FNA: Euphorbia prostrata vs. Euphorbia serrula

	Euphorbia prostrata	Euphorbia serrula
	blue weed, ground spurge, prostrate sandmat, prostrate spurge or sandmat	sawtooth sandmat
Habit	Herbs, annual, with taproot.	Herbs, annual, with slender taproot.
Stems	prostrate to decumbent, usually not mat-forming, 10–30 cm, crisped-villous to glabrate (proximally).	prostrate or ascending, 5–20 cm, usually pilose to villous, rarely glabrate.
Leaves	opposite; stipules connate (lower side) or distinct (upper side), triangular-subulate, often lacerate distally, 0.5–1 mm, short crisped-villous to glabrate; petiole 0.5–1.5 mm, usually short crisped-villous, sometimes wooly at distal nodes; blade broadly elliptic to elliptic-oblong, ovate-spatulate, or ovate, 3–11(–15) × 3–6(–8) mm, base slightly asymmetric, rounded to slightly cordate and oblique, margins serrulate at least in distal 1/2, sometimes obscurely so, apex obtuse, abaxial surface finely crisped-villous, adaxial surface usually glabrous or glabrate, sometimes sparsely crisped-villous; 3-veined from base.	opposite; stipules usually distinct, rarely connate at base, triangular or laciniate into subulate segments, 1–1.8 mm, glabrous; petiole 0.3–0.8 mm, glabrous or villous; blade oblong, ovate, or elliptic, sometimes falcate, 3–11 × 2–5 mm, base asymmetric, rounded to hemicordate, margins sharply serrate to serrulate, usually with conspicuous teeth at base of leaf, apex usually obtuse, rarely acute, surfaces frequently with red blotch in center, not papillate, sparsely pilose to glabrate; only midvein conspicuous.
Involucre	obconic, 0.6–0.9 × 0.5 mm, crisped-villous or glabrous; glands 4, reddish, oval to oblong, 0.1 × 0.1–0.2 mm; appendages white to pink, rudimentary, 0–0.2 mm, distal margin entire or irregularly scalloped.	obconic, 0.8–1.1 × 0.8–1 mm, glabrous; glands 4, greenish yellow, usually reniform to elliptic, rarely circular, 0.1 × 0.1–0.2 mm; appendages usually white, rarely light pink, orbiculate, 0.1–0.3 × 0.2–0.4 mm, distal margin entire or crenulate.
Staminate flowers	3–6.	7–15.
Pistillate flowers	ovary densely crisped-villous; styles 0.1 mm, 2-fid nearly entire length.	ovary glabrous; styles 0.3–0.5 mm, 2-fid 1/2 length.
Capsules	broadly ovoid, 1.2–2 × 1.4–1.5 mm, crisped-villous along keels and toward base, often glabrous between keels; columella 1–1.2 mm.	oblate, cocci not elongated nor terminating in empty portion, 2–2.6 × 3.2–3.7 mm, glabrous; columella 1.7–2.1 mm.
Seeds	white but with barely concealed brown surface beneath, ovoid, sharply 4-angled in cross section, abaxial faces plane to convex, adaxial faces concave, 0.8–1.1 × 0.5–0.7 mm, with several narrow, sharp, slightly irregular, transverse ridges.	white to light brown, broadly ellipsoid to ovoid, 3–4-angled in cross section, 1.5–1.8 × 1.1–1.3(–1.5) mm, smooth to minutely rugulose or with scattered small depressions.
Cyathia	solitary or in small, cymose clusters at distal nodes or on congested, axillary branches; peduncle 1–2 mm.	solitary at distal nodes; peduncle 0.4–1.8(–2.3) mm.
2n	= 18.

	Euphorbia prostrata	Euphorbia serrula
Phenology	Flowering and fruiting early spring–fall.	Flowering and fruiting spring–fall.
Habitat	Disturbed areas, fields, gardens, sidewalks, sandy places, ballast piles.	Desert scrub, with creosote bush, grasslands with mesquite and yucca, rarely in ponderosa pine woodlands, often sandy substrates.
Elevation	0–1400 m. (0–4600 ft.)	300–1900 m. (1000–6200 ft.)
Distribution	AL; AR; AZ; CA; CO; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NC; NE; NM; OH; OK; PA; SC; SD; TN; TX; UT; VA; WV; WY; Mexico; Central America; South America; West Indies [Introduced in Eurasia, Africa, Pacific Islands, Australia] [WildflowerSearch map] [BONAP county map]	AZ; NM; TX; Mexico [WildflowerSearch map] [BONAP county map]
Discussion	Euphorbia prostrata is native to tropical America and possibly into the southern part of the flora area. It is likely adventive throughout most of the northern part of its range. It is widely naturalized throughout much of the rest of the tropics. (Discussion copyrighted by Flora of North America; reprinted with permission.)	In Mexico, Euphorbia serrula is found from Chihuahua and Coahuila south to Puebla. (Discussion copyrighted by Flora of North America; reprinted with permission.)
Source	FNA vol. 12, p. 285.	FNA vol. 12, p. 288.
Parent taxa	Euphorbiaceae > Euphorbia > sect. Anisophyllum	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. 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. 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. schizoloba, E. serpens, E. serpillifolia, E. serrata, 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 prostrata	Chamaesyce serrula
Name authority	Aiton: Hort. Kew. 2: 139. (1789)	Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 188. (1859)
Web links	Local floras: CA Local Web sites: CalFlora, CalPhotos, Go Botany, IL Wildflowers, KS Wildflowers, LA Plants, MD Biodiversity, MI Flora, MO Plants WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Euphorbia serrula

blue weed, ground spurge, prostrate sandmat, prostrate spurge or sandmat

sawtooth sandmat

Habit

Herbs, annual, with taproot.

