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Delphinium basalticum

basalt larkspur, basaltic larkspur, Columbia Gorge larkspur

Geyer's larkspur, poisonweed

Stems

20-50(-65) cm;

base often reddish, puberulent.

(15-)30-60(-80) cm;

base usually reddish, puberulent.

Leaves

blade round, 2-6 × 5-9 cm, not succulent, nearly glabrous; ultimate lobes 5-19, width 3-15 mm (basal), 1-12 mm (cauline).

blade light green, ± round, 1-5 × 1-6 cm, densely pubescent; ultimate lobes 7-20, width 2-5 mm (basal), 2-4 mm (cauline), apex gradually tapering to point;

veins obscure.

Inflorescences

(2-)6-16(-26)-flowered;

pedicel 2-7 cm, nearly glabrous;

bracteoles 4-12 mm from flowers, green, linear, 3-7 mm, nearly glabrous.

6-30(-60)-flowered, ± open, cylindric;

pedicel ascending to spreading, 1-3(-4) cm, puberulent;

bracteoles 1-3 mm from flowers, green, lanceolate, 3-6 mm, puberulent.

Flowers

sepals dark blue, nearly glabrous, lateral sepals spreading, 15-21 × 7-10 mm, spur straight to decurved, ascending 30-45° above horizontal, 14-18 mm;

lower petal blades slightly elevated, ± exposing stamens, 7-9 mm, cleft 4-5 mm;

hairs centered, mostly on inner lobes above base of cleft, yellow to white.

sepals bright blue, puberulent, lateral sepals spreading, 10-18 × 4-8 mm, spurs straight to slightly downcurved, ascending 0-30°, 11-16 mm;

lower petal blades slightly elevated, ± exposing stamens, 4-8 mm, clefts 0.5-2 mm;

hairs centered, densest on inner lobes near base of cleft, white to light yellow.

Fruits

12-17 mm, 3.5-4 times longer than wide, glabrous.

11-15 mm, 3-3.5 times longer than wide, sparse puberulent.

Seeds

± wing-margined;

seed coat cells with surfaces smooth.

unwinged;

seed coat cells with margins straight, surfaces ± roughened.

2n

= 16.

Delphinium basalticum

Delphinium geyeri

Phenology Flowering spring (-early summer). Flowering late spring–early summer.
Habitat Basaltic cliff faces, n and e slopes at base of cliffs Grasslands or Artemisia-Cercocarpus scrub
Elevation 200-500 m (700-1600 ft) 1400-3000 m (4600-9800 ft)
Distribution
from FNA
OR; WA
[BONAP county map]
from FNA
CO; MT; NE; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Hybrids between Delphinium basalticum and D. trolliifolium are known.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Apparently closely related to Delphinium stachydeum, D. geyeri is generally smaller, earlier flowering, with more finely dissected leaves and a more eastern geographic distribution.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 3. FNA vol. 3.
Parent taxa Ranunculaceae > Delphinium > sect. Diedropetala > subsect. Bicoloria Ranunculaceae > Delphinium > sect. Diedropetala > subsect. Wislizenana
Sibling taxa
D. alabamicum, D. alpestre, D. andersonii, D. andesicola, D. antoninum, D. bakeri, D. barbeyi, D. bicolor, D. brachycentrum, D. californicum, D. cardinale, D. carolinianum, D. decorum, D. depauperatum, D. distichum, D. elatum, D. exaltatum, D. geraniifolium, D. geyeri, D. glareosum, D. glaucescens, D. glaucum, D. gracilentum, D. gypsophilum, D. hansenii, D. hesperium, D. hutchinsoniae, D. inopinum, D. lineapetalum, D. luteum, D. madrense, D. menziesii, D. multiplex, D. newtonianum, D. novomexicanum, D. nudicaule, D. nuttallianum, D. nuttallii, D. parishii, D. parryi, D. patens, D. polycladon, D. purpusii, D. ramosum, D. recurvatum, D. robustum, D. sapellonis, D. scaposum, D. scopulorum, D. stachydeum, D. sutherlandii, D. treleasei, D. tricorne, D. trolliifolium, D. uliginosum, D. umbraculorum, D. variegatum, D. viridescens, D. wootonii, D. xantholeucum
D. alabamicum, D. alpestre, D. andersonii, D. andesicola, D. antoninum, D. bakeri, D. barbeyi, D. basalticum, D. bicolor, D. brachycentrum, D. californicum, D. cardinale, D. carolinianum, D. decorum, D. depauperatum, D. distichum, D. elatum, D. exaltatum, D. geraniifolium, D. glareosum, D. glaucescens, D. glaucum, D. gracilentum, D. gypsophilum, D. hansenii, D. hesperium, D. hutchinsoniae, D. inopinum, D. lineapetalum, D. luteum, D. madrense, D. menziesii, D. multiplex, D. newtonianum, D. novomexicanum, D. nudicaule, D. nuttallianum, D. nuttallii, D. parishii, D. parryi, D. patens, D. polycladon, D. purpusii, D. ramosum, D. recurvatum, D. robustum, D. sapellonis, D. scaposum, D. scopulorum, D. stachydeum, D. sutherlandii, D. treleasei, D. tricorne, D. trolliifolium, D. uliginosum, D. umbraculorum, D. variegatum, D. viridescens, D. wootonii, D. xantholeucum
Name authority M. J. Warnock: Phytologia 78: 91. (1995) Greene: Erythea 2: 189. (1894)
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