Peniocereus greggii

(Engelmann) Britton & Rose

Contr. U.S. Natl. Herb. 12: 428. 1909.

Common names: Desert night-blooming cereus Arizona queen-of-the-night
Illustrated
Basionym: Cereus greggii Engelmann in F. A. Wislizenus, Mem. Tour N. Mexico, 102. 1848
Treatment appears in FNA Volume 4. Treatment on page 156. Mentioned on page 157.
Revision as of 23:14, 27 May 2020 by imported>Volume Importer

Shrubs, erect to sprawling, usually inconspicuous. Roots turnip-shaped, usually 15–30 × 5–12 cm (much larger ones known). Stems gray-green to gray, simple or with 2–5 branches, 40–120(–300) cm, distally 8–20 mm diam., at midlength ca. 10 mm diam., often narrowed toward base; wood hollow, solid-surfaced cylinders, 4–7 mm diam.; ribs 4–6, prominent; areoles (3.5–)12(–15) mm apart along ribs, circular to elliptic, 2–5 × 2 mm. Spines (9–)11–15(–17) per areole, usually in 3 vertical rows; abaxial 3–5 spines appressed, yellowish white throughout or only at tips, to 3 mm, puberulent when young; adaxial spines black, subulate, to 1 mm. Flowers: nocturnal (remaining open next day), 15–25 cm; scales of flower tubes green, tipped red or brown; outer tepals greenish white with brown to reddish midstripes; inner tepals white or lightly tinged cream or pink (or rarely all rose-pink), lanceolate-attenuate, apiculate, 4–7 cm, attenuate to mucronate; stamens 2.5 cm; anthers cream-yellow, 2 mm; style white, 10–14 cm; stigma lobes 9–11, white. Fruits bright red, darkening in age, ellipsoid, 60–90 × 40–50 mm. Seeds 3–4 × 2–2.5 mm. 2n = 22.

Distribution

V4 301-distribution-map.gif

Ariz., N.Mex., Tex., w Mexico.

Discussion

Varieties 2 (2 in the flora).

Selected References

None.

Key

1 Areoles elliptic, 4-5 × 2 mm; adaxial spines tending to be directed toward tip of plant; abaxial spines directed toward base of plant; flowers 15-17 × 5-6 cm Peniocereus greggii var. greggii
1 Areoles nearly circular, 2 × 2 mm; spines radially spreading; flowers 22-25 × 7-8 cm Peniocereus greggii var. transmontanus