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

urban spurge

Arizona sandmat, Arizona spurge

Habit Herbs, perennial, with slender, spreading rootstock. Herbs, annual or short-lived perennial, with slender to slightly thickened taproot.
Stems

erect or ascending, unbranched or branched, 30–90 cm, glabrous.

erect to ascending, 10–30 cm, uniformly pilose with glistening hairs.

Leaves

petiole absent;

blade oblong-elliptic, 20–65 × 9–20 mm, base truncate to auriculate, margins entire, apex obtuse to rounded, surfaces glabrous;

venation conspicuously pinnate, midvein prominent.

opposite;

stipules distinct, deltate, (0–)0.1 mm, glabrous or with few scattered hairs;

petiole 0.4–1.5 mm, pilose with glistening hairs;

blade usually ovate, rarely elliptic, 3–11 × 2–7 mm, base asymmetric, one side cuneate to rounded, other side rounded to strongly cordate, margins entire, apex obtuse or acute, surfaces pilose with glistening hairs; 3-veined from base but usually only midvein conspicuous.

Involucre

campanulate, 2.2–3 × 1.8–2 mm, glabrous;

glands 4, crescent-shaped; 0.6–1 × 1–2 mm;

horns slightly divergent to convergent, 0.1–0.2 mm.

urceolate, 1.1–1.3 × 0.5–0.9 mm, glabrous or pilose with glistening hairs;

glands 4, dark maroon, usually oblong to reniform, rarely almost circular, 0.2 × 0.2–0.4 mm;

appendages white to pink, oblong, flabellate, oblong, or elliptic, 0.3–0.6 × 0.6–0.9 mm, distal margin entire or crenulate.

Staminate flowers

15–20.

5–12.

Pistillate flowers

ovary glabrous;

styles 1.2–2 mm, 2-fid.

ovary pilose, styles 0.5–0.6 mm, 2-fid 1/2 length.

Capsules

globose, 2–2.8 × 2.2–2.7 mm, 3-lobed;

cocci rounded, smooth except finely granulate toward abaxial line, glabrous;

columella 2.1–2.7 mm.

broadly ovoid to subglobose, 1.4–1.8 mm diam., pilose;

columella 1.1–1.4 mm.

Seeds

gray or whitish, ovoid-oblong, 2–2.1 × 1.2–1.3 mm, smooth;

caruncle ± rounded and flattened, 0.8 × 0.6 mm.

gray to light brown, ovoid, 4-angled in cross section, 0.9–1.1 × 0.5–0.6 mm, rugose with 2–5 irregular transverse ridges that sometimes pass through abaxial keel.

Cyathial

arrangement: terminal pleiochasial branches 8–15, 1–2 times 2-branched;

pleiochasial bracts similar in shape but shorter and narrower than distal leaves;

dichasial bracts distinct, rhombic to reniform, base obtuse, margins entire, apex obtuse, mucronate;

axillary cymose branches 12–23.

Cyathia

peduncle 0–2 mm.

solitary at distal nodes;

peduncle 0.7–3.6 mm.

Euphorbia agraria

Euphorbia arizonica

Phenology Flowering and fruiting spring–summer. Flowering and fruiting year-round in response to sufficient moisture.
Habitat Grasslands, roadside banks, pastures. Washes and rocky slopes, sometimes on limestone, desert scrub communities often with creosote-bush, riparian forests, mesquite woodlands, oak chaparral.
Elevation 200–1600 m. (700–5200 ft.) 100–1400 m. (300–4600 ft.)
Distribution
from FNA
KS; MT; NE; NY; PA; WA; WY; AB; SK; Europe [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Euphorbia arizonica is distinctive and easily recognized by its glistening, translucent hairs that appear somewhat glutinous and are most apparent on the stems.

