FNA: Echinocereus pectinatus vs. Echinocereus davisii

	Echinocereus pectinatus	Echinocereus davisii
	Mexican comb hedgehog, rainbow cactus	Davis' hedgehog cactus
Habit		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.

	Echinocereus pectinatus	Echinocereus davisii
Phenology		Flowering Feb–Mar; fruiting 1 1/2-2 months after flowering.
Habitat		Semidesert grasslands, novaculite outcrops
Elevation		1200-1300 m (3900-4300 ft)
Distribution	TX; n Mexico [WildflowerSearch map] [BONAP county map]	TX [BONAP county map]
Discussion	Varieties 2 (1 in the flora). At least in the United States, Echinocereus pectinatus (diploid) has only pink or purple flowers, unlike the polymorphic species E. dasyacanthus (tetraploid). Echinocereus pectinatus differs from the entire E. reichenbachii species group in that the areoles of its relatively thick-walled flower tube have stouter spines and much shorter hairs. Superficially similar species west of the Continental Divide, formerly associated with E. pectinatus (E. pseudopectinatus, E. rigidissimus, and some Sonoran species), are more closely related to the E. reichenbachii species group with densely bristly flower buds and delicate, ephemeral inner tepals. Echinocereus pectinatus var. pectinatus is endemic to Mexico; reports from the United States were misidentifications of var. wenigeri, E. pseudopectinatus (in Arizona), and unusually short-spined plants of E. dasyacanthus. (Discussion copyrighted by Flora of North America; reprinted with permission.)	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. (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. pentalophus, E. poselgeri, E. pseudopectinatus, E. reichenbachii, E. rigidissimus, E. stramineus, E. triglochidiatus, E. viridiflorus	E. arizonicus, E. berlandieri, E. bonkerae, E. chisosensis, E. coccineus, E. dasyacanthus, 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. pectinatus var. wenigeri
Synonyms	Echinocactus pectinatus	E. viridiflorus var. davisii
Name authority	(Scheidweiler) Engelmann: in F. A. Wislizenus, Mem. Tour N. Mexico, 109. (1848)	Houghton: Cact. Succ. J. (Los Angeles) 2: 466, fig. (1931)
Web links	WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Echinocereus davisii

Mexican comb hedgehog, rainbow cactus

Davis' hedgehog cactus

Habit

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.

= 22.

Echinocereus davisii

Phenology

Flowering Feb–Mar; fruiting 1 1/2-2 months after flowering.

Habitat

Semidesert grasslands, novaculite outcrops

Elevation

1200-1300 m (3900-4300 ft)

Distribution

TX; n Mexico

[WildflowerSearch map]

[BONAP county map]

Discussion

Varieties 2 (1 in the flora).

At least in the United States, Echinocereus pectinatus (diploid) has only pink or purple flowers, unlike the polymorphic species E. dasyacanthus (tetraploid). Echinocereus pectinatus differs from the entire E. reichenbachii species group in that the areoles of its relatively thick-walled flower tube have stouter spines and much shorter hairs. Superficially similar species west of the Continental Divide, formerly associated with E. pectinatus (E. pseudopectinatus, E. rigidissimus, and some Sonoran species), are more closely related to the E. reichenbachii species group with densely bristly flower buds and delicate, ephemeral inner tepals. Echinocereus pectinatus var. pectinatus is endemic to Mexico; reports from the United States were misidentifications of var. wenigeri, E. pseudopectinatus (in Arizona), and unusually short-spined plants of E. dasyacanthus.

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

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.

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

Source

FNA vol. 4.

Parent taxa

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. pentalophus, E. poselgeri, E. pseudopectinatus, E. reichenbachii, E. rigidissimus, E. stramineus, E. triglochidiatus, E. viridiflorus

E. arizonicus, E. berlandieri, E. bonkerae, E. chisosensis, E. coccineus, E. dasyacanthus, 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. pectinatus var. wenigeri

Synonyms

Echinocactus pectinatus

E. viridiflorus var. davisii

Name authority

(Scheidweiler) Engelmann: in F. A. Wislizenus, Mem. Tour N. Mexico, 109. (1848)

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

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).

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Echinocereus pectinatus

Echinocereus davisii

Echinocereus pectinatus

Echinocereus davisii