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silvery lupine

bicolor lupine, field lupine, Lindley's annual lupine, Lindley's lupine, lupine, miniature lupine, Montana lupine, small-flower lupine, two-color lupine, two-colour lupine

Habit Herbs, perennial, 1–15 dm, green and glabrous or silvery-hairy; from superficial or shallowly buried root crown. Herbs, annual, 0.5–4 dm, pubescent.
Stems

erect or ascending, green or purplish, clustered, branched or unbranched.

ascending or erect, branched or unbranched.

Leaves

basal and/or cauline;

stipules 2–12 mm;

petiole 1–15 cm;

leaflets (5 or)6–10, blades 10–60 × 4–10 mm, abaxial surface hairy, adaxial surface glabrous or hairy (but not strigose).

cauline;

petiole 1–7 cm;

leaflets 5–8, blades 10–40 × 1–5 mm, adaxial surface glabrous or sparsely pubescent.

Racemes

loose, 5–16(–25) cm;

flowers whorled or not.

4–20 cm;

flowers usually in fewer than 5 whorls, sometimes spirally arranged.

Peduncles

(1–)4–25(–30) cm;

bracts usually deciduous, 3–4 mm.

3–10 cm;

bracts deciduous, 4–6 mm.

Pedicels

(1–)2–5(–7) mm.

1–3.5 mm.

Flowers

5–15 mm;

calyx 4–8 mm, bulge or spur 0–3 mm (may be variable on plant), abaxial lobe entire or 3-toothed, adaxial lobe entire or 2-toothed;

corolla usually blue, sometimes purple, violet, pink, lilac, or white, banner patch yellowish to whitish, blue, brown, or absent, banner not much reflexed-recurved beyond midpoint, this less than 3 mm proximal to apex, banner glabrous or pubescent abaxially, wings glabrous, lower keel margins glabrous, upper margins ciliate.

4–10 mm;

calyx abaxial lobe entire, 4–6 mm, adaxial lobe deeply cleft, 2–4 mm;

corolla usually blue, rarely light blue, pink, or white, banner spot white, becoming magenta, upper keel margins usually ciliate near apex, rarely glabrous, sometimes blunt, banner longer than wide.

Legumes

(1–)2–3 cm, hairy or silky.

1–3 × 0.3–0.6 cm, pubescent.

Cotyledons

deciduous, petiolate.

deciduous, petiolate.

Seeds

(2 or)3–5(or 6), tan, brown, or red.

5–8.

2n

= 48.

Lupinus argenteus

Lupinus bicolor

Phenology Flowering late winter–spring (Mar–Jun).
Habitat Open or disturbed areas.
Elevation 0–1600 m. (0–5200 ft.)
Distribution
from USDA
w North America
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; OR; WA; BC; Mexico (Baja California, Baja California Sur, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 14 (14 in the flora).

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

Lupinus bicolor is naturalized in Arizona. The named subspecies and varieties do not conform to consistently recognizable geographical or morphological entities (D. B. Dunn 1955). Vigorous plants with larger flowers may be confused with L. nanus. In California, plants on the Outer North Coast Ranges may persist for two growing seasons. Lupinus bicolor (as L. polycarpus) has been reported from Alabama (A. R. Diamond 2016) and Michigan (E. G. Voss and A. A. Reznicek 2012).

Lupinus micranthus Douglas (1829, not Gussone 1828) is an illegitimate name that pertains here.

