FNA: Euphorbia pediculifera vs. Euphorbia ouachitana

	Euphorbia pediculifera	Euphorbia ouachitana
	Carrizo Mountain sandmat
Habit		Herbs, annual, with taproot.
Stems		erect-ascending, often basally decumbent, often branched near base, 12–28 cm, glabrous.
Leaves		petiole 0–3 mm; blade broadly oblanceolate to subspatulate, or proximalmost often orbiculate, 3–20 × 3–9 mm, base attenuate, margins entire, apex rounded to emarginate, surfaces glabrous; venation pinnate, midvein prominent.
Involucre		infundibular, 1.3–1.6 × 1–1.2 mm, glabrous; glands 4, crescent-shaped; 0.4–0.5 × 0.8–1 mm; horns divergent, 0.2–0.4 mm.
Staminate flowers		15–20.
Pistillate flowers		ovary glabrous; styles 0.8 mm, 2-fid.
Capsules		ovoid-globose, 2.6–2.7 × 2.5–2.7 mm, slightly lobed; cocci rounded to ± flattened, smooth, glabrous; columella 2–2.1 mm.
Seeds		dark brown, oblong-ovoid, 1.5–2 × 1–1.6 mm, with deep, rounded pits in 3–4 regular vertical rows; caruncle reniform-ovate, conic, 0.5–0.7 × 0.5–0.8 mm.
Euphorbia	pediculifera can be variable in terms of leaf shape and the extent of pubescence, but the species is readily identified by the short, appressed hairs on the leaves and the distinctive seed that is encircled by a series of round, transverse ridges.
Cyathial		arrangement: terminal pleiochasial branches 3, 1–3 times 2-branched; pleiochasial bracts ovate-deltate to subrhombic-ovate, shorter and wider than distal leaves; dichasial bracts connate 1/4 length, not imbricate, broadly deltate to subreniform, base truncate to broadly obtuse, margins entire, apex obtuse to bluntly acuminate; axillary cymose branches 1–5.
Cyathia		peduncle 0.4–0.7 mm.
2n		= 26.

	Euphorbia pediculifera	Euphorbia ouachitana
Phenology		Flowering and fruiting spring.
Habitat		Semiopen forests, bluffs and ledges, stream banks, glades.
Elevation		100–400 m. (300–1300 ft.)
Distribution	AZ; CA; nw Mexico [WildflowerSearch map] [BONAP county map]	AR; MO; OK; TN; TX
Discussion	Varieties 2 (1 in the flora). Euphorbia pediculifera var. linearifolia S. Watson is found only near Guaymas in southwestern Sonora, Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.)	Euphorbia ouachitana is restricted to semiopen forests and woodlands in the south-central United States. It is similar to E. commutata and has been most commonly identified as that species in the past. However, it differs in its consistently brown seeds that have pits in regular, vertical rows. The two species also differ in E. commutata’s numerous, proximal, long-petiolate elliptic leaves. The proximal leaves of E. ouachitana are spatulate with an orbiculate blade and petiolelike base. Aside from the restricted distribution of E. ouachitana in Missouri and Tennessee, the ranges of E. ouachitana and E. commutata do not overlap (see M. H. Mayfield 2013 for a detailed discussion of the distribution). Euphorbia ouachitana is most common in the Ouachita Mountains from southeastern Oklahoma to Hot Springs County, Arkansas. (Discussion copyrighted by Flora of North America; reprinted with permission.)
Source	FNA vol. 12, p. 281.	FNA vol. 12, p. 306.
Parent taxa	Euphorbiaceae > Euphorbia > sect. Anisophyllum	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. 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. 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
Subordinate taxa	E. pediculifera var. pediculifera
Synonyms	Chamaesyce pediculifera
Name authority	Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. (1859)	Mayfield: J. Bot. Res. Inst. Texas 7: 642, figs. 2[row 2, right], 6. (2013)
Web links	Local floras: CA Local Web sites: CalFlora, CalPhotos WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local Web sites: MO Plants WildflowerSearch iNaturalist (observations) LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Euphorbia ouachitana

Carrizo Mountain sandmat

Habit

Herbs, annual, with taproot.

