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scurfpea, subterranean Indian breadroot

beaver dam breadroot, beaver Indian breadroot, Indian breadroot

Habit Herbs usually acaulescent, rarely subacaulescent, to 25 cm, pubescent throughout and eglandular or sparsely glandular with pale, sunken obscure glands on leaflets and/or calyx tubes only. Herbs acaulescent or subacaulescent, to 16 cm, glandular (with obvious blond to dark brown glands) on leaflets, less so on bracts and stipules, mostly silver-strigose throughout.
Stems

short-erect, with decumbent laterals, decumbent stems 0–6 cm, overtopped by leaves, leaves clustered;

pseudoscapes usually 1, unbranched, rarely 2, 0.5–9.5 cm;

cataphylls 5–20 mm.

short-erect, sometimes with proximal, decumbent lateral stems to 25 cm, unbranched or sparsely branched, leaves appearing clustered at base or alternate along short stem, with clusters of leaves or inflorescences distally;

pseudoscapes to 10(–14) cm;

cataphylls 5–20 mm, glabrous or strigose.

Leaves

palmately (3–)5-foliolate;

stipules persistent, linear-lanceolate to elliptic, 4–19 × 2–6 mm, appressed-pubescent;

petiole not obviously jointed basally, (20–)30–210 mm;

petiolules 1–3 mm;

leaflet blades elliptic to lanceolate, oblanceolate, or rhombic, 1–7.5 × 0.3–4 cm, base cuneate, apex acuminate, surfaces glabrate to sparsely pubescent.

usually palmately, rarely pseudopalmately, (3–)5 or 6-foliolate;

stipules persistent, triangular or lanceolate to narrowly oblong, 5–13.5 × 2–5 mm, pubescent;

petiole slightly enlarged and jointed basally, slightly canaliculate, (30–)65–150 mm;

petiolules 1.5–2.5 mm;

leaflet blades oblanceolate or orbiculate to elliptic, (1.5–)2–4.5 × (1.5–)2.3–4 cm, base attenuate, apex broadly acute to rounded or retuse, surfaces abaxially gray-green and pubescent, adaxially yellow-green and sparsely pubescent along veins to pubescent, not white-veined.

Inflorescences

disjointing in age at peduncle base, ovate to oblong;

rachis 0.5–6 cm, elongating slightly in fruit, nodes 3–15, 3 flowers per node, internodes crowded in flower, elongating to 25 mm in fruit;

bracts mostly persistent or very tardily deciduous, linear to oblanceolate or rhombic, 3–11 × 1.5–4.5 mm, appressed-pubescent.

disjointing in age at peduncle base, ellipsoid to ovoid;

rachis 1.5–1.6 cm, elongating to 2–5.5 cm in fruit, nodes 3–11, 2 or 3 flowers per node;

bracts tardily deciduous or persistent, narrowly elliptic or spatulate to oval, 3.5–8 × 3–7 mm, pubescent.

Peduncles

1–14 cm, shorter than subtending petiole, subappressed-pubescent.

(1.5–)2.4–7 cm, shorter than subtending petiole, appressed-spreading pubescent.

Pedicels

1–5 mm.

0–2 mm.

Flowers

11–18 mm;

calyx weakly gibbous-campanulate in fruit, 9–15 mm abaxially, 6–14 mm adaxially, usually eglandular, very rarely glandular on tube, pubescent;

tube 2.5–6 mm;

lobes subulate or linear-lanceolate to lanceolate, abaxial 6–10 × 1.5–3(–4) mm, adaxial 4.5–9 × 1–1.5 mm;

corolla lavender to purple, banner paler, sometimes also marginally white, elliptic to obovate, 11–18 × 4–7 mm with claw 2–5 mm, wings 11–16 × 2–3 mm with claw 3.5–6 mm, keel 6–12 × 2–3 mm with claw 2.5–7 mm;

filaments 6–11 mm;

anthers round to elliptic, 0.3–0.5 mm;

ovary glabrous or pubescent apically, style pubescent basally.

