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"
cushionlike +
deciduous +  and persistent +
elliptic +, pyriform +, oval +  and circular +
Kenneth D. Heil +  and J. Mark Porter +
L. D. Benson +
hardened +
triangular +
curved +  and straight +
terete +  and flat +
proliferating +
flattened +  and cylindric +
Knowlton’s minute cactus +
mucilaginous +
2000 m +
not separating +
1 cm10 mm <br />0.01 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
15 cm150 mm <br />0.15 m <br /> (30 cm300 mm <br />0.3 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (15 cm150 mm <br />0.15 m <br />) +
1cm;2.5cm +
reddish tan;green +
persistent +, long +  and deciduous +
turbinate +
dry +, fleshy +  and juicy +
3 cm30 mm <br />0.03 m <br /> (?) +
Gravel pavements in pinyon-juniper woodlands with mixed sagebrush +
0.8 cm8 mm <br />0.008 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
oblanceolate +
deciduous +  and persistent +
rudimentary +
flat +  and terete +
nearly +  and microscopic +
0 cm0 mm <br />0 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
tuberculate +
fluted;spheric;depressed-spheric or club-shaped +
entire +  and fimbriate +
0mm +  and 1.5mm +
0.4 cm4 mm <br />0.004 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
deciduous +  and persistent +
Flowering spring. +
mucilaginous +
ridgelike +  and nipple--shaped +
Cact. Succ. J. (Los Angeles) +
greenish +  and white +
3;2;2;30 +
undulate +
thin +  and broad +
arillate +  and strophiolate +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (?) +
not rugose +  and papillate +
pyriform;obovoid +
0.1 cm1 mm <br />0.001 m <br /> (0.12 cm1.2 mm <br />0.0012 m <br />) +
Endemic +  and Conservation concern +
white +, pink +  and reddish tan +
curved +  and straight +
deciduous +  and persistent +
6mm +  and 30mm +
recurved +  and spreading +
18 (?) +  and 26 (?) +
pectinate +
0.1 cm1 mm <br />0.001 m <br /> (0.15 cm1.5 mm <br />0.0015 m <br />) +
0.03 cm0.3 mm <br />3.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
decurrent +
unsegmented +
gray-green +  and green +
0.7cm;5.5cm +
globular +  and short cylindric +
succulent +
1cm;3cm +
yellow +  and green +
tuberculate +
Pediocactus bradyi var. knowltonii +  and Pediocactus simpsonii var. knowltonii +
adventitious +
tuberlike +
epipetric +  and epiphytic +
Pediocactus knowltonii +
Pediocactus +
species +
dull +  and glossy +
not confluent +
mammillate +, cylindroid +, truncate-conic +, conic +  and pyramidal +
0.2 cm2 mm <br />0.002 m <br /> (1 cm10 mm <br />0.01 m <br />) +
unbranched +  and branched +
epiphytic;epiphytic;epiphytic +
hanging +  and erect to prostrate +
barrel-shaped +  and spheric +