Apios priceana

Vines twining; tuber 1, oblate-spheroidal, 15–20 cm diam. Stems terete, brownish green, glabrous or reflexed-pubescent. Leaves 18–27 cm; rachis 30–37 mm between lateral and terminal leaflets, 34–52 mm between lateral leaflets, glabrous or slightly hairy; stipules 7–8.6 × 0.5–0.7 mm; petiole 70–7 mm, glabrous or slightly hairy; pulvinus 3–4 mm, glabrous or hairs scattered; stipels narrowly triangular, 0.3–0.4 × 0.1–0.2 mm, sericeous; petiolule 3.5–4 mm, slightly hairy to tomentose; leaflet blades ovate to ovate-lanceolate, 50–100 × 5–60 mm, base obtuse or rounded, apex caudate, apiculate, surfaces glabrous or strigose, mostly along major veins. Inflorescences 55–70-flowered, 12–16 cm; bracts early deciduous, 2.5–3.25 mm; bracteoles 5–6.5 × 1–1.8 mm. Pedicels 4–5 mm, glabrous or sparsely pubescent. Flowers in clusters of 2 or 3 on small tubercles; calyx green, hemispheric, 4.8–5.3 mm, glabrous or sericeous, abaxial lobe lanceolate-acuminate, 3–4 × 1.9–2.1 mm, lateral lobes shallowly triangular, 0.9–1.1 × 2–2.3 mm, adaxial lobe almost obsolete, shallowly triangular, 0.8–1 × 1.9–2.3 mm; corolla pale green and rose-purple; banner broadly elliptic, 23–26 × 15–20 mm, stylobos 5.8–7.8 mm; wings narrowly elliptic, falcate, 19–21 × 2.3–2.8 mm (to 4.5–5 mm wide at apex); keel incurved, 18–19 × 8–9 mm, triangular pouch present at middle; stamens 20–24 mm, filaments connate most of their length; pistil disk 0.8–1 mm; ovary 13–15 × 0.9–1.1 mm, glabrous or slightly hairy, mostly along sutures; style 8–11 mm, bearded with simple hairs; ovules 8–12. Legumes brownish red (with tan lines when dry), 12–15(–18) × 0.6–1 cm, base attenuate, apex acuminate; endocarp silvery white. Seeds 8–12, olive green becoming brown when dry, ellipsoid to oblong, 7.2–11 × 4.5–5.5 mm, glaucous; hilum 3.3–4 × 1.4–1.6 mm. 2n = 22.

Phenology: Flowering summer.
Habitat: Rocky, open woods, forest borders, mixed oak woods, limestone, drainage areas.
Elevation: 60–200 m.

Ala., Ky., Miss., Tenn.

Discussion

Apios priceana is designated as threatened throughout its range. The species is apparently extirpated from Illinois (M. Woods 2005).

Apios priceana is in the Center for Plant Conservation’s National Collection of Endangered Plants.

Selected References

None.

Lower Taxa