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Delphinium oreganum

Willamette Valley larkspur

newton's larkspur, Ozark larkspur

Stems

40-70 cm.

40-90 cm;

base often reddish, puberulent.

Leaves

blade round to pentagonal, 4-7 × 5-15 cm, nearly glabrous; ultimate lobes 3-7, width 8-20 mm (basal), 5-15 mm (cauline), widest at middle or in proximal 1/2.

Inflorescences

8-20(-40)-flowered, as wide as long or nearly so;

pedicel 1-4(-6) cm, pubescent;

bracteoles 6-15 mm from flowers, green, linear, 1.5-5 mm, puberulent.

Flowers

sepals blue or bluish purple, spurs 10-13 mm;

lower petal blades 4.5-6.5 mm.

sepals dark to light blue, rarely white, glabrous, lateral sepals spreading, 12-14 × 6-7 mm, spurs straight to decurved, within 30° of horizontal, 10-15 mm;

lower petal blades slightly elevated, ± exposing stamens, 4-5 mm, clefts 2-3 mm;

hairs mostly centered near base of cleft, yellow.

Fruits

8-12 mm, 3-3.5 times longer than wide, nearly glabrous.

Seeds

unwinged;

surface of each seed coat cell with swollen, blunt, hairlike structures, barely visible at 20x, otherwise smooth.

2n

= 16.

Delphinium nuttallii subsp. nuttallii

Delphinium newtonianum

Phenology Flowering late spring–early summer. Flowering early summer.
Habitat Rock outcrops, rocky meadows Slopes in deciduous forest
Elevation 20-300 m (100-1000 ft) 500-700 m (1600-2300 ft)
Distribution
from FNA
OR; WA
from FNA
AR
[BONAP county map]
Discussion

No cases of hybridization are known. Delphinium newtonianum often occurs in mixed populations with D. tricorne. It normally does not begin flowering until 4-6 weeks after D. tricorne has finished.

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

Source FNA vol. 3. FNA vol. 3.
Parent taxa Ranunculaceae > Delphinium > sect. Diedropetala > subsect. Grumosa > Delphinium nuttallii Ranunculaceae > Delphinium > sect. Diedropetala > subsect. Grumosa
Sibling taxa
D. nuttallii subsp. nuttallii, D. nuttallii subsp. ochroleucum
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. 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. 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 unknown D. M. Moore: Rhodora 41: 196. (1939)
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