Pediomelum esculentum |
Pediomelum |
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Indian breadroot, large Indian breadroot, prairie turnip |
breadroot, Indian breadroot |
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Habit | Herbs usually caulescent, rarely subacaulescent to acaulescent, to 50 cm, eglandular and pubescent throughout. | Herbs, perennial, unarmed; roots deep, apically swollen, woody, rarely fibrous with scattered tubers. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | erect, usually unbranched, sometimes branched basally, leaves dispersed along stem and arising nearly perpendicular to it; pseudoscapes 0.5–2 cm; cataphylls 0.5–15 mm, striate. |
erect to ascending, decumbent, prostrate, or absent, glabrous or pubescent. |
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Leaves | palmately (3–)5-foliolate; stipules persistent, broadly lanceolate proximally to linear-lanceolate distally, 10–20 × 2–8 mm, stramineous basally, eglandular, glabrate to sparsely pubescent, hairs semi-erect; petiole not jointed basally, (2–)30–100(–150) mm; petiolules 1.5–4 mm; leaflet blades elliptic to oblanceolate, 2–4(–6) × 0.7–2.3 cm, base attenuate to cuneate, apex broadly acute to rounded or retuse, surfaces abaxially pubescent, adaxially glabrate except on midvein. |
clustered or alternate, usually palmate, pseudopalmate, or pinnately 3-foliolate (rarely phylloidal in P. rhombifolium), glandular or eglandular; stipules present; petiolate or sessile; stipels absent; leaflets (1–)3–7(or 8), blade margins entire, surfaces glabrous or pubescent. |
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Inflorescences | persistent (not disjointing at base of peduncle in fruit), elliptic to oblong; rachis 1.6–7 cm, elongating slightly in fruit, nodes (6–)8–15, (2 or)3 flowers per node; bracts persistent, oblanceolate to elliptic, 5–15 × (0.5–)4–9 mm, glabrate to sparsely pubescent, hairs semi-erect. |
3–51-flowered, axillary, pseudoracemes; bracts present. |
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Peduncles | (0.5–)5–12(–15) cm, shorter than subtending petiole, pilose. |
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Pedicels | 1–3 mm. |
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Flowers | 12–20 mm; calyx strongly gibbous-campanulate in fruit, 13–16 mm abaxially, 12–14 mm adaxially, eglandular, pubescent; tube 5–6 mm; lobes linear or linear-lanceolate to elliptic, abaxial 7.5–10 × 2–2.5 mm, adaxial 4–7 × 1–1.5 mm; corolla violet to blue-purple, banner sometimes paler, oblanceolate, 17–18 × 6 mm with claw 7–8 mm, wings 15–16.5 × 3–3.5 mm with claw 6–6.5 mm, keel 12–12.5 × 3 mm with claw 6–6.5 mm; filaments 11–14 mm; anthers elliptic, 0.5 mm; ovary pubescent apically, style glabrous apically. |
papilionaceous; calyx campanulate, usually enlarging through fruiting, rarely not enlarging, but flaring backwards and tearing along a lateral sinus (P. tenuiflorum), lobes 5, abaxial often enlarged; corolla usually purple, blue, violet, or lavender, sometimes white, yellow or ochroleucous, rarely brick red or salmon-pink; stamens 10, diadelphous; anthers dorsifixed; style arched to sharply reflexed. |
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Fruits | legumes, persistent on receptacle (except deciduous in P. tenuiflorum), sessile or short-stipitate, compressed, straight or curved, oblong, ellipsoid to lanceoloid, ovoid, obovoid, or globose, beaked, glabrous or pubescent, dehiscence circumscissile. |
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Legumes | oblong, 4–6 × 2.5–3.5 mm, eglandular, pubescent, beak 9–13(–16) mm, exserted beyond calyx. |
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Seed | brown, reniform, 4 × 3 mm, somewhat rugose. |
1, globose to ellipsoid, oblong, or reniform, usually smooth; hilum usually not surrounded by raised, white ridge. |
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x | = 11. |
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2n | = 22. |
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Pediomelum esculentum |
Pediomelum |
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Phenology | Flowering late spring–summer. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Prairies, grasslands, open pine woodlands. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 500–2000 m. (1600–6600 ft.) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
