Southwestern Ringstem

Anulocaulis leiosolenus occurs as isolated, islandlike populations that are homogeneous within but differ slightly between populations. The turbinate fruits with prominent ribs and equatorial flange ridge, and the long-tubular perianths, are unifying features. Pubescence, when present, is inconspicuous on the perianth, and is best seen on tips of mature buds.

Herbs, stout perennial. Stems 0.5-1.5 m. Leaves: 1-3 pairs near base; petiole 3-7 cm; blade broadly ovate to almost round, 5-15 × 4-19 cm, base cordate, rarely rounded, apex rounded or broadly obtuse, adaxial surface dull green to pale green, abaxial surface grayish green, often very pale, both surfaces glabrous or sparsely villous with fine hairs with pale brown or blackish pustulate bases. Flowers borne singly or in ill-defined clusters of 2-5 on branches of inflorescence; perianth 25-35 mm, tube greenish bronze, limbs white, pink, or rose-pink, abruptly flared from tube, glabrous or minutely pubescent externally at edge (pubescence most easily seen at tip of mature bud); stamens 3, exserted 25-40 mm. Fruits biturbinate, 4.2-8 × 2.6-4.6 mm, secreting mucilage when wetted; ribs 10, narrow, undulate; equatorial flange well developed, sinuate.

Boerhavia leiosolena Torrey in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 172. 1859 (as Boerhaavia)

Anulocaulis leiosolenus (Torr.) Standley, Contr. U. S. Nat. Herb
12: 375. 1909.
Boerhaavia leiosolena Torr. Bot. Mex. Bound. Surv. 172. 1859. Acleisanthes nummularia M. E. Jones, Contr. West. Bot. 10: 43. 1902. Boerhaavia nummularia M. K. Jones; Prain, Ind. Kew. Suppl. 4: 27. 1913.
Plants erect, 6-10 dm. high, sparsely branched below, the branches stout, glaucous, glabrous; leaves 1 or 2 pairs at the base of the stem, the petioles stout, 2-11 cm. long, the blades reniform to broadly oval, rhombic-orbicular, or ovate-oval, 3.5-15 cm. long, 3.5-12.5 cm, wide, deeply cordate to truncate at the base, broadly rounded at the apex, rather coarsely sinuate, thick-coriaceous, yellowish-green on the upper surface and when young tomentulose, beneath glaucescent and tomentulose or villous when young but early glabrate and gland-dotted; inflorescence much branched, the branches stout, naked, the flowers fasciculate or in dense spikes, short-pedicellate; bracts minute, ovate, coriaceous, glabrous; perianth yellowishgreen, 2.5-3 cm. long, glabrous, gradually dilated above into a narrow limb; stamens 5, short-exserted, fruit biturbinate, 5-6 mm. long, glaucous, in age developing at the middle a rigid horizontal wing 6-7 mm. in diameter; seed biturbinate, 3 mm. long, pale-brown.
Type locality: In gypseous soil, Great Canyon of the Rio Grande, 70 miles below Kl Paso,
Texas.
Distribution: In strongly alkaline soil, western Texas to Arizona and Nevada.

Anulocaulis leiosolenus (Torr.) Standley, Contr. U. S. Nat. Herb
12: 375. 1909.
Boerhaavia leiosolena Torr. Bot. Mex. Bound. Surv. 172. 1859. Acleisanthes nummularia M. EJones, Contr. West. Bot. 10: 43. 1902. Boerhaavia nummularia M, E. Jones; Prain, Ind. Kew. Suppl. 4: 27. 1913.
Plants erect, 6-10 dm. high, sparsely branched below, the branches stout, glaucous, glabrous; leaves 1 or 2 pairs at the base of the stem, the petioles stout, 2-11 cm. long, the blades reniform to broadly oval, rhombic-orbicular, or ovate-oval, 3.5-15 cm. long, 3.5-12.5 cm. wide, deeply cordate to truncate at the base, broadly rounded at the apex, rather coarsely sinuate, thick-coriaceous, yellowish-green on the upper surface and when young tomentulose, beneath glaucescent and tomentulose or villous when young but early glabrate and gland-dotted; inflorescence much branched, the branches stout, naked, the flowers fasciculate or in dense spikes, short-pedicellate; bracts minute, ovate, coriaceous, glabrous; perianth yellowish-green, 2.5-3 cm. long, glabrous, gradually dilated above into a narrow limb; stamens 5, short-exserted . fruit biturbinate, 5-6 mm. long, glaucous, in age developing at the middle a rigid horizontal wing 6-7 mm. in diameter; seed biturbinate, 3 mm. long, pale-brown.
Type Texas.