Herbs, annual, with slender taproot.

Stems

prostrate to decumbent, usually not mat-forming, 10–30 cm, crisped-villous to glabrate (proximally).

prostrate or ascending, 5–20 cm, usually pilose to villous, rarely glabrate.

Leaves

opposite;

stipules connate (lower side) or distinct (upper side), triangular-subulate, often lacerate distally, 0.5–1 mm, short crisped-villous to glabrate;

petiole 0.5–1.5 mm, usually short crisped-villous, sometimes wooly at distal nodes;

blade broadly elliptic to elliptic-oblong, ovate-spatulate, or ovate, 3–11(–15) × 3–6(–8) mm, base slightly asymmetric, rounded to slightly cordate and oblique, margins serrulate at least in distal 1/2, sometimes obscurely so, apex obtuse, abaxial surface finely crisped-villous, adaxial surface usually glabrous or glabrate, sometimes sparsely crisped-villous; 3-veined from base.

opposite;

stipules usually distinct, rarely connate at base, triangular or laciniate into subulate segments, 1–1.8 mm, glabrous;

petiole 0.3–0.8 mm, glabrous or villous;

blade oblong, ovate, or elliptic, sometimes falcate, 3–11 × 2–5 mm, base asymmetric, rounded to hemicordate, margins sharply serrate to serrulate, usually with conspicuous teeth at base of leaf, apex usually obtuse, rarely acute, surfaces frequently with red blotch in center, not papillate, sparsely pilose to glabrate;

only midvein conspicuous.

Involucre

obconic, 0.6–0.9 × 0.5 mm, crisped-villous or glabrous;

glands 4, reddish, oval to oblong, 0.1 × 0.1–0.2 mm;

appendages white to pink, rudimentary, 0–0.2 mm, distal margin entire or irregularly scalloped.

obconic, 0.8–1.1 × 0.8–1 mm, glabrous;

glands 4, greenish yellow, usually reniform to elliptic, rarely circular, 0.1 × 0.1–0.2 mm;

appendages usually white, rarely light pink, orbiculate, 0.1–0.3 × 0.2–0.4 mm, distal margin entire or crenulate.

Staminate flowers

3–6.

7–15.

Pistillate flowers

ovary densely crisped-villous;

styles 0.1 mm, 2-fid nearly entire length.

ovary glabrous;

styles 0.3–0.5 mm, 2-fid 1/2 length.

Capsules

broadly ovoid, 1.2–2 × 1.4–1.5 mm, crisped-villous along keels and toward base, often glabrous between keels;

columella 1–1.2 mm.

oblate, cocci not elongated nor terminating in empty portion, 2–2.6 × 3.2–3.7 mm, glabrous;

columella 1.7–2.1 mm.

Seeds

white but with barely concealed brown surface beneath, ovoid, sharply 4-angled in cross section, abaxial faces plane to convex, adaxial faces concave, 0.8–1.1 × 0.5–0.7 mm, with several narrow, sharp, slightly irregular, transverse ridges.

white to light brown, broadly ellipsoid to ovoid, 3–4-angled in cross section, 1.5–1.8 × 1.1–1.3(–1.5) mm, smooth to minutely rugulose or with scattered small depressions.

Cyathia

solitary or in small, cymose clusters at distal nodes or on congested, axillary branches;

peduncle 1–2 mm.

solitary at distal nodes;

peduncle 0.4–1.8(–2.3) mm.

= 18.

Euphorbia prostrata

Euphorbia serrula

Phenology

Flowering and fruiting early spring–fall.

Flowering and fruiting spring–fall.

Habitat

Disturbed areas, fields, gardens, sidewalks, sandy places, ballast piles.

Desert scrub, with creosote bush, grasslands with mesquite and yucca, rarely in ponderosa pine woodlands, often sandy substrates.

Elevation

0–1400 m. (0–4600 ft.)

300–1900 m. (1000–6200 ft.)

Distribution

AL; AR; AZ; CA; CO; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NC; NE; NM; OH; OK; PA; SC; SD; TN; TX; UT; VA; WV; WY; Mexico; Central America; South America; West Indies [Introduced in Eurasia, Africa, Pacific Islands, Australia]

[WildflowerSearch map]

[BONAP county map]

AZ; NM; TX; Mexico

[WildflowerSearch map]

[BONAP county map]

Discussion

Euphorbia prostrata is native to tropical America and possibly into the southern part of the flora area. It is likely adventive throughout most of the northern part of its range. It is widely naturalized throughout much of the rest of the tropics.

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

In Mexico, Euphorbia serrula is found from Chihuahua and Coahuila south to Puebla.

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

Source

FNA vol. 12, p. 285.

FNA vol. 12, p. 288.

Parent taxa

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. 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. 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. schizoloba, E. serpens, E. serpillifolia, E. serrata, 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 prostrata

Chamaesyce serrula

Name authority

Aiton: Hort. Kew. 2: 139. (1789)

Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 188. (1859)

Web links

Local floras: CA
Local Web sites: CalFlora, CalPhotos, Go Botany, IL Wildflowers, KS Wildflowers, LA Plants, MD Biodiversity, MI Flora, MO Plants
WildflowerSearch
iNaturalist (observations)
USDA Plants Database
LBJ Wildflower Center
SEINet
Plants of the World Online
Encyclopedia of Life
Wikipedia
Google Image Search

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Euphorbia prostrata

Euphorbia serrula

Euphorbia prostrata

Euphorbia serrula