9–13 mm;

calyx gibbous-campanulate in fruit, 10–12 mm abaxially (elongating to 20 mm in fruit), 9–10.5 mm to adaxial lobe (elongating to 14 mm in fruit), usually eglandular, strigose to setose;

tube 3–4 mm;

abaxial lobe broadly oblanceolate, 4–5 × 4–4.5 mm, often with 3 prominent veins, adaxial lobes linear, 4–5 × 1–1.5 mm;

corolla ochroleucous with purple tinge to purple, banner usually elliptic, 9–13 × 3.5–5 mm with claw 2–4 mm, wings 10–13 × 2 mm with claw 4–4.5 mm, keel 6.5–8 × 2 mm with claw 3–4 mm;

filaments 6–7.5 mm;

anthers elliptic, 0.4 mm;

ovary pubescent apically, style glabrous, sometimes pubescent basally.

Legumes

ellipsoid-lanceoloid to oblong, 5–6.5 × 3–5 mm, eglandular, glabrous or slightly pubescent, beak 7–19 mm, exserted beyond calyx.

ellipsoid to ovoid, 6–8 × 5–6 mm, eglandular, strigose, beak 8–11(–15) mm, equal to or longer than calyx.

Seed

red-brown or gray, globose-reniform, 4–5 × 2.5–3.5 mm, smooth to somewhat rugose.

gray-green to dark brown, narrowly reniform, 5.5–6 × 3.5–4 mm, rugose, dull.

2n

= 22.

Pediomelum hypogaeum

Pediomelum castoreum

Phenology Flowering spring.
Habitat Sand or sandy soils, open desert scrub communities.
Elevation 400–1000 m. (1300–3300 ft.)
Distribution
from USDA
w United States; c United States
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NV
[BONAP county map]
Discussion

Varieties 3 (3 in the flora).

J. W. Grimes (1990) recognized three varieties under Pediomelum hypogaeum. Many specimens exist with intermediate traits that obscure strong delineations between taxa.

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

Pediomelum castoreum is known from Mohave County in Arizona, San Bernardino County in California, and Clark and Lincoln counties in Nevada.

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

Key
1. Peduncles 1–3.5 cm, less than 1/2 as long as sub­tending petiole.
var. hypogaeum
1. Peduncles (1.7–)4–14 cm, more than 1/2 as long as subtending petiole.
→ 2
2. Peduncles appressed-pubescent; leaflet blades lanceolate to elliptic.
var. scaposum
2. Peduncles hirsute-villous; leaflet blades oblan­ceolate to rhombic.
var. subulatum
Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Pediomelum Fabaceae > subfam. Faboideae > Pediomelum
Sibling taxa
P. argophyllum, P. aromaticum, P. californicum, P. canescens, P. castoreum, P. cuspidatum, P. cyphocalyx, P. digitatum, P. epipsilum, P. esculentum, P. humile, P. latestipulatum, P. linearifolium, P. megalanthum, P. mephiticum, P. palmeri, P. pariense, P. pentaphyllum, P. piedmontanum, P. reverchonii, P. rhombifolium, P. subacaule, P. tenuiflorum, P. verdiense
P. argophyllum, P. aromaticum, P. californicum, P. canescens, P. cuspidatum, P. cyphocalyx, P. digitatum, P. epipsilum, P. esculentum, P. humile, P. hypogaeum, P. latestipulatum, P. linearifolium, P. megalanthum, P. mephiticum, P. palmeri, P. pariense, P. pentaphyllum, P. piedmontanum, P. reverchonii, P. rhombifolium, P. subacaule, P. tenuiflorum, P. verdiense
Subordinate taxa
P. hypogaeum var. hypogaeum, P. hypogaeum var. scaposum, P. hypogaeum var. subulatum
Synonyms Psoralea hypogaea Psoralea castorea
Name authority (Nuttall) Rydberg in N. L. Britton et al.: N. Amer. Fl. 24: 21. (1919) (S. Watson) Rydberg in N. L. Britton et al.: N. Amer. Fl. 24: 22. (1919)
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