Boerhavia coulteri var. coulteri

Illustrated
Synonyms: Boerhavia rosei Standley
Treatment appears in FNA Volume 4. Treatment on page 27.

Stems 2–8 dm. Leaf blades 10–50 × 6–32 mm. Flowers: pedicel 0.2–1.6 mm; bracts at base of perianth usually 2; perianth 1–2 mm distal to constriction; stamens 2–3(–4), slightly exserted. Inflorescences terminal clusters, axis 15–60 mm. Fruits (4–)7–20(–22) per cluster, usually overlapping by 50–100% of their length, or 2–4 in group, separated by small gap from next group and with distal fruits overlapping, pale tan, narrowly obpyramidal, 2.5–3.2(–3.6) × (0.9–)1.1(–1.4) mm (l/w: [2.2–]2.5–3.1[–3.3]), apex bluntly conic-truncate, round-truncate, or truncate; ribs obtuse, each often with sharp ridge, slightly rugose near sulci; sulci 0.1–0.2 times as wide as base of ribs, slightly rugose.


Phenology: Flowering late spring–early fall.
Habitat: Sandy or loamy soils in arid grasslands, among brush, roadsides in deserts and cultivated areas
Elevation: [100-]500-1400 m

Distribution

V4 42-distribution-map.gif

Ariz., N.Mex., Utah, Mexico (Sinaloa, Sonora).

Discussion

Most plants of Boerhavia coulteri var. coulteri have fruit apices that are bluntly conic- or round-truncate. Along the Santa Cruz River particularly, some plants have abruptly truncate fruits; those plants represent the phase known as B. rosei. Early in the twentieth century, J. J. Thornber proposed the name “B. standleyi” for such plants but never published it. P. C. Standley (1911) described the ribs of B. rosei as narrow, adding in 1918 that the sulci were broad and open. As the type demonstrates, the relative breadth of the ribs and sulci is exactly the reverse, confusing regional botanists for several generations.

Selected References

None.

Lower Taxa

None.

Richard W. Spellenberg +
(Hooker f.) S. Watson +
Senkenbergia coulteri +
Ariz. +, N.Mex. +, Utah +, Mexico (Sinaloa +  and Sonora). +
[100-]500-1400 m +
Sandy or loamy soils in arid grasslands, among brush, roadsides in deserts and cultivated areas +
Flowering late spring–early fall. +
Proc. Amer. Acad. Arts +
Illustrated +
Boerhavia rosei +
Boerhavia coulteri var. coulteri +
Boerhavia coulteri +
variety +