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Arizona sandmat, Arizona spurge

greater Florida spurge

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

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

erect, 20–65 cm.

Leaves

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.

petiole absent;

blade linear to linear-elliptic or linear-lanceolate, 30–105 × 2–4(–7) mm, chartaceous, base attenuate, rounded, or nearly truncate, apex acute;

only midvein evident.

Involucre

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.

campanulate or obconic, 1.6–3.3 × 1.8–3.1 mm, lobes ovate, 0.5–0.7 mm, ciliate, exceeded by glands;

glands yellow-green, oblong to trapezoidal, 0.5–0.8 × 0.8–1.2 mm, distal margins deeply erose.

Staminate flowers

5–12.

20.

Pistillate flowers

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

gynophore exserted 2.9–5.3 mm, calyxlike lobes triangular, 0.3–0.7 mm;

styles connate 1/3–1/4 length, 1.1–1.7 mm.

Capsules

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

columella 1.1–1.4 mm.

oblate-ovoid, 4.6–5.5 × 8.9–9 mm, strongly 3-lobed;

columella 3.4–4.2 mm.

Seeds

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.

brown to blackish, depressed-globose, circular in cross section, 2.8–3 × 3.2–3.6 mm, smooth, base flattened, with punctiform depressions, apex flattened.

Cyathia

solitary at distal nodes;

peduncle 0.7–3.6 mm.

peduncle (except for that of 1st cyathium at base of pleiochasia) 2–5 mm (not exceeding dichasial bracts).

Cyathial

arrangement: terminal pleiochasial branches 3–5, 3–16 cm, 3–5(–7) times 2-branched;

pleiochasial bracts linear-lanceolate or narrowly ovate, 19–55 × 4–12 mm, margins entire, apex acute or acuminate;

dichasial bracts usually ovate, lanceolate, or oblong, rarely deltate, 8–21 × 4–14 mm, margins entire, apex acute, acuminate, or rounded with mucronate tip;

axillary cymose branches 1–3(–6).

Euphorbia arizonica

Euphorbia floridana

Phenology Flowering and fruiting year-round in response to sufficient moisture. Flowering and fruiting spring–fall.
Habitat Washes and rocky slopes, sometimes on limestone, desert scrub communities often with creosote-bush, riparian forests, mesquite woodlands, oak chaparral. Xeric pine-oak sandhills, pine scrub, sandy soils.
Elevation 100–1400 m. (300–4600 ft.) 20–80 m. (100–300 ft.)
Distribution
from FNA
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Sonora)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA
[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. 260. FNA vol. 12, p. 314.
Parent taxa Euphorbiaceae > Euphorbia > sect. Anisophyllum Euphorbiaceae > Euphorbia > sect. Nummulariopsis
Sibling taxa
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
E. aaron-rossii, E. abramsiana, E. acuta, E. agraria, 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. 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 Chamaesyce arizonica Galarhoeus floridanus
Name authority Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. (1859) Chapman: Fl. South. U.S., 401. (1860)
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