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snow-on-the-prairie

Balkan spurge, egg-leaf spurge, oblong spurge

Habit Herbs, annual, with taproot. Herbs, perennial, with woody taproot.
Stems

erect, unbranched or branched, 40–100 cm, pilose.

erect, unbranched or densely branching, 80 cm, often densely villous (especially young stems and pleiochasial branches).

Leaves

alternate;

stipules 0.3–0.4 mm;

petiole 0.3–1 mm, pilose;

blade narrowly elliptic to lanceolate, 37–54 × 7–17 mm, base cuneate to slightly rounded, margins entire, apex aristate or acute, surfaces pilose;

venation obscure, only midvein conspicuous.

petiole absent;

blade oblong to narrowly obovate or lanceolate, 15–70 × 6–25 mm, base rounded or truncate, margins finely serrulate, apex obtuse, mucronulate, surfaces glabrous;

venation inconspicuously pinnate, midvein prominent.

Involucre

campanulate, 2.7–3.5 × 2.2–3 mm, densely pilose;

glands 4–5, green to pale greenish yellow, reniform, 0.6–0.7 × 1.4–1.6 mm;

appendages white, obdeltate to orbiculate, 1.4–2.5 × 1.7–3 mm, dentate to erose.

cupulate to slightly turbinate, 1.5–2.5 × 1.3–1.5 mm, glabrous;

glands 2–3, elliptic, 0.6–0.8 × 0.8–1.2 mm;

horns absent.

Staminate flowers

30–70.

15–40.

Pistillate flowers

ovary pilose;

styles 0.7–1.2 mm, 2-fid 1/2 length.

ovary glabrous;

styles 1.5–2 mm, 2-fid.

Capsules

depressed-ovoid, 3.5–7.5 × 6–8.7 mm, densely pilose;

columella 4.5–5.5 mm.

globose, 3–4.5 × 3–4.5 mm, slightly 3-lobed;

cocci rounded, verrucose-tuberculate, glabrous;

columella 2.5–3.3 mm.

Seeds

tan to brown, ovoid, 4.3–4.5 × 3.7–3.9 mm, alveolate;

caruncle absent.

brown, ovoid, 2.4–2.6 × 1.3–2 mm, smooth, caruncle reniform, 0.2–0.3 × 0.8–0.9 mm.

Cyathia

in terminal pleiochasia dichasial and pleiochasial bracts linear to narrowly oblanceolate, with conspicuous white margins;

peduncle 1.2–3 mm, densely pilose.

peduncle 1–5 mm.

Cyathial

arrangement: terminal pleiochasial branches 3–5, each 2–3 times 2–4-branched;

pleiochasial bracts ovate, similar in size to distal leaves;

dichasial bracts distinct, ovate to suborbiculate, base truncate or rounded, margins entire or finely denticulate, apex obtuse, sometimes mucronulate;

axillary cymose branches 0–4.

Euphorbia bicolor

Euphorbia oblongata

Phenology Flowering and fruiting summer–fall. Flowering and fruiting spring–fall.
Habitat Prairies, blackland (calcareous) prairies, pastures and clearings in former blackland prairie areas, roadside clearings. Waste areas, disturbed sites, roadsides, fields, pastures.
Elevation 100–200 m. (300–700 ft.) 30–900 m. (100–3000 ft.)
Distribution
from FNA
AR; LA; OK; TX
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; OR; WA; s Europe [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

Euphorbia bicolor is similar in appearance to E. marginata but can be distinguished by its linear to narrowly oblanceolate bracts and the presence of hairs on all parts of the plant.

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

Euphorbia oblongata is listed as a noxious weed by the states of California, Oregon, and Washington.

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

Source FNA vol. 12, p. 243. FNA vol. 12, p. 305.
Parent taxa Euphorbiaceae > Euphorbia > sect. Alectoroctonum 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. 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. 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. 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 oblongatus
Name authority Engelmann & A. Gray: Boston J. Nat. Hist. 5: 233. (1845) Grisebach: Spic. Fl. Rumel. 1: 136. (1843)
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