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sun spurge

cypress spurge, euphorbe cypress, graveyard spurge

Habit Herbs, perennial, with moniliform tuberous rootstock. Herbs, perennial, with slender, spreading rootstock.
Stems

erect, 5–20(–30) cm, usually glabrous, occasionally puberulent;

branches ± straight.

erect or ascending, unbranched or branched, often with short axillary vegetative shoots with very narrow leaves, 10–50 cm, glabrous.

Leaves

alternate;

petiole 0–2 mm, glabrous or strigose;

blade linear-lanceolate to ovate or broadly elliptic, 25–50 × 3–20 mm, unlobed, base rounded (tapered to petiole), margins with few glandular teeth, strigillose, flat to revolute, apex acute, abaxial surface coarsely strigose, adaxial surface strigose-hirsute;

venation pinnate, midvein prominent.

petiole absent;

blade linear to linear-ovate or linear-oblanceolate, 5–30 × 0.5–3 mm, base rounded to cuneate, margins entire, apex rounded to acute, surfaces glabrous;

venation inconspicuous, only midvein prominent.

Involucre

broadly globose-cupulate, 1.7–2.1 × 2.2–2.5 mm, glabrous or puberulent;

involucral lobes divided into triangular segments;

glands 1–4(–5), white, sessile and broadly attached, 1.1 × 1.4 mm, opening oblong, glabrous;

appendages absent.

campanulate to slightly urceolate, 1.5–2 × 0.9–1.1 mm, glabrous;

glands 4, crescent-shaped; 0.4–0.6 × 0.7–1.3 mm;

horns convergent, 0.1–0.5 mm.

Staminate flowers

20–25.

15–25.

Pistillate flowers

ovary glabrous or puberulent, styles 3–4 mm, 2-fid 1/2 to nearly entire length.

ovary glabrous;

styles 1–1.2 mm, 2-fid.

Capsules

depressed-globose, 3.8–5 × 4–5 mm, 3-lobed, glabrous or puberulent;

columella 3.6–4.5 mm.

subglobose, 2.5–3 × 3–4 mm, slightly lobed;

cocci rounded, granulate, glabrous;

columella 1.9–2.1 mm.

Seeds

white, mottled brown to gray, ellipsoid, rounded in cross section, 4–4.6 × 2.4–3.2 mm, smoothly and broadly pitted or grooved;

caruncle 0.1 mm.

blackish, ovoid-oblong, 1.8–2.5 × 1.4–1.7 mm, smooth;

caruncle nipple-shaped or subreniform, 0.2–0.4 × 0.7–1.1 mm.

Cyathial

arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched (often highly condensed);

pleiochasial bracts 6–8(–10), as tight involucrate whorl, wholly white to pale pink or red, usually narrower than distal leaves;

dichasial bracts linear and highly reduced.

arrangement: terminal pleiochasial branches 6–25, each 1–2-times 2-branched;

pleiochasial bracts similar in shape to distal leaves except shorter and wider;

dichasial bracts distinct, widely ovate, rhombic or reniform, base obtuse to truncate, margins entire, apex acute or obtuse, sometimes mucronulate;

axillary cymose branches 0–15.

Cyathia

peduncle 2–5.5 mm.

peduncle 0–0.5 mm.

Euphorbia radians

Euphorbia cyparissias

Phenology Flowering and fruiting spring–summer. Flowering and fruiting spring–fall.
Habitat Pinyon-juniper woodlands, oak savannas, desert grasslands and scrub. Fields, roadsides, waste places.
Elevation 700–2500 m. (2300–8200 ft.) 0–1500 m. (0–4900 ft.)
Distribution
from FNA
AZ; TX; Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AR; CA; CO; CT; DC; DE; GA; IA; ID; IL; IN; KY; MA; MD; ME; MI; MN; MO; MT; NC; NE; NH; NJ; NY; OH; OR; PA; RI; SC; TN; UT; VA; VT; WA; WI; WV; WY; BC; MB; NB; NF; NS; ON; PE; QC; SK; Europe [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

Euphorbia radians is widely distributed but scattered from the Sonoran and Chihuahuan deserts south to Oaxaca in Mexico. The species is distinct among species in sect. Poinsettia in the flora area in its precocious habit, often flowering before the leaves emerge.

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

Source FNA vol. 12, p. 324. FNA vol. 12, p. 301.
Parent taxa Euphorbiaceae > Euphorbia > sect. Poinsettia Euphorbiaceae > Euphorbia > subg. Esula
Sibling taxa
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. 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. 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. 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 Poinsettia radians Galarhoeus cyparissias, Tithymalus cyparissias
Name authority Bentham: Pl. Hartw., 8. (1839) Linnaeus: Sp. Pl. 1: 461. (1753)
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