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silverleaf Indian breadroot, silverleaf scurfpea

Rydberg's Indian breadroot, Rydberg's scurfpea

Habit Herbs caulescent, to 100 cm, mostly glandular throughout, silvery-sericeous. Herbs acaulescent, to 20 cm, mostly glandular and pubescent throughout.
Stems

± erect, branched distally, branches subtended by leaves, leaves dispersed along stems, more so distally;

pseudoscapes to 10 cm (when present);

cataphylls 9–20 mm, glabrous or pubescent apically.

absent, leaves clustered;

pseudoscapes 5–7 cm (when present);

cataphylls 7–9 mm, striate, clustered apically.

Leaves

palmately 3–6-foliolate;

stipules tardily deciduous proximally, persistent distally, linear, 8–18 × 2–4 mm, rarely glandular, glabrous;

petiole not swollen or jointed basally, slightly canaliculate, 2–55 mm, strigose;

petiolules 1–4 mm;

leaflet blades oblanceolate to narrowly elliptic or orbiculate, 1.1–4.5 × 0.6–2.2 cm, base attenuate, apex acute, acuminate to apiculate, surfaces abaxially sparsely to densely sericeous, rarely eglandular, adaxially glabrous or less sericeous.

pinnately 3-foliolate;

stipules persistent, lanceolate to oblanceolate-oblong, 5–7(–12) × 2.5–3 mm, stramineous, eglandular, glabrous;

petiole swollen proximally or not, not jointed, (30–)50–120 mm;

petiolules 2 mm;

leaflet blades orbiculate to obovate-trullate, lateral 2 usually asymmetrical, 1.5–2.5(–3.2) × 1–2.4 cm, base broadly cuneate or truncate, apex broadly acute, surfaces abaxially white-pubescent, adaxially white-hirsute along veins and margins.

Inflorescences

persistent, oblong, elongate;

rachis 0–6 cm, exposed, nodes (1 or)2–4(–8), (1–)3 flowers per node, internodes 3–7(–17) mm;

bracts persistent, linear to lanceolate or elliptic, 3–9 × 1.5–4 mm, sericeous.

disjointing in age at peduncle base, ovate to elliptic;

rachis 1.4–1.6 cm, crowded, nodes 4–7, 3 flowers per node;

bracts persistent, caudate-lanceolate, 5–8 × 2–3.5 mm, pubescent throughout or only at apex.

Peduncles

3–9 cm, longer than subtending petiole, densely white-strigose.

2–10 cm, shorter than subtending petiole, glabrous proximally, pubescent distally.

Pedicels

0.5–1 mm.

1–3 mm.

Flowers

7–11 mm;

calyx elongating and becoming broadly and shallowly campanulate in fruit but not gibbous, 6–8 mm abaxially, 4–6 mm adaxially, glandular (glands often hidden by hairs), sericeous (sometimes sparsely so);

tube 2–3 mm;

lobes linear-lanceolate to lanceolate, abaxial 4.5–5 × 2–2.5 mm, adaxial 1.5 × 1 mm;

corolla deep blue, banner oblanceolate to obovate or orbiculate, 6–7.5 × 3.5–5 mm with claw 1.5–2 mm, wings 6–7 × 1.5–2.5 mm with claw 2–2.5 mm, keel 5–6 × 1.5–2 mm with claw 2–3 mm;

filaments 4.5–5 mm;

anthers elliptic, 0.4 mm;

ovary glabrous proximally, canescent on distal 2/3, style canescent basally.

12–20 mm;

calyx gibbous-campanulate in fruit, 10–15(–17) mm, pubescent throughout or teeth only;

tube 5–7 mm;

lobes linear or linear-lanceolate, abaxial 8–8.5 × 1–1.5 mm, adaxial 6–7.5 × 0.5–1 mm;

corolla white and blue-purple, banner white to pale purple, oblanceolate, 15–17 × 6–7 mm with claw 4.5–5.5 mm, wings blue-purple, 12–14 × 2.5–3 mm with claw 5.5–6.5 mm, keel dark purple, 14–16 × 2.5–3 mm with claw 8.5 mm;

filaments 16 mm;

anthers elliptic, 0.7 mm;

ovary glabrous, style glabrous.

Legumes

narrowly oblong, 5–6 × 3–4.5 mm, obscurely glandular, tomentose, beak 3–5 mm, equal to or slightly longer than calyx.

oblong-ellipsoid, 5–7 × 3.5–4 mm, eglandular, pubescent apically, beak 4–5 mm, about as long as calyx.

Seed

red-brown, round-reniform, 4–5 × 3–4 mm, dull.

black, ellipsoid-reniform, 3.5–6 × 2.5–4 mm.

2n

= 22.

Pediomelum argophyllum

Pediomelum humile

Phenology Flowering summer. Flowering spring.
Habitat Grasslands. Shallow, rocky clay or limestone soils, shortgrass prairies, shrublands.
Elevation 200–1500 m. (700–4900 ft.) 700–2000 m. (2300–6600 ft.)
Distribution
from FNA
CO; IA; IL; KS; MN; MO; MT; ND; NE; NY; OK; SD; TX; WI; WY; AB; MB; SK
[WildflowerSearch map]
[BONAP county map]
from FNA
TX; Mexico (Coahuila)
[BONAP county map]
Discussion

Pediomelum argophyllum is unique in the genus in its gray, silvery pubescence, earning it the common name silverleaf Indian breadroot. It has one of the widest distributions of its congeners, ranging from Canada to Texas, but seems more prevalent in the northern states. It has been used by native cultures for food or medicine for at least 2500 years (D. F. Dexter et al. 2014).

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

Pediomelum humile, historically known from along the Rio Grande in Texas (Val Verde County) and Mexico, is very rare and on the verge of extinction. Several known populations have been destroyed by urban development in the recent past. The few populations in existence today are located near Del Rio and are all in danger of extirpation due to human influences. Pediomelum humile is in the Center for Plant Conservation’s National Collection of Endangered Plants.

Psoralea humilis (Rydberg) J. F. Macbride 1922, an illegitimate name (not Miller 1768), pertains here.

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

Source FNA vol. 11. FNA vol. 11.
Parent taxa Fabaceae > subfam. Faboideae > Pediomelum Fabaceae > subfam. Faboideae > Pediomelum
Sibling taxa
P. aromaticum, P. californicum, P. canescens, P. castoreum, 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
P. argophyllum, P. aromaticum, P. californicum, P. canescens, P. castoreum, P. cuspidatum, P. cyphocalyx, P. digitatum, P. epipsilum, P. esculentum, 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
Synonyms Psoralea argophylla Psoralea rydbergii
Name authority (Pursh) J. W. Grimes: Mem. New York Bot. Gard. 61: 69. (1990) Rydberg in N. L. Britton et al.: N. Amer. Fl. 24: 24. (1919)
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