Flora of North America species comparison

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

Echinocereus rigidissimus

Echinocereus arizonicus

Arizona rainbow cactus, rainbow hedgehog cactus

Arizona claret-cup cactus, Arizona hedgehog cactus
Habit Plants few to many branched.
Stems

usually erect, cylindric, 10–40 × 5–10 cm;

ribs 8–13, slightly undulate;

areoles 10–15 mm apart.
Spines

[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.
Flowers

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.
Fruits

green, brownish tinged, 20–30 mm, pulp white.
2n

= 22.

Echinocereus rigidissimus

Echinocereus arizonicus
Phenology Flowering Apr–May; fruiting May–Jul.
Habitat Chihuahuan Desert, desert scrub, interior chaparral, desert grasslands, steep walls of canyons, limestone hills, among granite boulders
Elevation 1400-1900 m (4600-6200 ft)
Distribution
from FNA
AZ; NM; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; NM; Mexico (Chihuahua)
[BONAP county map]
Discussion

Varieties 2 (1 in the flora).

(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.)
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. engelmannii, E. enneacanthus, E. fasciculatus, E. fendleri, E. ledingii, E. nicholii, E. papillosus, E. pectinatus, E. pentalophus, E. poselgeri, E. pseudopectinatus, E. reichenbachii, E. stramineus, E. triglochidiatus, E. viridiflorus
E. berlandieri, E. bonkerae, 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
Subordinate taxa
E. rigidissimus var. rigidissimus
Synonyms Cereus pectinatus var. rigidissimus, E. pectinatus var. rigidissimus E. coccineus var. arizonicus, E. triglochidiatus var. arizon
Name authority (Engelmann) F. Haage: Special Preisverz., 13. (1897) Rose ex Orcutt: Cactography 1926(1): 3. (1926)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Fabaceae, Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America

The species comparison tool is brought to you by:
Northwest Wildflowers