Contr. U.S. Natl. Herb. 12: 374. 1909.

Common names: Ringstem
Etymology: Latin anulus, ring, and caule, stem, in reference to the sticky internodal rings
Treatment appears in FNA Volume 4. Treatment on page 28. Mentioned on page 14, 17, 2.
FNA4 P4 Boerhavia torreyana.jpegBoerhavia torreyana
Boerhavia coulteri var. coulteri
Anulocaulis annulatus
Anulocaulis leiosolenus var. leiosolenus
Bee F. Gunn
Bee F. Gunn
Bee F. Gunn
Bee F. Gunn

Herbs, usually short to long-lived perennial, occasionally annual, stout, pubescent to glabrate, from slender and spongy or massive and woody taproots. Stems erect to ascending, unarmed, with glutinous bands on internodes. Leaves in pairs, ± equal in size in each pair, long petiolate, thick and fleshy, base ± symmetric. Inflorescences terminal, pedunculate, widely paniculate, flowers ultimately borne singly, in subumbellate clusters, or in glomerules; bracts persistent, not accrescent, 1–2 at base of pedicel, distinct, minute, lanceolate, dark, opaque. Flowers bisexual, chasmogamous; perianth radially symmetric or slightly bilaterally symmetric, tubular-funnelform, constricted beyond ovary, tube abruptly flared to 5-lobed limb; stamens 3 or 5, exserted; styles exserted beyond stamens; stigmas peltate. Fruits biturbinate or fusiform, constricted beyond base, apex umbonate, stiffly coriaceous, smooth or irregularly wrinkled, glabrous, with 10 narrow ribs and an equatorial flange or wing, or 5-angulate with a low rib between angles and no equatorial flange, or fusiform and smooth or with 10 low, linear ribs and sometimes with incomplete equatorial low, linear ridge, eglandular or glandular-puberulent.


sw United States, n Mexico


Species 5 (4 in the flora).

Species of Anulocaulis have been considered to belong in a broadly circumscribed Boerhavia, the western A. annulatus most recently so in regional treatments. F. R. Fosberg (1978) argued for an inclusive Boerhavia, and suggested that workers emphasizing differences might wish to recognize segregate genera, as is done in this work.

Flowers of Anulocaulis, particularly in those species with large ones, are slightly bilaterally symmetric because of curvature of the tube, variation in the amount of curvature of the limb, and the downward sweep of the stamens and the style.


1 Perianth 8-10 mm, tube externally villous; fruits without prominent equatorial ridges (sometimes faint in Anulocaulis annulatus) > 2
1 Perianth 9-35 mm, tube glabrous or minutely pubescent at edge; fruits with prominent equatorial flange > 3
2 Flowers 5-15 in umbel-like clusters; fruits broadly fusiform, with 10 narrow, well- defined linear ribs Anulocaulis annulatus
2 Flowers usually borne singly; fruits turbinate, bluntly 5-angled, ribs indefinite Anulocaulis eriosolenus
3 Perianth lobes flared but not reflexed; perianth 25-35 mm Anulocaulis leiosolenus
3 Perianth lobes sharply reflexed; perianth 9-10 mm Anulocaulis reflexus

"thin" is not a number."thick" is not a number.

... more about "Anulocaulis"
wrinkled +  and smooth +
fusiform;5-angulate;umbonate +
coriaceous +
Richard W. Spellenberg +
Standley +
glutinous +
unequal +
woody +, leathery +  and fleshy +
undulate;plane;linear;ovate or more or less round +
succulent +  and fleshy +
opaque +  and dark +
persistent +
distinct +
lanceolate +
minute +  and not accrescent +
corollalike +  and petaloid +
Ringstem +
sw United States +  and n Mexico +
curved +  and straight +
Latin anulus, ring, and caule, stem, in reference to the sticky internodal rings +
inconspicuous +  and showy +
1 +  and 80 +
chasmogamous +  and bisexual +
fusiform +  and biturbinate +
constricted +
lateral +  and terminal +
pubescent +  and glabrous +
sinuate +  and entire +
tubular-funnelform +
constricted +
Contr. U.S. Natl. Herb. +
spellenberg1993a +
glandular-puberulent +
thick +  and thin +
fibrous;fleshy +
membranaceous +
ribbed +, 10-ribbed +  and 5-ribbed +
pubescent +, glabrous +  and warty +
wrinkled +
erect +  and ascending +
fusiform +  and linear +
filiform +
Anulocaulis +
Nyctaginaceae +
gland-tipped +
abruptly flared;5-lobed +
annual +, perennial +  and long-lived +
pubescent +  and glabrate +