Herbs acaulescent or sub­acau­lescent, to 20 cm, eglan­dular except leaves or rarely stipules and bracts, pubescent. Stems absent, leaves clustered; pseudo­scapes erect, 3–10 cm, usually 1, sometimes to 6, rarely branched proximally; cataphylls 10–20 mm (when present). Leaves palmately 5–7-foliolate; stipules often fragmented on plant, partly connate, ovate, 11–24 × 11–16 mm, scarious, usually eglandular, sparsely pubes­cent; petiole jointed basally, 40–150(–190) mm, shorter than peduncle, hirsute-villous; petiolules 1–2.5 mm; leaflet blades oblanceolate to elliptic, 1.5–4.5(–6) × 0.5–1.3(–1.8) cm, base cuneate, apex acuminate to obtuse, surfaces glandular, abaxially pubescent, adax­ially sparsely so, usually along margins. Peduncles 4–14 cm (8–19 cm in fruit), longer than subtending petiole, setose. Inflorescences disjointing in age at peduncle base, long-ovoid; rachis 2.5–9.5 cm, elon­gating through fruiting, nodes 4–11(–15), 3 flowers per node, internodes 1–5 mm, elongating to 25 mm in fruit; bracts persistent, orbiculate to lanceolate, 7–14 × 2–7 mm, margins pubescent, apex sometimes caudate or emarginate, becoming papery and veined in age. Pedicels 1–2 mm. Flowers 10–15(–22) mm; calyx weakly gibbous-campanulate in fruit, 6–10 mm abaxially, 5–8 mm adaxially, glabrate and eglandular on gibbous portion, sparsely setose and glandular distally; tube stramineous, 4.5–6 mm; lobes triangular, abaxial 2–4 × 2 mm, adaxial 1–2 × 1 mm; corolla dark blue to purple, banner oblanceolate to oval, 13–23 × 4–5 mm with claw 5–6 mm, wings 12–18 × 2–3 mm with claw 5–7 mm, keel 10–15 × 2–3 mm with claw 2–3 mm; filaments 10–12 mm; anthers obovate, 0.3 mm; ovary pubescent apically, style pubescent basally. Legumes globose to ovoid, 6–7 × 4–5 mm, eglandular, sparsely pubescent apically, beak triangular, 4–6 mm, exserted beyond calyx. Seed gray-brown to red-brown, obovoid-reniform, 5–6 × 3–4 mm. 2n = 22.

Phenology: Flowering spring.
Habitat: Calcareous soils, cedar glades.
Elevation: 200–1500 m.

Distribution

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Ala., Ga., Tenn.

Discussion

Pediomelum subacaule is known from Colbert and Franklin counties in Alabama, Catoosa County in Georgia, and Davidson, Maury, Rutherford, and Wilson counties in Tennessee.

Pediomelum subacaule is quite distinct and disjunct from its fellow members of subg. Disarticulatum, this evidenced by its large, partly connate stipules and short, broad calyx lobes, and by being the only species in the subgenus east of the Mississippi River. Pediomelum subacaule is restricted to limestone soil in open cedar glades. Although P. subacaule is well established in the protected cedar glades of Tennessee, its historical range is shrinking due to habitat loss. Several historical sites that were, or still are, active limestone quarries have no remaining evidence of P. subacaule, particularly in Alabama and Georgia.

Selected References

None.

Lower Taxa

None.