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chaparral bird's-foot trefoil, large leaf lotus, large-flower lotus

American bird's-foot trefoil, American deervetch, deer-vetch, prairie trefoil, Spanish clover, Spanish lotus

Habit Herbs, perennial, cespitose, sometimes robust, grayish or green, 1–4(–15) dm, not fleshy, ± densely puberulent or strigillose; rhizomatous, woody based. Herbs, annual, solitary or cespitose, green, 0.5–6(–12) dm, not fleshy, glabrate to ± pilose; taprooted.
Stems

1–5+, decumbent to erect, branched, herbaceous, often striate, leafy.

1–10+, erect to procumbent, branched proximally, herbaceous, leafy.

Leaves

irregularly pinnate;

stipules glandlike, conic; petiolate or sessile;

rachis 2–3.5(–5.5) mm, not flattened;

leaflets 7–9(–12), blades usually elliptic to obovate, sometimes ovate, apex acute to obtuse, surfaces sparsely to densely puberulent or villosulous to strigillose.

pinnate;

stipules glandlike;

subsessile to short-petiolate;

rachis 0.5–3(–4) mm, not flattened;

leaflets (1–)3(–5), blades obovate, ovate, or elliptic to lanceolate, margins denticulate or entire, apex acute, surfaces sparsely appressed-hairy.

Inflorescences

3–9(–11)-flowered.

1(or 2)-flowered.

Peduncles

ascending or spreading, 10–80 mm, longer than leaves;

bract 1(–3)-foliolate, distal.

in distal axils, ascending, 3–25 mm, longer than leaves;

bract unifoliolate, distal.

Flowers

12–25 mm;

calyx (4.5–)5.5–10 mm, tube villosulous, lobes subulate;

corolla greenish white, white or yellow, fading to rose or reddish, claws shorter than calyx tube, banner ascending 45–90°, wings longer than banner and keel;

style nearly straight or basally curved, glabrous.

(4–)5–9 mm;

calyx (2.5–)3–6.5 mm, tube pilose, lobes linear-lanceolate, accrescent;

corolla whitish or cream, turning pink or salmon, banner rose-striate, keel tip yellow, claws shorter than calyx tube, banner implicate-ascending to erect, wings ± equaling keel;

style abruptly angled upward 45°, glabrous.

Legumes

persistent, exserted, brown, linear-oblong, straight, turgid, sometimes slightly constricted, incompletely septate, 25–42(–70) × 2–3 mm, leathery, apex short hook-beaked, dehiscent, smooth, margins smooth, thickened, glabrate.

persistent, exserted, spreading or pendent, brown, straight or ± curved, compressed, slightly constricted, not septate, linear-oblong to narrowly oblong, (15–)20–30(–40) × (1.5–)2–2.5 mm, thinly leathery, apex abruptly downward angled and curved, dehiscent, smooth, margins smooth, thickened, glabrous.

Seeds

5–9, olive to reddish brown, mottled, broadly ovoid, smooth.

(3–)5–8, olive to light brown, often black-mottled, oblong, smooth.

Acmispon grandiflorus

Acmispon americanus

Distribution
nw Mexico; California
[WildflowerSearch map]
[BONAP county map]
North America; nw Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

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

Varieties 2 (2 in the flora).

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

Key
1. Herbs densely puberulent or villosulous, usually grayish; ovules 22–30.
var. grandiflorus
1. Herbs strigillose or puberulent, green; ovules ca. 45.
var. macranthus
1. Herbs usually conspicuously pilose, sometimes glabrate; leaflet blades: length 3–3.5 times width.
var. americanus
1. Herbs glabrate; leaflet blades: length 4–5 times width.
var. helleri
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Acmispon Fabaceae > subfam. Faboideae > Acmispon
Sibling taxa
A. americanus, A. argophyllus, A. argyraeus, A. brachycarpus, A. cytisoides, A. decumbens, A. dendroideus, A. denticulatus, A. glaber, A. haydonii, A. intricatus, A. junceus, A. maritimus, A. mearnsii, A. micranthus, A. neomexicanus, A. parviflorus, A. plebeius, A. procumbens, A. prostratus, A. rigidus, A. rubriflorus, A. strigosus, A. tomentosus, A. utahensis, A. wrangelianus, A. wrightii
A. argophyllus, A. argyraeus, A. brachycarpus, A. cytisoides, A. decumbens, A. dendroideus, A. denticulatus, A. glaber, A. grandiflorus, A. haydonii, A. intricatus, A. junceus, A. maritimus, A. mearnsii, A. micranthus, A. neomexicanus, A. parviflorus, A. plebeius, A. procumbens, A. prostratus, A. rigidus, A. rubriflorus, A. strigosus, A. tomentosus, A. utahensis, A. wrangelianus, A. wrightii
Subordinate taxa
A. grandiflorus var. grandiflorus, A. grandiflorus var. macranthus
A. americanus var. americanus, A. americanus var. helleri
Synonyms Hosackia grandiflora, Anisolotus grandiflorus, Lotus grandiflorus, Ottleya grandiflora Trigonella americana, Hosackia americana
Name authority (Bentham) Brouillet: J. Bot. Res. Inst. Texas 2: 390. (2008) (Nuttall) Rydberg: Bull. Torrey Bot. Club 40: 45. (1913)
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