Echinocereus engelmannii
Echinocereus viridiflorus
calico cactus, Engelmann's hedgehog cactus, strawberry hedgehog cactus
green pitaya, nylon hedgehog cactus, small-flower h edgehog 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.
erect, spheric to short cylindric, (3–)8–30(–35) × 2.8–9 cm;
ribs 10–20, crests prominent, slightly to conspicuously undulate;
areoles 3–12 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).
(13–)18–30(–55) per areole, stiff (flexible) and straight (or slightly curved), sometimes pectinately arranged, red-and-white, red-and-yellow, yellow-and-white, whitish, yellowish, or purplish, tips often darker;
radial spines 12–38(–45) per areole, appressed to spreading, (2–)4–18 mm;
central spines 0–17 per areole, spreading to projecting, terete (subulate), 3–5–40 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.
2–3.5 × (1–)1.5–3 cm;
flower tube (4–)5–12 × 5–15 mm;
flower tube hairs 1–2 mm;
inner tepals shades of yellow or brown, frequently tending towards yellowish green or brick red (rarely carmine in Davis Mountains populations), often with darker purplish maroon midstripes, 10–25 × 2–4 mm, tips relatively thin and delicate;
anthers yellow;
nectar chamber 1–2[–3] mm.
red or orangish, 25–45 mm, pulp whitish becoming infused with pink or red from the skin.
yellowish green to dark green, dark purple, or reddish tinged, 6–17 mm, pulp white.
= 44.
= 22.
Echinocereus engelmannii
Echinocereus viridiflorus
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.)
A large number of infraspecific taxa have been recognized within Echinocereus viridiflorus, differing in various combinations of flower color, spine color, number and thickness of central spines, and other characters, including floral scent. Populations of E. viridiflorus with the most numerous central spines (five or more per areole), giving the plants a bristly appearance, are often considered a separate species, E. chloranthus. Wherever such taxa are sympatric they intergrade; all are freely interfertile in the greenhouse.
The common morphotype at middle altitudes in Texas and southeastern New Mexico has 0–2(–3) central spines and is called either Echinocereus viridiflorus var. cylindricus (Engelmann) Rümpler or E. chloranthus var. cylindricus (Engelmann) N. P. Taylor. Typical E. viridiflorus (var. viridiflorus), with small stems and relatively pure yellow flowers, extends from central New Mexico and the Texas Panhandle to South Dakota. One of the segregate taxa, Echinocereus chloranthus var. neocapillus D. Weniger, is remarkable for its softly hairy, not sharply spiny, seedlings. Populations of E. viridiflorus from Big Bend National Park, usually with reddish or russet flowers, have been named E. russanthus D. Weniger. Yellow-spined plants may occur at high altitudes. A poorly defined, yellow-spined population near Marathon, Texas, has been named E. viridflorus var. correllii L. D. Benson. Bristly red-spined plants from New Mexico have recently been segregated as E. chloranthus subsp. rhyolithensis W. Blum & Mich. Lange.
Echinocereus viridiflorus in the broad sense may prove paraphyletic with respect to E. davisii, but they are phenologically isolated, with E. davisii flowering earlier and thus appearing reproductively isolated in the wild.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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