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golden banner, golden pea, mountain buck-bean, mountain golden-banner, mountain golden-pea, mountain thermopsis

slender goldenbanner, slender thermopsis

Habit Herbs delicate, 2–8(–10) dm, glabrate, appressed-pubescent, or thinly villous. Herbs robust, 3–8 dm, glabrous or sparsely villous.
Stems

slender, erect, solitary or clustered, moderately or few-branched, from woody rootstock or rhizomes;

branches ascending at 20–45º, weakly or moderately zigzag.

slender, erect, solitary or clustered, many-branched, from woody rootstock or rhizomes;

branches spreading at 30–70º, moderately to strongly zigzag.

Leaves

stipules persistent, widely ovate or elliptic, 1.7–4.5 × 0.7–2.5 cm, base oblique to cuneate, apex acuminate or acute;

petiole 1–4 cm;

leaflet blades elliptic or obovate, 3.5–8 × 0.7–3(–5) cm, lateral veins 6–11 pairs, conspicuously net-veined abaxially or not, apex acute or obtuse, sometimes short-mucronate or emarginate, surfaces sparsely appressed-pubescent or glabrous.

stipules persistent, asymmetrically ovate-elliptic, 2.5–3.5 × 1.5–3 cm, base cuneate to cordate, apex acuminate;

petiole 2.5–4(–5) cm;

leaflet blades elliptic to obovate or rhombic, 3–6(–8) × 2–3.2 cm, lateral veins 6–9 pairs, conspicuously net-veined abaxially, apex acute, obtuse, or emarginate, surfaces glabrous.

Racemes

6–25-flowered, 4–25 cm;

flowers in whorls of 2 or 3 or scattered.

7–30-flowered, 12–20(–30) cm;

flowers scattered.

Peduncles

2–8 cm;

bracts semipersistent, narrowly elliptic or elliptic to widely ovate, 6–10 × 2.5–6 mm.

4–9(–11) cm;

bracts semipersistent, ovate, 6–8 × 3–5 mm.

Pedicels

3.5–5 mm, villosulous.

6–16 mm, glabrous or sparsely villous.

Flowers

1.6–2.2 cm;

calyx 9–11 × 5–8 mm at limb, lobes 3–5 mm, shorter than tube;

wings and keel petals asymmetrically oblong-elliptic;

ovary velutinous or densely appressed-pubescent;

ovules 10–16.

2–2.3 cm;

calyx 8–10 × 7–8 mm at limb, lobes 2–3 mm, much shorter than tube;

wing petals elliptic, keel petals asymmetrically oblong-elliptic;

ovary sparsely villous;

ovules 9–14.

Legumes

ascending, straight, 4.5–6.5 × 0.4–0.6 cm, villosulous or appressed-pubescent.

irregularly divergent, straight, 3–6 × 0.4–0.6 cm, inconspicuously pubescent.

Seeds

6–16, brown-black, oblong, 3.5–5 × 2.5–3 mm, beaked.

2–8, tan, oblong, 3–4 × 2 mm, short-beaked.

2n

= 36.

Thermopsis montana

Thermopsis gracilis

Phenology Flowering (Apr–)May–Jun.
Habitat Mesophytic lower mon­tane evergreen forests.
Elevation 100–1200 m. (300–3900 ft.)
Distribution
from USDA
North America
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

The strictly erect fruits distinguish Thermopsis montana from T. gracilis and from the superficially similar T. divaricarpa. Intermediate populations and possible hybrids are discussed under T. divaricarpa by C. J. Chen et al. (1994).

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

Thermopsis gracilis is readily distinguished from the closely allopatric T. californica and T. montana by its divergent fruits, spreading branches, and glabrous to sparsely pubescent foliage. The species is most closely related to T. robusta, which also has divergent fruits but which differs in its very robust habit, densely pilose vestiture, and longer calyx lobes.

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

Key
1. Herbs 2–7 dm, appressed-pubescent to thinly villous; stems solitary or clustered, few-branched, from woody rootstock or rhizomes; leaflet blades not conspicuously net-veined abaxially; floral bracts elliptic to widely ovate.
var. montana
1. Herbs 5–8(–10) dm, glabrate to sparsely appressed-pubescent; stems clustered, several-branched, from woody rootstock; leaflet blades conspicuously net-veined abaxially; floral bracts narrowly elliptic.
var. ovata
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Thermopsis Fabaceae > subfam. Faboideae > Thermopsis
Sibling taxa
T. californica, T. divaricarpa, T. fraxinifolia, T. gracilis, T. macrophylla, T. mollis, T. rhombifolia, T. robusta, T. villosa
T. californica, T. divaricarpa, T. fraxinifolia, T. macrophylla, T. mollis, T. montana, T. rhombifolia, T. robusta, T. villosa
Subordinate taxa
T. montana var. montana, T. montana var. ovata
Synonyms T. rhombifolia var. montana T. macrophylla var. venosa, T. montana var. venosa
Name authority Nuttall in J. Torrey and A. Gray: Fl. N. Amer. 1: 388. (1840) Howell: Erythea 1: 109. 189
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