Coryphantha duncanii

(Hester) L. D. Benson

Cact. Succ. J. (Los Angeles) 41: 189. 1969.

Common names: Duncan’s pincushion cactus
EndemicConservation concern
Basionym: Escobesseya duncanii Hester Desert Pl. Life 13: 192. 1941
Synonyms: Escobaria dasyacantha var. duncanii (Hester) N. P. Taylor Escobaria duncanii (Hester) Backeberg
Treatment appears in FNA Volume 4. Treatment on page 231. Mentioned on page 222, 223, 230.

Plants unbranched (rarely to 8 mature branches), white bristly spines obscuring stem. Roots dominated by a short or narrowly conic, carrotlike, succulent taproot, 1/3–1/2 of stem diam. Stems deep-seated, inconspicuous, obovoid, ovoid, or spheric to ± conic, 2.5–6 × 1–3.4 cm; tubercles 3–6 × 2.6–4 mm, moderately soft; areolar glands absent; parenchyma not mucilaginous; druses in pith and cortex abundant but nearly microscopic; pith 1/2 of lesser stem diam.; medullary vascular system absent. Spines (21–) 31–44 (–55) per areole, all snowy white, dark tips (tan to reddish-brown) on medium and large spines; radial spines (18–) 20–41 per areole, (4–) 6–9 (–10) × 0.03–0.2 mm; subcentral spines 0–12 per areole; outer central spines (1–) 3–9 (–17) per areole, appressed or (usually) slightly projecting; inner central spines (spines most likely to interpreted as central) 0 (–1) per areole, ascending, descending, or porrect, straight, longest spines (6–) 7–14 (–19) × 0.17–0.27 mm. Flowers nearly apical, 15–30 × 13–19 mm; outer tepals conspicuously fringed; inner tepals 14 per flower, margins white or cream (to light pink), midstripes pinkish to brown or brownish green, proximally white, 8–12 × 1.5–3 mm; outer filaments white or pinkish; anthers bright-yellow; stigma lobes usually 4, dark green to bright-yellow. Fruits bright red throughout, ellipsoid, cylindric, or clavate, 11–20 × 3–5 mm, not very succulent; floral remnant deciduous. Seeds black, ± spheric, ± 1.2 mm, pitted. 2n = 22.


Phenology: Flowering Feb–Mar(-May); fruiting mostly May.
Habitat: Limestone slopes, mostly in crevices of massive limestone outcrops
Elevation: 700-1700 m

Discussion

Of conservation concern.

Coryphantha duncanii is inconspicuous, difficult to identify, and usually rare. Other coryphanthas in its range have thicker spines, except for C. chaffeyi and C. dasyacantha. Coryphantha duncanii resembles a stunted, crevice-limited growth form of C. dasyacantha but has caducous floral remnant. It is closely related to C. zilziana Boedeker of Mexico.

Selected References

None.

Lower Taxa

None.
... more about "Coryphantha duncanii"
bright-yellow +
cushionlike +
circular to linear +
0.9 cm9 mm <br />0.009 m <br /> (1 cm10 mm <br />0.01 m <br />) +
deciduous +  and persistent +
connected +
0.6 cm6 mm <br />0.006 m <br /> (0.9 cm9 mm <br />0.009 m <br />) +
hourglass--shaped +
0.003 cm0.03 mm <br />3.0e-5 m <br /> (0.02 cm0.2 mm <br />2.0e-4 m <br />) +
Allan D. Zimmerman +  and Bruce D. Parfitt +
(Hester) L. D. Benson +
spineless +  and naked +
hardened +
Escobesseya duncanii +
triangular +
curved +  and straight +
0.4 cm4 mm <br />0.004 m <br /> (5.5 cm55 mm <br />0.055 m <br />) +
proliferating +
flattened +  and cylindric +
Duncan’s pincushion cactus +
with mucilage +  and mucilaginous +
N.Mex. +  and Tex. +
microscopic +
700-1700 m +
not separating +
1.5 cm15 mm <br />0.015 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 />) +
13mm;19mm +
indehiscent +
persistent +, long +  and deciduous +
11mm;20mm +
clavate +, cylindric +  and ellipsoid +
succulent +
0.3 cm3 mm <br />0.003 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
Limestone slopes, mostly in crevices of massive limestone outcrops +
porrect +, descending +  and ascending +
0.45 cm4.5 mm <br />0.0045 m <br /> (4 cm40 mm <br />0.04 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 +
1.4 cm14 mm <br />0.014 m <br /> (1.9 cm19 mm <br />0.019 m <br />) +
7mm +  and 14mm +
0.017 cm0.17 mm <br />1.7e-4 m <br /> (0.027 cm0.27 mm <br />2.7e-4 m <br />) +
cream +  and white +
fringed +  and toothed +
small +
white +, pinkish +  and brown or brownish green +
0.8 cm8 mm <br />0.008 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
1.5mm +  and 3mm +
projecting +  and appressed +
pinkish +  and white +
not mucilaginous +
deciduous +  and persistent +
Flowering Feb–Mar(-May) +  and fruiting mostly May. +
mucilaginous +
ridgelike +  and nipple--shaped +
Cact. Succ. J. (Los Angeles) +
colorless +  and white greenish or pinkish +
3;2;2;30 +
erose +  and entire +
rudimentary +
triangular +
arillate +  and strophiolate +
0.08 cm0.8 mm <br />8.0e-4 m <br /> (0.35 cm3.5 mm <br />0.0035 m <br />) +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
glossy +  and shiny +
spheric +
Endemic +  and Conservation concern +
adventitious +
snowy white +  and white +
curved +  and straight +
deciduous +  and persistent +
20 (?) +  and 41 (?) +
annulate-ridged +, hairlike +, daggerlike +, subulate +  and acicular +
hard +  and rigid +
differentiated +
decurrent +
unsegmented +
2.5cm;6cm +
deep-seated +
inconspicuous +
tuberculate +
spheric +  and more or less conic +
succulent +
1cm;3.4cm +
dark green +  and bright-yellow +
protruding +  and flat +
large +  and small +
tuberculate +
Escobaria dasyacantha var. duncanii +  and Escobaria duncanii +
adventitious +
1/3 +  and 1/2 +
carrotlike +  and conic +
epipetric +  and epiphytic +
Coryphantha duncanii +
Coryphantha +
species +
dull +  and glossy +
pitted +  and raised-reticulate +
3mm +  and 6mm +
conic +  and hemispheric or cylindric +
2.6mm +  and 4mm +
epiphytic;epiphytic;epiphytic +