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

Key
1. Calyx spur 1–3 mm.
→ 2
2. Flowers in profile appearing open, spur pronounced.
var. heteranthus
2. Flowers in profile appearing closed; spur less pronounced.
→ 3
3. Petioles of proximal cauline leaves 1.5–3 cm.
var. argophyllus
3. Petioles of proximal cauline leaves 3–12 cm.
var. utahensis
1. Calyx bulge 0–1 mm, but not elongated into a spur.
→ 4
4. Leaflets oblanceolate, flat, green, surfaces glabrous or adaxially pubescent; plants of cool, moist mountain meadows, stream banks, lakeshores.
→ 5
5. Corollas pale blue with brown banner patch; pedicels 1–2.5 mm.
var. fulvomaculatus
5. Corollas usually blue with yellow banner spot or none; pedicels usually 3–4 mm.
→ 6
6. Stems unbranched and racemes sol­itary, terminal.
var. rubricaulis
6. Stems branched, giving rise to several racemes.
→ 7
7. Corolla wings (7.5–)8–10 mm.
var. argentatus
7. Corolla wings 5–7.5 mm.
var. parviflorus
4. Leaflets oblanceolate or elliptic-oblanceolate, narrow and often folded, surfaces gray or silver-pubescent; plants of dry open areas, foothills to mountains.
→ 8
8. Stem hairs descending in backward direction or widely spreading.
var. palmeri
8. Stem hairs forwardly appressed.
→ 9
9. Flowers large, (7–)8–15 mm.
→ 10
10. Basal and cauline leaves present at flowering.
var. montigenus
10. Basal leaves absent at flowering.
→ 11
11. Flowers (7–)8–12 mm.
var. argenteus
11. Flowers 12–15 mm.
var. moabensis
9. Flowers small, 5–7(–9) mm.
→ 12
12. Banners densely pubescent.
→ 40g
40g. Lupinus argenteus var. holosericeus.
→ 12
12. Banner glabrous or thinly strigulose abaxially.
→ 13
13. Wings 5.5–7 mm; banner usually thinly strigulose abaxially; Kai­bab Plateau, Arizona, Colorado, Nevada, New Mexico, Utah; elevation 2000–2800 m.
var. hillii
13. Wings 5–6 mm; banner glabrous abaxially; Sierra Nevada, California, adjacent Nevada; elevation 1500–3500 m.
var. meionanthus
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Lupinus Fabaceae > subfam. Faboideae > Lupinus
Sibling taxa
L. adsurgens, L. affinis, L. albicaulis, L. albifrons, L. andersonii, L. angustiflorus, L. antoninus, L. apertus, L. arboreus, L. arbustus, L. arcticus, L. arizonicus, L. benthamii, L. bicolor, L. brevicaulis, L. breweri, L. cervinus, L. chamissonis, L. citrinus, L. concinnus, L. constancei, L. covillei, L. croceus, L. dalesiae, L. diffusus, L. duranii, L. elatus, L. elmeri, L. excubitus, L. flavoculatus, L. formosus, L. fulcratus, L. gracilentus, L. grayi, L. guadalupensis, L. havardii, L. hirsutissimus, L. huachucanus, L. hyacinthinus, L. kingii, L. kuschei, L. lapidicola, L. latifolius, L. lepidus, L. leucophyllus, L. littoralis, L. longifolius, L. ludovicianus, L. luteolus, L. magnificus, L. malacophyllus, L. microcarpus, L. nanus, L. neomexicanus, L. nevadensis, L. nipomensis, L. nootkatensis, L. obtusilobus, L. odoratus, L. onustus, L. oreganus, L. pachylobus, L. padrecrowleyi, L. peirsonii, L. perennis, L. polyphyllus, L. pratensis, L. pusillus, L. rivularis, L. sabineanus, L. sericatus, L. sericeus, L. shockleyi, L. sierrae-blancae, L. sparsiflorus, L. spectabilis, L. stiversii, L. subcarnosus, L. succulentus, L. sulphureus, L. texensis, L. tidestromii, L. tracyi, L. truncatus, L. uncialis, L. villosus, L. westianus
L. adsurgens, L. affinis, L. albicaulis, L. albifrons, L. andersonii, L. angustiflorus, L. antoninus, L. apertus, L. arboreus, L. arbustus, L. arcticus, L. argenteus, L. arizonicus, L. benthamii, L. brevicaulis, L. breweri, L. cervinus, L. chamissonis, L. citrinus, L. concinnus, L. constancei, L. covillei, L. croceus, L. dalesiae, L. diffusus, L. duranii, L. elatus, L. elmeri, L. excubitus, L. flavoculatus, L. formosus, L. fulcratus, L. gracilentus, L. grayi, L. guadalupensis, L. havardii, L. hirsutissimus, L. huachucanus, L. hyacinthinus, L. kingii, L. kuschei, L. lapidicola, L. latifolius, L. lepidus, L. leucophyllus, L. littoralis, L. longifolius, L. ludovicianus, L. luteolus, L. magnificus, L. malacophyllus, L. microcarpus, L. nanus, L. neomexicanus, L. nevadensis, L. nipomensis, L. nootkatensis, L. obtusilobus, L. odoratus, L. onustus, L. oreganus, L. pachylobus, L. padrecrowleyi, L. peirsonii, L. perennis, L. polyphyllus, L. pratensis, L. pusillus, L. rivularis, L. sabineanus, L. sericatus, L. sericeus, L. shockleyi, L. sierrae-blancae, L. sparsiflorus, L. spectabilis, L. stiversii, L. subcarnosus, L. succulentus, L. sulphureus, L. texensis, L. tidestromii, L. tracyi, L. truncatus, L. uncialis, L. villosus, L. westianus
Subordinate taxa
L. argenteus var. argentatus, L. argenteus var. argenteus, L. argenteus var. argophyllus, L. argenteus var. fulvomaculatus, L. argenteus var. heteranthus, L. argenteus var. hillii, L. argenteus var. meionanthus, L. argenteus var. moabensis, L. argenteus var. montigenus, L. argenteus var. palmeri, L. argenteus var. parviflorus, L. argenteus var. rubricaulis, L. argenteus var. utahensis
Synonyms L. bicolor subsp. marginatus, L. bicolor var. micranthus, L. bicolor subsp. microphyllus, L. bicolor var. microphyllus, L. bicolor subsp. pipersmithii, L. bicolor var. pipersmithii, L. bicolor var. rostratus, L. bicolor subsp. tridentatus, L. bicolor var. tridentatus, L. bicolor var. trifidus, L. bicolor subsp. umbellatus, L. bicolor var. umbellatus, L. congdonii, L. polycarpus
Name authority Pursh: Fl. Amer. Sept. 2: 468. (1814) Lindley: Bot. Reg. 13: plate 1109. (1827)
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