Pediocactus knowltonii

L. D. Benson

Cact. Succ. J. (Los Angeles) 32: 193. 1960.

Common names: Knowlton’s minute cactus
EndemicConservation concern
Synonyms: Pediocactus bradyi var. knowltonii (L. D. Benson) Backeberg Pediocactus simpsonii var. knowltonii (L. D. Benson) Halda
Treatment appears in FNA Volume 4. Mentioned on page 215.

Plants branched or unbranched. Stems globular to short cylindric, 0.7–5.5 × 1–3 cm; areoles circular, villous. Spines smooth, relatively hard, all radial, mostly 18–26 per areole, spreading, recurved, or somewhat pectinate, reddish tan, pink, or white, 1–1.5 mm, canescent. Flowers 1–3.5 × 1–2.5 cm; scales and outer tepals essentially entire, often undulate; outer tepals with brownish midstripes to 1.5 mm wide, 4–17 × 4–6 mm; inner tepals pink, oblanceolate, 8–25 × 3–8 mm. Fruits green, drying reddish tan, turbinate,4 × 3 mm. Seeds black, 1.5 × 1–1.2 mm, papillate but not rugose.


Phenology: Flowering spring.
Habitat: Gravel pavements in pinyon-juniper woodlands with mixed sagebrush
Elevation: 2000 m

Discussion

Of conservation concern.

Pediocactus knowltonii is the smallest and rarest member of the genus. The species is very closely related to P. simpsonii; chloroplast DNA sequence analysis provides support that it represents a recent developmental mutation within P. simpsonii (J. M. Porter et al. unpubl.).

Selected References

None.

Lower Taxa

None.
... more about "Pediocactus knowltonii"
Kenneth D. Heil +  and J. Mark Porter +
L. D. Benson +
Knowlton’s minute cactus +
2000 m +
Gravel pavements in pinyon-juniper woodlands with mixed sagebrush +
Flowering spring. +
Cact. Succ. J. (Los Angeles) +
Endemic +  and Conservation concern +
Pediocactus bradyi var. knowltonii +  and Pediocactus simpsonii var. knowltonii +
Pediocactus knowltonii +
Pediocactus +
species +