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

pine goldenpea, spreadfruit goldenbanner

Habit Herbs delicate, 2–8(–10) dm, glabrate, appressed-pubescent, or thinly villous. Herbs delicate, 3–6(–9) dm, glabrate or puberulent.
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, clustered, several-branched, from thick woody rootstock or rhizomes;

branches ascending at 20–35º, weakly to moderately or 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, ovate to narrowly elliptic, 2–3.5(–4) × 0.7–3 cm, base cuneate to cordate, apex acute;

petiole 1–2.5 cm;

leaflet blades elliptic to narrowly elliptic or rhombic, 3–7 × 0.5–2.5 cm, lateral veins 7–10 pairs, conspicuously net-veined abaxially, apex acute to obtuse, surfaces glabrate to puberulent.

Racemes

6–25-flowered, 4–25 cm;

flowers in whorls of 2 or 3 or scattered.

5–15-flowered, 7–15 cm;

flowers usually in whorls of 2–4.

Peduncles

2–8 cm;

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

3–5 cm;

bracts deciduous, ovate to lanceolate, 7–14 × 3–5 mm.

Pedicels

3.5–5 mm, villosulous.

5–8 mm, glabrate to puberulent.

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.

2.5–2.9 cm;

calyx 8–11 × 6–8 mm at limb, lobes 2–5 mm, equal to or shorter than tube;

wing and keel petals elliptic to asymmetrically oblong-elliptic;

ovary appressed-pubescent;

ovules 10–18.

Legumes

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

divergent, straight to arcuate, to ca. 45º, 6.5–9 × 0.6–0.8 cm, inconspicuously appressed-pubescent.

Seeds

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

(6–)10–14, brown-black, elliptic, 4–5 × 2–2.5 mm, beaked.

2n

= 36.

Thermopsis montana

Thermopsis divaricarpa

Phenology Flowering (Apr–)May–Jun(–Jul).
Habitat Pine or spruce forests, streamsides, moist, open areas.
Elevation 2000–3000 m. (6600–9800 ft.)
Distribution
from USDA
North America
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; NM; WY
[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.)

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. fraxinifolia, T. gracilis, 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. rhombifolia var. divaricarpa
Name authority Nuttall in J. Torrey and A. Gray: Fl. N. Amer. 1: 388. (1840) A. Nelson: Bot. Gaz. 25: 275, plate 18, fig. 3. (1898)
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