Sclerocactus sileri

(L. D. Benson) K. D. Heil & J. M. Porter

Haseltonia 2: 39. 1994.

Common names: Siler fishhook cactus
EndemicConservation concern
Basionyms: Sclerocactus pubispinus var. sileri L. D. Benson Cacti Arizona ed. 3, 23. 179. 1969
Synonyms: Pediocactus pubispinus subsp. sileri (L. D. Benson) Halda Pediocactus whipplei subsp. busekii (Hochstätter) Halda Sclerocactus whipplei subsp. busekii Hochstätter
Treatment appears in FNA Volume 4. Treatment on page 205. Mentioned on page 198, 199.

Stems unbranched (2-branched), green, depressed-spheric to short cylindric, 4–8.5 × 3–5.5 cm; ribs usually (12–) 13 (–14), not well developed, tubercles prominent on low ribs. Spines obscuring stems or nearly so; radial spines 6–8 (–12) per areole, acicular, elliptic in cross-section, 5–15 × 0.5–0.8 mm; central spines 4–5 per areole; abaxial central spines 1–2 per areole, white, gray, or purplish tinged, turned or curving somewhat downward, angled, strongly hooked, slightly contorted, terete to angled, 12–35 × 0.5–1 mm; lateral central spines 2 per areole, similar to abaxial but slightly shorter, usually not hooked; adaxial central spines 1–2 per areole, erect, recurved, white to tan, strongly flattened, conspicuous, 13–40 × 0.8–2 mm. Flowers funnelform to campanulate, 2.5–3 × 2–3 cm; outer tepals with brownish and yellowish margins, larger oblanceolate, 10–17 × 5–8 mm, apex mucronate, margins membranous, crisped or minutely toothed; inner tepals yellow, sometimes suffused with brown, largest tepals oblanceolate, 15–25 × 5–7 mm, apex mucronate; filaments white to greenish white; anthers yellow; styles minutely but densely papillate Fruits dehiscent along 2–4 vertical slits, green, turning red to tan, ovoid, 8–25 × 8–14 (–22) mm, dry; scales few, membranous, scarious-margined, minutely toothed or fringed. Seeds black to light-brown, 2.7–3 × 2.2–2.5 mm; testa with rounded papillae.


Phenology: Flowering late Apr–May.
Habitat: Silty sand or clay soils, often with gravel, grama grasslands with dropseed, yucca, hedgehog cactus, sagebrush, and snakeweed, pinyon-juniper woodlands
Elevation: 1600-1700 m

Discussion

Of conservation concern.

As far as is known, based on field investigations and herbarium collections, Sclerocactus sileri is restricted to northeast Coconino County, Arizona. This enigmatic cactus shares morphologic characteristics with both Sclerocactus whipplei (F. Hochstätter 1996) and S. pubispinus. The floral morphology and color is reminiscent of S. whipplei; however, the adaxial central spine morphology and fruit dehiscence is much like that found in S. pubispinus and S. spinosior. Phylogenetic analyses of chloroplast DNA sequences (J. M. Porter et al. 2000) provided evidence that S. sileri is the sister taxon to a clade including S. brevispinus, S. whipplei, S. cloverae, S. glaucus, S. parviflorus, S. wetlandicus, and S. wrightiae. Therefore, there is no support for immediate links between S. sileri and either S. whipplei or S. pubispinus.

Selected References

None.

Lower Taxa

None.

... more about "Sclerocactus sileri"
purplish tinged +, gray +  and white +
1.2 cm12 mm <br />0.012 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
downward +  and turned +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.1 cm1 mm <br />0.001 m <br />) +
1.3 cm13 mm <br />0.013 m <br /> (4 cm40 mm <br />0.04 m <br />) +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.2 cm2 mm <br />0.002 m <br />) +
cushionlike +
spine-bearing +
circular to linear +
deciduous +  and persistent +
connected +
elliptic +  and pyriform +
0.8 cm8 mm <br />0.008 m <br /> (2 cm20 mm <br />0.02 m <br />) +
Kenneth D. Heil +  and J. Mark Porter +
(L. D. Benson) K. D. Heil & J. M. Porter +
hardened +
Sclerocactus pubispinus var. sileri +
triangular +
pink +  and purplish-pink or black +
subulate +  and acicular +
proliferating +
flattened +  and cylindric +
Siler fishhook cactus +
mucilaginous +
notched +
1600-1700 m +
not separating +
white +  and greenish white +
6 cm60 mm <br />0.06 m <br /> (7 cm70 mm <br />0.07 m <br />) +
2.5 cm25 mm <br />0.025 m <br /> (3 cm30 mm <br />0.03 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 />) +
1.4 cm14 mm <br />0.014 m <br /> (2.2 cm22 mm <br />0.022 m <br />) +
persistent +, long +  and deciduous +
8mm;25mm +
papillate +
0.8 cm8 mm <br />0.008 m <br /> (1.4 cm14 mm <br />0.014 m <br />) +
Silty sand or clay soils, often with gravel, grama grasslands with dropseed, yucca, hedgehog cactus, sagebrush, and snakeweed, pinyon-juniper woodlands +
1.5 cm15 mm <br />0.015 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
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 +
0.7 cm7 mm <br />0.007 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
yellowish +  and brownish +
toothed +  and crisped +
purple +, yellowish-brown +, reddish-brown +  and greenish lavender +
Purple (?) +, Pink (?) +, Rose (?) +, Gold (?) +, Cream (?) +  and White (?) +
1 cm10 mm <br />0.01 m <br /> (1.7 cm17 mm <br />0.017 m <br />) +
deciduous +  and persistent +
Flowering late Apr–May. +
mucilaginous +
abscission +
ridgelike +  and nipple--shaped +
greenish +  and white +
tuberculate +
scarious-margined +
fringed +  and toothed +
membranous +
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 />) +
0.27 cm2.7 mm <br />0.0027 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
shiny +  and glossy +
obovoid;pyriform;obovoid;pyriform;lenticular-reniform;comma--shaped;spheric +
0.22 cm2.2 mm <br />0.0022 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
Endemic +  and Conservation concern +
black +, purplish-pink +, pink +, brown +, straw colored +, gray +  and white +
curved +  and straight +
deciduous +  and persistent +
5mm +  and 15mm +
6 (?) +  and 8 (?) +
acicular +
hard +  and rigid +
0.05 cm0.5 mm <br />5.0e-4 m <br /> (0.08 cm0.8 mm <br />8.0e-4 m <br />) +
decurrent +
15 cm150 mm <br />0.15 m <br /> (20 cm200 mm <br />0.2 m <br />) +
4cm;8.5cm +
depressed-spheric +  and short cylindric +
succulent +
3cm;5.5cm +
creamy white +, yellow +, green +  and pink +
flat-topped +
tuberculate +
Pediocactus pubispinus subsp. sileri +, Pediocactus whipplei subsp. busekii +  and Sclerocactus whipplei subsp. busekii +
adventitious +
tuberlike +
epipetric +  and epiphytic +
Sclerocactus sileri +
Sclerocactus +
species +
1.5 cm15 mm <br />0.015 m <br /> (5 cm50 mm <br />0.05 m <br />) +
lanceolate to oblanceolate +
0.4 cm4 mm <br />0.004 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
dull +  and glossy +
papillate +
coalescent +
distinct +
epiphytic;epiphytic;epiphytic +
barrel-shaped +  and spheric +