AR; CO; IA; IL; KS; MN; MO; MT; ND; NE; NM; OK; SD; TX; WI; WY; AB; MB; SK
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North America; n Mexico |
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Discussion | Pediomelum esculentum was once one of the main sources of starch for Native American tribes of the Great Plains, eaten fresh, boiled, dried, or ground into flour and used as a thickening agent. Use of the root for food and barter was documented by Lewis and Clark on their historic expedition across the United States (Mer. Lewis and W. Clark 2003). Pediomelum esculentum ranges in morphology from strongly caulescent to acaulescent with no apparent geographical structuring in this most widespread species. J. W. Grimes (1990) placed this species in subg. Pediomelum due to its persistent inflorescences. Molecular phylogenetic and network analyses suggest a split affinity for P. esculentum between both subgenera, suggesting that this may be an intermediate form and bridge between his subgenera or the groupings suggested by D. J. Ockendon (1965) based on habit—groupings somewhat supported by molecular phylogenies (A. N. Egan and K. A. Crandall 2008, 2008b). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species 25 (25 in the flora). Pediomelum has been classically recognized as Psoralea Linnaeus, a genus now circumscribed for psoraleoid species primarily of Africa. P. A. Rydberg (1919–1920) segregated Pediomelum from Psoralea based on the transverse dehiscence of the pod and a gibbous calyx, characters also supported as diagnostic of Pediomelum by J. W. Grimes (1990), along with a persistent fruit base following dehiscence. Molecular phylogenetic studies have also confirmed the natural grouping that is Pediomelum (A. N. Egan and K. A. Crandall 2008). Psoralidium was dissolved, with remaining species placed in Ladeania. J. W. Grimes (1990) divided Pediomelum into three subgenera: subg. Leucocraspedon J. W. Grimes to accommodate two prostrate species with salmon, brick red, or yellowish flowers and a white ridge surrounding the hilum of the seed; subg. Pediomelum to accommodate those species that are usually caulescent and have a persistent inflorescence; and subg. Disarticulatum J. W. Grimes whose members are largely acaulescent and whose inflorescence becomes disjointed with age at the base of the peduncle. Molecular phylogenetic studies strongly support subg. Leucocraspedon, and somewhat follow membership of the other two subgenera, but not completely. Associations surrounding P. aromaticum and P. esculentum, in particular, are problematic (A. N. Egan and K. A. Crandall 2008, 2008b). Endemism is high in Pediomelum with most species having restricted geographical ranges. This, coupled with habitat degradation from grazing and urbanization, has resulted in a number of Pediomelum species being listed as rare, threatened, or endangered (K. S. Walter and H. J. Gillett 1998). The rapid and recent evolutionary diversification of Pediomelum may have contributed to the level of endemism within the group (A. N. Egan and K. A. Crandall 2008b) and has made species delimitation within the genus difficult. Considerable differences of opinion exist as to what criteria should be used for species delimitation and how many species exist within the genus, particularly for those in the southwestern United States. Several species of Pediomelum are of historical economic importance. Pediomelum esculentum was once an important starch source for Native American tribes of the Great Plains, as recorded on the historic Lewis and Clark Expedition (Mer. Lewis and W. Clark 2003). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 11. | FNA vol. 11. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Fabaceae > subfam. Faboideae > Pediomelum | Fabaceae > subfam. Faboideae | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Subordinate taxa | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Synonyms | Psoralea esculenta | Psoralea subg. pediomelum | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | (Pursh) Rydberg in N. L. Britton et al.: N. Amer. Fl. 24: 20. (1919) | Rydberg in N. L. Britton et al.: N. Amer. Fl. 24: 17. (1919) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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