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

Source FNA vol. 12, p. 298. FNA vol. 12, p. 260.
Parent taxa Euphorbiaceae > Euphorbia > subg. Esula Euphorbiaceae > Euphorbia > sect. Anisophyllum
Sibling taxa
E. aaron-rossii, E. abramsiana, E. acuta, E. albomarginata, E. alta, E. angusta, E. antisyphilitica, E. arizonica, E. astyla, E. austrotexana, E. bicolor, E. bifurcata, E. bilobata, E. blodgettii, E. bombensis, E. brachycera, E. capitellata, E. carunculata, E. chaetocalyx, E. chamaesula, E. cinerascens, E. commutata, E. conferta, E. cordifolia, E. corollata, E. crenulata, E. cumulicola, E. cuphosperma, E. curtisii, E. cyathophora, E. cyparissias, E. davidii, E. deltoidea, E. dendroides, E. dentata, E. discoidalis, E. eriantha, E. exigua, E. exserta, E. exstipulata, E. falcata, E. fendleri, E. florida, E. floridana, E. garberi, E. georgiana, E. geyeri, E. glyptosperma, E. golondrina, E. gracillima, E. graminea, E. helioscopia, E. helleri, E. heterophylla, E. hexagona, E. hirta, E. hooveri, E. humistrata, E. hypericifolia, E. hyssopifolia, E. indivisa, E. innocua, E. inundata, E. ipecacuanhae, E. jaegeri, E. jejuna, E. laredana, E. lasiocarpa, E. lata, E. lathyris, E. longicruris, E. lurida, E. macropus, E. maculata, E. marginata, E. meganaesos, E. melanadenia, E. mendezii, E. mercurialina, E. mesembrianthemifolia, E. micromera, E. misera, E. missurica, E. myrsinites, E. nephradenia, E. nutans, E. oblongata, E. ocellata, E. ophthalmica, E. ouachitana, E. parishii, E. parryi, E. pediculifera, E. peplidion, E. peplus, E. perennans, E. pergamena, E. pinetorum, E. platyphyllos, E. platysperma, E. polycarpa, E. polygonifolia, E. polyphylla, E. porteriana, E. prostrata, E. pubentissima, E. purpurea, E. radians, E. rayturneri, E. revoluta, E. roemeriana, E. rosescens, E. schizoloba, E. serpens, E. serpillifolia, E. serrata, E. serrula, E. setiloba, E. simulans, E. spathulata, E. stictospora, E. strictior, E. telephioides, E. terracina, E. tetrapora, E. texana, E. theriaca, E. thymifolia, E. tithymaloides, E. trachysperma, E. trichotoma, E. vallis-mortae, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
E. aaron-rossii, E. abramsiana, E. acuta, E. agraria, E. albomarginata, E. alta, E. angusta, E. antisyphilitica, E. astyla, E. austrotexana, E. bicolor, E. bifurcata, E. bilobata, E. blodgettii, E. bombensis, E. brachycera, E. capitellata, E. carunculata, E. chaetocalyx, E. chamaesula, E. cinerascens, E. commutata, E. conferta, E. cordifolia, E. corollata, E. crenulata, E. cumulicola, E. cuphosperma, E. curtisii, E. cyathophora, E. cyparissias, E. davidii, E. deltoidea, E. dendroides, E. dentata, E. discoidalis, E. eriantha, E. exigua, E. exserta, E. exstipulata, E. falcata, E. fendleri, E. florida, E. floridana, E. garberi, E. georgiana, E. geyeri, E. glyptosperma, E. golondrina, E. gracillima, E. graminea, E. helioscopia, E. helleri, E. heterophylla, E. hexagona, E. hirta, E. hooveri, E. humistrata, E. hypericifolia, E. hyssopifolia, E. indivisa, E. innocua, E. inundata, E. ipecacuanhae, E. jaegeri, E. jejuna, E. laredana, E. lasiocarpa, E. lata, E. lathyris, E. longicruris, E. lurida, E. macropus, E. maculata, E. marginata, E. meganaesos, E. melanadenia, E. mendezii, E. mercurialina, E. mesembrianthemifolia, E. micromera, E. misera, E. missurica, E. myrsinites, E. nephradenia, E. nutans, E. oblongata, E. ocellata, E. ophthalmica, E. ouachitana, E. parishii, E. parryi, E. pediculifera, E. peplidion, E. peplus, E. perennans, E. pergamena, E. pinetorum, E. platyphyllos, E. platysperma, E. polycarpa, E. polygonifolia, E. polyphylla, E. porteriana, E. prostrata, E. pubentissima, E. purpurea, E. radians, E. rayturneri, E. revoluta, E. roemeriana, E. rosescens, E. schizoloba, E. serpens, E. serpillifolia, E. serrata, E. serrula, E. setiloba, E. simulans, E. spathulata, E. stictospora, E. strictior, E. telephioides, E. terracina, E. tetrapora, E. texana, E. theriaca, E. thymifolia, E. tithymaloides, E. trachysperma, E. trichotoma, E. vallis-mortae, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
Synonyms Tithymalus agrarius Chamaesyce arizonica
Name authority M. Bieberstein: Fl. Taur.-Caucas. 1: 375. (1808) Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. (1859)
Web links