Echinomastus johnsonii

(Parry ex Engelmann) E. M. Baxter

Calif. Cact., 75. 1935.

Basionym: Echinocactus johnsonii Parry ex Engelmann in S. Watson, Botany (Fortieth Parallel), 117. 1871 (as johnsoni)
Synonyms: Echinomastus johnsonii var. lutescens (Parish) Wiggins Neolloydia johnsonii (Parry ex Engelmann) N. P. Taylor Sclerocactus johnsonii
Treatment appears in FNA Volume 4. Treatment on page 194. Mentioned on page 192, 193.

Stems 10–25 × 7–15 cm; ribs (13–)18–21; areoles (14–)21–26 mm apart along ribs; areolar glands present at least seasonally. Spines 13–24 per areole, pale yellow to grayish lavender to maroon; radial spines 9–16 per areole; abaxial (shortest) radial spine 6–19 × (0.2–)0.4–0.6 mm; adaxial and lateral (longest) radial spines ca. 27–40 mm; central spines 4–9 per areole, present at all ages, 27–41 × (0.7–)1.1–1.4 mm; longest central spine straight to strongly decurved; abaxial central spine porrect, ca. 27–40 mm Flowers 4–6.5 × 4–7.7 cm; inner tepals yellow or pink to magenta, basal portions blotched with maroon, 2.5–3.7 × 1–1.8 cm; stigma lobes yellowish white to green. Fruits dehiscent only along single, longitudinal split, ± spheric, 17–18 mm. 2n = 22.

Phenology: Flowering (Feb-)Mar–May; fruiting Apr–Jun.
Habitat: Mojave desert scrub and upper edge of Sonoran desert scrub, rocky slopes, gravelly hills
Elevation: 500-1400 m


V4 362-distribution-map.gif

Ariz., Calif., Nev., Utah.


Echinomastus johnsonii varies geographically in both flower and spine color. The yellow-flowered plants have been named E. johnsonii var. lutescens. The pink-flowered plants occur in separate populations, as far as is known, to the north of the yellow-flowered plants, but the interface between the two forms is poorly understood.

Selected References


Lower Taxa

... more about "Echinomastus johnsonii"
Allan D. Zimmerman +  and Bruce D. Parfitt +
(Parry ex Engelmann) E. M. Baxter +
Echinocactus johnsonii +
Ariz. +, Calif. +, Nev. +  and Utah. +
500-1400 m +
Mojave desert scrub and upper edge of Sonoran desert scrub, rocky slopes, gravelly hills +
Flowering (Feb-)Mar–May +  and fruiting Apr–Jun. +
Calif. Cact., +
Illustrated +  and Endemic +
Echinomastus johnsonii var. lutescens +, Neolloydia johnsonii +  and Sclerocactus johnsonii +
Echinomastus johnsonii +
Echinomastus +
species +