Echinocereus engelmannii
Echinocereus arizonicus
calico cactus, Engelmann's hedgehog cactus, strawberry hedgehog cactus
Arizona claret-cup cactus, Arizona hedgehog cactus
mostly erect, cylindric or somewhat tapering distally, (5–)14–45(–70) × 3–9 cm;
ribs 10–13, crests slightly undulate;
areoles 6–10(–15) mm apart.
usually erect, cylindric, 10–40 × 5–10 cm;
ribs 8–13, slightly undulate;
areoles 10–15 mm apart.
(8–)15–20 per areole, usually straight (curved and twisted in desert mountains and peninsular ranges of California), individual spines with broad zones of different colors: whitish or grayish, dull golden-yellow, or reddish brown to nearly black;
radial spines 6–14 per areole, 8–20(–50) mm;
central spines (2–)4–6(–9) per areole, divergent-porrect, 12–70 mm, abaxial central spine often fading whitish, flat to sharply angled (terete or nearly so in north-central Arizona).
[8–]9–18 per areole, straight or contorted;
radial spines 7–14 per areole, appressed, yellowish to brownish, becoming gray, 5–25 mm;
central spines 1–4 (c Arizona and Mexico) or 3–8 (elsewhere) per areole, spreading to projecting outward, brownish yellow to reddish black, becoming gray, terete (c Arizona) or angled to terete (elsewhere), 15–50 mm.
6–9 × 5–9 cm;
flower tube 13–30 × 10–30 mm;
flower tube hairs 1 mm;
inner tepals bright rose-pink to magenta, often varying from paler to darker in same population, proximally darker, 37–75 × (8–)14–25 mm, tips relatively thin, delicate;
anthers yellow;
nectar chamber 4–6 mm.
5.5–7 × 3.5–5 cm;
flower tube 25–35 mm;
flower tube spines 5–15 mm, hairs to 2 mm;
inner tepals bright orange-red to dark red distally, proximally paler (bases sometimes yellow or whitish), 25–40 × (5–)10–15 mm, tips thick and rigid;
anthers pink to brick red or purple;
nectar chamber 6–10 mm.
red or orangish, 25–45 mm, pulp whitish becoming infused with pink or red from the skin.
green, brownish tinged, 20–30 mm, pulp white.
= 44.
= 22.
Echinocereus engelmannii
Echinocereus arizonicus
The characteristics distinguishing Echinocereus engelmannii from E. fasciculatus to the east are poorly documented, and W. Blum et al. (1998) combined the two as separate subspecies of E. engelmannii. Historically, E. engelmannii has been characterized as having the abaxial central spine in each areole particularly long, pale, and strongly compressed dorsiventrally (sharply angled, hence daggerlike), contrasting with the other spines. In practice that trait is not always diagnostic. Plants called Echinocereus engelmannii var. acicularis L. D. Benson are essentially morphologically and geographically intermediate between those referred to E. fasciculatus and E. engelmannii var. chrysocentrus.
The history of confusion with Echinocereus nicholii has resulted in misidentification of yellow-spined individuals of E. engelmannii.
Spine color polymorphism, common within Echinocereus engelmannii, provided the original basis for varieties chrysocentrus and purpureus. The well-marked, identifiable extremes often occur in populations that include individuals easily assigned to other named varieties, or not assignable to any. L. D. Benson (1969, 1982) and subsequent authors (e.g., N. P. Taylor 1985; W. Blum et al. 1998) have attempted to recognize infraspecific taxa within E. engelmannii. However, one of those is clearly a distinct species (E. nicholii), while the remainder are either too poorly defined or too poorly known to treat fully here. At higher elevations beyond the western edge of the desert, E. engelmannii var. munzii (Parish) P. Pierce & Fosberg has been distinguished by its curving, twisting, gray spines, somewhat resembling spines of westernmost plants of E. triglochidiatus var. mojavensis. Plants of the western Sonoran Desert margin in the Mexican boundary region in California are the typical E. engelmannii var. engelmannii. Similar plants from the opposite, eastern, side of the Sonoran Desert, in Arizona, have been called E. engelmannii var. acicularis L. D. Benson. In the intervening Colorado River Valley is spinier E. engelmannii var. chrysocentrus (Engelmann & J. M. Bigelow) Rümpler. In E. engelmannii var. acicularis at the lowest altitudes, central spines are usually four, in which cases taxonomic segregation from E. engelmannii var. chrysocentrus seems arbitrary. At higher altitudes, plants of E. engelmannii var. acicularis with only one or two central spines per areole are frequent, and the abaxial central spine may be terete instead of angular and daggerlike as in E. engelmannii var. chrysocentrus. The most formidably spiny extremes of the species were segregated as E. engelmannii vars. howei and armatus; however, other individuals in the original populations (type localities) are readily assigned to E. engelmannii var. chrysocentrus. W. Blum et al. (1998) placed all of the above varieties under E. engelmannii subsp. engelmannii.
Plants smaller in all parts and with fewer central spines from north-central Arizona are Echinocereus engelmannii subsp. decumbens (Clover & Jotter) W. Blum & Mich. Lange. L. D. Benson (1969) referred those to var. variegatus (Engelmann & J. M. Bigelow) Rümpler, but the type locality of var. variegatus is in a different region. The status of E. engelmannii var. purpureus L. D. Benson remains uncertain; its similarity to unidentified diploid material found in northern Arizona suggests that it could be a separate species, but more variable than its original diagnosis allowed.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Some populations of diploid claret-cup cacti in southeastern Arizona and southwestern New Mexico have recently been named Echinocereus arizonicus subsp. nigrihorridispinus W. Blum & Rutow, including numerous eastern populations previously misidentified as other taxa. Subspecies arizonicus, of conservation concern, remains known only from central Arizona. Infraspecific taxa within E. arizonicus are not treated formally here because their taxonomic boundaries remain controversial.
Echinocereus arizonicus superficially resembles the dioecious tetraploid E. coccineus var. rosei of the Chihuahuan Desert, and several of its populations were mapped by L. D. Benson (1969, 1982) as part of E. triglochidatus var. neomexicanus (Standley) Standley ex W. T. Marshall. Echinocereus arizonicus subsp. nigrihorridispinus superficially resembles the partially sympatric, synoecious tetraploid recently named E. santaritensis W. Blum & Rutow (a hermaphroditic geographic race of E. coccineus), which has much longer hairs on the flowers, a narrower flower tube, and relatively slender spines. Irrespective of the misleading vegetative similarities between diploid E. arizonicus and its polyploid relatives, E. arizonicus differs strongly from both varieties of the diploid E. triglochidiatus.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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