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.

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.

FNA 2004, Kearney and Peebles 1969

Duration: Perennial Nativity: Native Lifeform: Forb/Herb General: Herbaceous, stout perennials, to 1.5 m tall, stems erect to ascending, mostly branching above, unarmed, with glutinous bands on the internodes, stems usually sparsely leafy, with most leaves occurring near the base of the plant, the upper stems nearly naked. Leaves: Opposite, in roughly equal pairs, thick and fleshy, usually with 1-3 pairs near the plant base, blades broadly ovate to almost round, 5-15 cm long and 4-19 cm wide, bases cordate or rarely rounded, apices rounded or broadly obtuse, adaxial (upper) surfaces dull green to pale green, abaxial(lower) surfaces grayish green and often very pale, both surfaces glabrous or sparsely villous with fine hairs with pale brown or blackish pustulate bases, petioles 3-7 cm. Flowers: White, light purple or rose pink, perianth flower-like, 25-35 mm long, with a long, greenish-bronze tube and petal-like limbs, these abruptly flaring from the tube and glabrous or minutely pubescent externally at the edges (the pubescence most easily seen at the tip of the mature bud), stamens 3, pink to purple, well exserted and 25-40 mm long, flowers borne singly or in ill-defined clusters of 2-5 on branches and stem tips. Fruits: Biturbinate (wedge-shaped and widened in the middle) anthocarp with 10 ribs, 4-8 mm long and 2-4.5 mm wide,the ribs narrow and undulate, with a well-developed, sinuate raised rim, fruits secreting mucilage when wetted. Seeds solitary. Ecology: Found in calcareous soils at about 3,500 ft (1067 m). Distribution: Arizona, Nevada, New Mexico, Texas. Notes: An anthocarp is a fruit with the achene or utricle enclosed in the persistent, fleshy, leathery, or woody base of the calyx. This species has white or bright pinkish-purple flowers with lightly coiling, well-exserted, pink stamens with round, lobed, pinkish anthers. The flower for this species is actually a long perianth tube with petal-like lobes. Look for this species in Arizona in Mohave, Coconino, and Yavapai counties. Ethnobotany: Unknown Synonyms: Boerhavia leiosolena Editor: LCrumbacher2012 Etymology: Anulocaulis comes from the Latin for "ring-stem," from the sticky internodal rings; the meaning of leiosolenus is unknown.