Flora of North America species comparison

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Euphorbia helioscopia

Euphorbia schizoloba

euphorbe réveille-matin, mad woman's milk, summer spurge, sun spurge, wart spurge, wartweed

Mojave spurge
Habit Herbs, annual, with taproot. Herbs, perennial, with thick rootstock.
Stems

erect, unbranched or branched, 5–45 cm, usually glabrous or sparsely pilose.

slender, ascending, often sinuous, many, densely branched near base, 10–50 cm, usually glabrous, usually glaucous.
Leaves

petiole absent or to 0.5 mm;

blade obovate-spatulate, 4–40 × 2–25 mm, base cuneate, attenuate, or auriculate, margins serrulate, apex rounded, surfaces glabrous;

venation pinnate, midvein prominent.

petiole 0–1 mm;

blade broadly oblanceolate to obovate, 10–20 × 3–9 mm, base usually acute, occasionally short-attenuate, rarely obtuse, margins entire, apex usually acute, occasionally obtuse, acuminate to cuspidate, surfaces usually glabrous, usually glaucous;

venation pinnate, sometimes obscure, midvein prominent.
Involucre

cupulate, 1.5–2 × 0.7–1.1 mm, glabrous;

glands 4, elliptic, 0.2–0.5 × 0.5–1 mm;

horns absent.

campanulate to broadly turbinate, 2.2–3 × 2–2.5 mm, glabrous;

glands 4, irregularly semicircular to trapezoidal or elliptic-truncate, 0.8–1.5 × 1–2.2, margins strongly crenate or dentate;

horns usually absent, if present then straight, 0.1–0.2 mm, generally equaling teeth on gland margin.
Staminate flowers

10–15.

12–20.
Pistillate flowers

ovary glabrous;

styles 0.7–1 mm, 2-fid.

ovary glabrous;

styles 1–1.2 mm, 2-fid.
Capsules

depressed-globose, 2.5–4 × 3.2–4.2 mm, clearly 3-lobed;

cocci rounded, smooth, glabrous;

columella 0.9–1.1 mm.

oblong-ovoid, 3.5–4 × 3.8–5 mm, 3-lobed;

cocci rounded, smooth, glabrous;

columella 3.3–3.8 mm.
Seeds

dark brown to blackish, subovoid, 1.6–2.2 × 1.5–1.9 mm, reticulate;

caruncle elliptic, 0.9–1.1 × 0.4–0.5 mm.

gray to whitish, oblong cylindric, 2–3 × 1.5 mm, irregularly shallowly pitted to almost smooth;

caruncle conic, 0.6 × 0.6 mm.
Cyathial

arrangement: terminal pleiochasial branches (3–)5, each 1–2 times 2-branched;

pleiochasial bracts obovate, wider than distal leaves;

dichasial bracts distinct, obovate or rhombic, ± oblique, base rounded, truncate, or attenuate, margins serrulate, apex rounded;

axillary cymose branches 0.

arrangement: terminal pleiochasial branches (1–)3–4(–5), each 1–3 times 2-branched;

pleiochasial bracts broadly ovate to subcordate, usually similar in size to, occasionally wider than, distal leaves;

dichasial bracts distinct, broadly ovate to almost reniform, base obtuse, margins entire, apex obtuse, acuminate to cuspidate;

axillary cymose branches 0–2(–4).
Cyathia

peduncle 0.2–1 mm.

peduncle 0.3–1 mm.

Euphorbia helioscopia

Euphorbia schizoloba
Phenology Flowering and fruiting spring–fall. Flowering and fruiting spring–summer.
Habitat Roadsides, waste places. Desert mountains and canyon slopes, rocky and gravelly soils.
Elevation 0–1400 m. (0–4600 ft.) 500–1800 m. (1600–5900 ft.)
Distribution
from FNA
CA; CT; DC; DE; GA; ID; IL; LA; MA; MD; ME; MI; MT; NC; NH; NJ; NY; OH; OR; PA; SC; TN; TX; VA; VT; WA; WI; WY; AB; BC; NB; NF; NS; ON; PE; QC; SK; Europe; Asia; n Africa [Introduced in North America; introduced also in South America (Argentina, Chile)]
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NV
[WildflowerSearch map]
[BONAP county map]
Discussion

Euphorbia helioscopia was collected once in Minnesota in the late 1800s but apparently did not become established there.

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

Euphorbia schizoloba is a desert perennial that occurs on bluffs and ledges in the Mojave and Sonoran Deserts. Sparsely pubescent plants of E. schizoloba are known from Arizona and are best represented by several collections from the Mazatzal and Sierra Ancha mountains in Gila County from between 1000 to 1800 meters. George Engelmann published two names for this species almost simultaneously in 1861 (E. schizoloba and E. incisa). Although the authors have not been able to determine which publication has priority, Engelmann himself cited E. incisa as a synonym of E. schizoloba (in W. H. Brewer et al. 1876–1880, vol. 2), as did J. B. S. Norton (1899). Also, the type specimen at MO was annotated by Engelmann as E. schizoloba, and there is no mention of the name E. incisa on the sheet.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 12, p. 303. FNA vol. 12, p. 309.
Parent taxa Euphorbiaceae > Euphorbia > subg. Esula 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. 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. 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. 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 Galarhoeus helioscopius, Tithymalus helioscopius E. incisa, Tithymalus incisus, T. schizolobus
Name authority Linnaeus: Sp. Pl. 1: 459. (1753) Engelmann: Proc. Amer. Acad. Arts 5: 173. (1861)
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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