Echinocereus davisii

Houghton

Cact. Succ. J. (Los Angeles) 2: 466, fig. 1931.

Common names: Davis’s hedgehog cactus
IllustratedEndemic
Synonyms: Echinocereus viridiflorus var. davisii (Houghton) W. T. Marshall ex Backeberg
Treatment appears in FNA Volume 4. Mentioned on page 170.

Plants tiny, usually unbranched in the wild, nearly covered by soil (often having only 2–5 areoles exposed). Stems erect, spheric, (1–) 2–3 × 1–2 (–2.5) cm; ribs 6–9, crests poorly defined, undulate; areoles of largest plants 6–7 (–10) mm apart. Spines 8–14 (–15) per areole, in relatively old plants curving irregularly in random directions, gray or white, some or all tipped black, dark reddish-brown, or dull reddish purple; radial spines 8–14 per areole, ± pectinately arranged, (5–) 10–15 (–19) mm; central spines 0 (–1) per areole, terete, 10–12 mm, closely resembling largest radial spines. Flowers 1.5–2 × 1.5–2 (–2.7) cm; flower tube 5–8 × 5–10 mm; flower tube hairs very short, inconspicuous; inner tepals bright yellow-green, often with maroon midstripes, 9–18 × 2.7–3.8 mm, tips relatively thin and delicate; anthers yellow; nectar chamber 1 mm. Fruits purplish brown or remaining green when ripe, 5.5–9 (–11) mm, pulp white. 2n = 22.


Phenology: Flowering Feb–Mar; fruiting 1 1/2-2 months after flowering.
Habitat: Semidesert grasslands, novaculite outcrops
Elevation: 1200-1300 m

Discussion

The relatively heavy, brown-and-white, often slightly contorted radial spines of Echinocereus davisii help to distinguish these tiny plants from seedlings of their larger congeners; remains of flowers and fruits, such as scattered flower tube spine-clusters, provide proof of sexual maturity. Echinocereus davisii is easily distinguished from E. viridiflorus; it is parapatric with E. viridiflorus without evidence of introgression. Echinocereus davisii is less compatible with E. viridiflorus than any varieties of E. viridiflorus are with one another (E. E. Leuck 1980).

Echinocereus davisii is in the Center for Plant Conservation’s National Collection of Endangered Plants.

Selected References

None.

Lower Taxa

None.

"thin" is not a number.

... more about "Echinocereus davisii"
cushionlike +
confluent +, circular +  and linear +
circular to linear +
deciduous +  and persistent +
hourglass--shaped +
0.1 cm1 mm <br />0.001 m <br /> (5.2 cm52 mm <br />0.052 m <br />) +
Allan D. Zimmerman +  and Bruce D. Parfitt +
Houghton +
hardened +
triangular +
curved +  and straight +
1 cm10 mm <br />0.01 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
proliferating +
flattened +  and cylindric +
Davis’s hedgehog cactus +
mucilaginous +
undulate +
1200-1300 m +
not separating +
2 cm20 mm <br />0.02 m <br /> (2.7 cm27 mm <br />0.027 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (2 cm20 mm <br />0.02 m <br />) +
unisexual +  and bisexual +
2.6 cm26 mm <br />0.026 m <br /> (5 cm50 mm <br />0.05 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (0.8 cm8 mm <br />0.008 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (2.6 cm26 mm <br />0.026 m <br />) +
0.5 cm5 mm <br />0.005 m <br /> (1 cm10 mm <br />0.01 m <br />) +
1.5cm;2cm +
white;remaining green when ripe , 5.5-9(-11) mm , pulp;purplish brown +
dehiscent +  and indehiscent +
persistent +, long +  and deciduous +
spheric +  and narrowly obovoid +
2 cm20 mm <br />0.02 m <br /> (3 cm30 mm <br />0.03 m <br />) +
Semidesert grasslands, novaculite outcrops +
0.9 cm9 mm <br />0.009 m <br /> (1.8 cm18 mm <br />0.018 m <br />) +
2.7mm;3.8mm +
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 cm10 mm <br />0.01 m <br /> (?) +
smooth +  and tuberculate +
deciduous +  and persistent +
Flowering Feb–Mar +  and fruiting 1 1/2-2 months after flowering. +
mucilaginous +
0.7 cm7 mm <br />0.007 m <br /> (1 cm10 mm <br />0.01 m <br />) +
0.6 cm6 mm <br />0.006 m <br /> (0.7 cm7 mm <br />0.007 m <br />) +
ridgelike +  and nipple--shaped +
Cact. Succ. J. (Los Angeles) +
triangular +
arillate +  and strophiolate +
0.04 cm0.4 mm <br />4.0e-4 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
rugose +  and tuberculate +
spheric;obovoid +
tuberculate +
Illustrated +  and Endemic +
arranged +  and radial +
0 cm0 mm <br />0 m <br /> (0.3 cm3 mm <br />0.003 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (1.9 cm19 mm <br />0.019 m <br />) +
reddish purple +, dull +, dark reddish-brown +, tipped black +, white +  and gray +
curved +  and straight +
deciduous +
3mm +  and 150mm +
8 (?) +  and 14 (?) +
roughened +  and smooth +
acicular +  and subulate +
1 cm10 mm <br />0.01 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
0.01 cm0.1 mm <br />1.0e-4 m <br /> (0.25 cm2.5 mm <br />0.0025 m <br />) +
decurrent +
unsegmented +
2 cm20 mm <br />0.02 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
yellow-green +  and dark green +
2cm;3cm +
spheric +
0 cm0 mm <br />0 m <br /> (40 cm400 mm <br />0.4 m <br />) +
succulent +
1cm;2cm +
yellowish green +  and green +
tuberculate +
Echinocereus viridiflorus var. davisii +
adventitious +
tuberlike +
epipetric +  and epiphytic +
Echinocereus davisii +
Echinocereus +
species +
dull +  and glossy +
inconspicuous +
epiphytic;epiphytic;epiphytic +
decumbent +, pendent +, sprawling +, ascending +  and erect +
barrel-shaped +  and spheric +