The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

calico cactus, Engelmann's hedgehog cactus, strawberry hedgehog cactus

bonker hedgehog, pinkflower hedgehog cactus

Habit Plants 3–60-branched, ultimately forming somewhat open clumps. Plants 5–35-branched, ultimately forming clumps, branching at or before sexual maturation.
Stems

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.

mostly erect, ovoid to cylindric, 15–30(–50) × 3.5–7 cm;

ribs (11–)12–18(–20), crests slightly undulate;

areoles 8–20 mm apart.

Spines

(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).

(9–)12–17 per areole, straight in short-spined forms, sometimes curved or twisted in long-spined forms, appressed (radial spines) or porrect to spreading or descending (central spines when present), dull yellowish to brown or white to gray, often brown to black especially at bases or tips;

radial spines (9–)11–16 per areole, 5–18 mm;

central spines (0–)1(–3) per areole, 2–100 mm, white to yellow or brown, often becoming gray, all terete.

Flowers

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.

5–7 × 4–9 cm;

flower tube 12–20 × 10–30 mm;

flower tube hairs 1 mm;

inner tepals deep magenta (to dark purple) with darker midstripes, proximally green (to very dark purple), 20–60 × 8.5–20 mm, tips relatively thin and delicate;

anthers yellow;

nectar chamber 2–4 mm.

Fruits

red or orangish, 25–45 mm, pulp whitish becoming infused with pink or red from the skin.

bright red or orange red, 15–25 mm, pulp white (or pale pink).

2n

= 44.

= 22.

Echinocereus engelmannii

Echinocereus bonkerae

Phenology Flowering Mar–Apr; fruiting May–Jul. Flowering Mar–May; fruiting 2 months after flowering.
Habitat Sonoran and Mojave deserts, chaparral, pinyon-juniper woodlands Sonoran Desert upland, interior chaparral, desert grasslands, pinyon-juniper woodlands
Elevation 200-2400 m (700-7900 ft) 700-2000 m (2300-6600 ft)
Distribution
from FNA
AZ; CA; NV; UT; Mexico (Baja California, Sonora)
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ
[WildflowerSearch map]
[BONAP county map]
Discussion

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.)

Plants in most populations of Echinocereus bonkerae have radial spines almost pectinately arranged and central spines very short or absent, creating the superficial appearance of E. dasyacanthus, E. pectinatus, or similar species. Formerly, all short-spined plants in central and southern Arizona were treated as E. bonkerae, including unusually short-spined individuals of E. fendleri and E. fasciculatus. Today we recognize that E. bonkerae, E. fendleri, and E. fasciculatus all vary from short-spined to long-spined.

Populations at the lowest altitude for the species have taller stems and unusually long, slender central spines (to 10 cm); they have recently been named Echinocereus apachensis. Such plants were part of the basis for L. D. Benson’s polyphyletic concept (1969, 1982) of E. fasciculatus var. boyce-thompsonii (see 8. E. fasciculatus).

Echinocereus bonkerae is a poorly defined species, frequently lumped with E. fendleri or E. fasciculatus, and it is not always identifiable in the field. Although rib number, blooming season, habitat preference, and, in particular regions, spine length or central spine presence are helpful characteristics, ploidy level is the most objective criterion for distinguishing E. bonkerae from E. fasciculatus. Immature plants of E. bonkerae are like E. fasciculatus and unlike the immature plants of E. fendleri, which are tuberculate with their spines long, few, soft, and often curved or twisted.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 4. FNA vol. 4.
Parent taxa Cactaceae > subfam. Cactoideae > Echinocereus Cactaceae > subfam. Cactoideae > Echinocereus
Sibling taxa
E. arizonicus, E. berlandieri, E. bonkerae, E. chisosensis, E. coccineus, E. dasyacanthus, E. davisii, E. enneacanthus, E. fasciculatus, E. fendleri, E. ledingii, E. nicholii, E. papillosus, E. pectinatus, E. pentalophus, E. poselgeri, E. pseudopectinatus, E. reichenbachii, E. rigidissimus, E. stramineus, E. triglochidiatus, E. viridiflorus
E. arizonicus, E. berlandieri, E. chisosensis, E. coccineus, E. dasyacanthus, E. davisii, E. engelmannii, E. enneacanthus, E. fasciculatus, E. fendleri, E. ledingii, E. nicholii, E. papillosus, E. pectinatus, E. pentalophus, E. poselgeri, E. pseudopectinatus, E. reichenbachii, E. rigidissimus, E. stramineus, E. triglochidiatus, E. viridiflorus
Synonyms Cereus engelmannii, E. engelmannii var. armatus, E. engelmannii var. chrysocentrus, E. engelmannii var. howei E. apachensis, E. fasciculatus var. bonkerae, E. fendleri var. bonkerae
Name authority (Parry ex Engelmann) Lemaire: Cactées, 56. (1868) Thornber & Bonker: Fantast. Clan, 71, 85, plates opposite 23, 72. (1932)
Web links