorescence, hollow, glabrous to sparsely hairy.
Leaves	Leaves numerous, evenly spaced and gradually reduced upward, the blades of the lower ones 10-20 cm. broad, tri-lobed nearly to the base, the 2 lateral lobes deeply divided into 2-3 segments, the segments broadly wedge-shaped and 2-3 times deeply toothed.
Flowers	Inflorescence elongate and loose, the raceme usually simple, pubescent with spreading, yellowish hairs, leafy-bracteate below; pedicels considerably exceeding the sepal spur, spreading; sepals 5, deep blue, oblong-lanceolate and pointed, 18-25 mm. long, the spur straight, about equal to the blade of the upper sepal; petals 4, small, the lower pair colored as the sepals, the upper pair white; stamens numerous; pistils 3.
Fruits	Follicles glabrous, about 15 mm. long.

	Delphinium trolliifolium	Delphinium occidentale
Flowering time	April-May	June-August
Habitat	Moist, shady woods at low to middle elevations.	Montane meadows and thickets, bogs, and streamsides.
Distribution	Occurring west of the Cascades crest and in the Columbia River Gorge in Washington; Washington south to California. [WildflowerSearch map] [BONAP county map]	Occurring east of the Cascades crest in southeastern Washington; Washington to northeastern Nevada, east to Montana, Wyoming, Colorado, and Utah. [BONAP county map]
Origin	Native	Native
Conservation status	Not of concern	Not of concern
Sibling taxa	D. ajacis, D. basalticum, D. ×burkei, D. depauperatum, D. distichum, D. glareosum, D. glaucum, D. leucophaeum, D. lineapetalum, D. menziesii, D. multiplex, D. nuttallianum, D. nuttallii, D. occidentale, D. stachydeum, D. sutherlandii, D. viridescens, D. xantholeucum	D. ajacis, D. basalticum, D. ×burkei, D. depauperatum, D. distichum, D. glareosum, D. glaucum, D. leucophaeum, D. lineapetalum, D. menziesii, D. multiplex, D. nuttallianum, D. nuttallii, D. stachydeum, D. sutherlandii, D. trolliifolium, D. viridescens, D. xantholeucum
Subordinate taxa		D. occidentale var. occidentale
Web links	Local floras: CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: OR, WA Local Web sites: Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Delphinium occidentale

cow-poison, poison larkspur

western larkspur

Habit

Stout perennial from short, thick rhizomes, the several erect stems 7-15 dm. tall, simple below the inflorescence, hollow, glabrous to sparsely hairy.

Leaves

Leaves numerous, evenly spaced and gradually reduced upward, the blades of the lower ones 10-20 cm. broad, tri-lobed nearly to the base, the 2 lateral lobes deeply divided into 2-3 segments, the segments broadly wedge-shaped and 2-3 times deeply toothed.

Flowers

Inflorescence elongate and loose, the raceme usually simple, pubescent with spreading, yellowish hairs, leafy-bracteate below;

pedicels considerably exceeding the sepal spur, spreading;

sepals 5, deep blue, oblong-lanceolate and pointed, 18-25 mm. long, the spur straight, about equal to the blade of the upper sepal;

petals 4, small, the lower pair colored as the sepals, the upper pair white;

stamens numerous;

pistils 3.

Fruits

Follicles glabrous, about 15 mm. long.