Flora of North America species comparison

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Euphorbia marginata

Euphorbia hooveri

euphorbe marginée, mountain snow spurge, smoke-on-the-prairie, snow-on-the-mountain, variegated spurge, whitemargined spurge

Hoover's sandmat, Hoover's spurge
Habit Herbs, annual, with taproot. Herbs, annual, with slender to slightly thickened taproot.
Stems

erect, unbranched or branched, 30–85(–150) cm, pilose or glabrous.

prostrate, occasionally mat-forming, 4–10 cm, glabrous.
Leaves

alternate;

stipules 0.1–0.3 mm;

petiole 0.2–3 mm, glabrous or minutely pilose;

blade broadly ovate to elliptic, 32–62(–82) × 18–28(–52) mm, base rounded to cuneate, margins entire, often white on distal leaves, apex acute, rarely mucronate, surfaces glabrous;

venation obscure, only midvein conspicuous.

opposite;

stipules distinct or connate at base, deeply laciniate into numerous subulate to filiform segments, 0.3–1.3 mm, glabrous;

petiole 0–0.5 mm, glabrous;

blade broadly ovate, broadly oblong or suborbiculate, 3–7 × 2–5.5 mm, base asymmetric, hemiamplexicaulous, margin sharply serrulate to denticulate, teeth whitish and occasionally setaelike at apex, apex obtuse, surfaces papillate, glabrous; 3-veined from base, usually only midvein conspicuous.
Involucre

campanulate, 2.2–3.5 × 1.3–2.3 mm, margin between glands deeply divided into fringe of fimbriate lobes, pilose;

glands 4–5, green to greenish yellow, reniform to subcircular, 0.7–1.1 × 1–1.6 mm;

appendages white, orbiculate, 1.5–2.7 × 1.9–2.9(–3.6) mm, entire.

campanulate, 1.2–1.5 × 1.5–2.2 mm, papillate;

glands 4, yellow to reddish, subcircular to oblong, 0.4–0.5 × 0.5–0.7 mm;

appendages white to pink, 0.3–0.9 × 0.7–1.6 mm, divided into 4–6 narrowly triangular, acute segments, these occasionally 2-fid, margins entire.
Staminate flowers

30–70.

25–35.
Pistillate flowers

ovary pilose;

styles 1–2.5 mm, 2-fid 1/2–2/3 length.

ovary glabrous;

styles 1.8–2.6 mm, unbranched, filiform.
Capsules

oblate, 3–5 × 3.5–7.5 mm, moderately to densely pilose;

columella 3–4.1 mm.

oblate, 1.5–1.7 × 1.8–2.2 mm, glabrous;

columella 1.2–1.4 mm.
Seeds

orange-tan to gray, ovoid, 3.7–3.9 × 3–3.3 mm, rugose, with 2 transverse ridges (one dark orange to brown, other inconspicuous);

caruncle absent.

gray to light brown, ovoid, inconspicuously 4-angled in cross section, 1.2–1.6 × 1–1.1 mm, rugose.
Cyathia

in terminal pleiochasia, dichasial bracts narrowly elliptic to oblanceolate with conspicuous white margins;

peduncle 1.8–2.7(–22) mm, densely pilose.

solitary at distal nodes;

peduncle 0.5 mm, stout.
2n

= 56.

Euphorbia marginata

Euphorbia hooveri
Phenology Flowering and fruiting summer–fall. Flowering and fruiting summer–fall.
Habitat Disturbed areas and grasslands. Drying mudflats of vernal pools in grasslands and woodlands.
Elevation 0–1700 m. (0–5600 ft.) 20–200 m. (100–700 ft.)
Distribution
from FNA
AR; CA; CO; CT; IA; IL; IN; KS; LA; MA; MD; MI; MN; MO; MT; NC; NE; NH; NM; NY; OH; OK; PA; RI; SC; SD; TN; TX; UT; VA; WI; WV; WY; MB; ON; QC; SK; c Mexico; s Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Euphorbia marginata is native to the central United States. The type specimen was collected by Meriwether Lewis along the Yellowstone River in southern Montana in 1806, and it has been reported to be native as far south as Arizona, New Mexico, and Texas, and as far east as southern Minnesota, western Iowa, and Missouri (G. Yatskievych 1999–2013, vol. 2). It is presumably naturalized outside of this area. Euphorbia marginata is widely cultivated as an ornamental for its showy, white-margined distal leaves, and it can escape locally.

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

Euphorbia hooveri is federally listed as threatened; its populations are being affected severely by habitat loss and the invasion of exotic species. The species is endemic to vernal pools in six counties in the Central Valley of California. Molecular data show that E. hooveri is a hybrid species, closely related to E. albomarginata and E. serpens (Y. Yang and P. E. Berry 2011).

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 12, p. 248. FNA vol. 12, p. 271.
Parent taxa Euphorbiaceae > Euphorbia > sect. Alectoroctonum Euphorbiaceae > Euphorbia > sect. Anisophyllum
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. 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. 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 E. bonplandii, Lepadena marginata Chamaesyce hooveri
Name authority Pursh: Fl. Amer. Sept. 2: 607. (1813) L. C. Wheeler: Proc. Biol. Soc. Wash. 53: 9. (1940)
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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