Echinomastus johnsonii (Parry ex Engelm.) E.M. Baxter
Family: Cactaceae
Johnson's little barrel cactus
[Sclerocactus johnsonii (Parry ex Engelm.) N.P. Taylor]
Echinomastus johnsonii image
Tony Frates  
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. Flowering (Feb-)Mar-May; fruiting Apr-Jun. Mojave desert scrub and upper edge of Sonoran desert scrub, rocky slopes, gravelly hills; 500-1400 m; 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.

Plant: Stems generally 1, 10-25 cm, 5-10 cm diam, ovoid to cylindric; ribs 17-21, prominent; tubercles distinct Leaves: spines yellow or pink to reddish, central 4-8, radial 9-10 Flowers: solitary, bisexual, sessile, ± radial, 5-8 cm diam, greenish yellow, pink, or magenta; ovary scaly; scaly Fruit: 7-15 mm, 3-5 mm diam, becoming dry, scaly; scales widely cordate, ciliate; Seed reniform, tubercled, black Misc: Granitic areas, creosote-bush scrub; 500-1200 m.; Apr-May
Echinomastus johnsonii image
Tony Frates  
Echinomastus johnsonii image
Bethany Lund  
Echinomastus johnsonii image
Bethany Lund  
Echinomastus johnsonii image
Bethany Lund  
Echinomastus johnsonii image
Liz Makings  
Echinomastus johnsonii image
Liz Makings  
Echinomastus johnsonii image
Liz Makings  
Echinomastus johnsonii image
Liz Makings  
The National Science Foundation
This project made possible by National Science Foundation Award 1410069