Stems

erect-ascending, often basally decumbent, often branched near base, 12–28 cm, glabrous.

Leaves

petiole 0–3 mm;

blade broadly oblanceolate to subspatulate, or proximalmost often orbiculate, 3–20 × 3–9 mm, base attenuate, margins entire, apex rounded to emarginate, surfaces glabrous;

venation pinnate, midvein prominent.

Involucre

infundibular, 1.3–1.6 × 1–1.2 mm, glabrous;

glands 4, crescent-shaped; 0.4–0.5 × 0.8–1 mm;

horns divergent, 0.2–0.4 mm.

Staminate flowers

15–20.

Pistillate flowers

ovary glabrous;

styles 0.8 mm, 2-fid.

Capsules

ovoid-globose, 2.6–2.7 × 2.5–2.7 mm, slightly lobed;

cocci rounded to ± flattened, smooth, glabrous;

columella 2–2.1 mm.

Seeds

dark brown, oblong-ovoid, 1.5–2 × 1–1.6 mm, with deep, rounded pits in 3–4 regular vertical rows;

caruncle reniform-ovate, conic, 0.5–0.7 × 0.5–0.8 mm.

Euphorbia

pediculifera can be variable in terms of leaf shape and the extent of pubescence, but the species is readily identified by the short, appressed hairs on the leaves and the distinctive seed that is encircled by a series of round, transverse ridges.

Cyathial

arrangement: terminal pleiochasial branches 3, 1–3 times 2-branched;

pleiochasial bracts ovate-deltate to subrhombic-ovate, shorter and wider than distal leaves;

dichasial bracts connate 1/4 length, not imbricate, broadly deltate to subreniform, base truncate to broadly obtuse, margins entire, apex obtuse to bluntly acuminate;

axillary cymose branches 1–5.

Cyathia

peduncle 0.4–0.7 mm.

= 26.

Euphorbia pediculifera

Euphorbia ouachitana

Phenology

Flowering and fruiting spring.

Habitat

Semiopen forests, bluffs and ledges, stream banks, glades.

Elevation

100–400 m. (300–1300 ft.)

Distribution

AZ; CA; nw Mexico

[WildflowerSearch map]

[BONAP county map]

AR; MO; OK; TN; TX

Discussion

Varieties 2 (1 in the flora).

Euphorbia pediculifera var. linearifolia S. Watson is found only near Guaymas in southwestern Sonora, Mexico.

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

Euphorbia ouachitana is restricted to semiopen forests and woodlands in the south-central United States. It is similar to E. commutata and has been most commonly identified as that species in the past. However, it differs in its consistently brown seeds that have pits in regular, vertical rows. The two species also differ in E. commutata’s numerous, proximal, long-petiolate elliptic leaves. The proximal leaves of E. ouachitana are spatulate with an orbiculate blade and petiolelike base. Aside from the restricted distribution of E. ouachitana in Missouri and Tennessee, the ranges of E. ouachitana and E. commutata do not overlap (see M. H. Mayfield 2013 for a detailed discussion of the distribution). Euphorbia ouachitana is most common in the Ouachita Mountains from southeastern Oklahoma to Hot Springs County, Arkansas.

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

Source

FNA vol. 12, p. 281.

FNA vol. 12, p. 306.

Parent taxa

Euphorbiaceae > Euphorbia > sect. Anisophyllum

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. 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. 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

Subordinate taxa

E. pediculifera var. pediculifera

Synonyms

Chamaesyce pediculifera

Name authority

Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. (1859)

Mayfield: J. Bot. Res. Inst. Texas 7: 642, figs. 2[row 2, right], 6. (2013)

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).

Choose a data source: Flora of North America

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Euphorbia pediculifera

Euphorbia ouachitana

Euphorbia pediculifera

Euphorbia ouachitana