Flora of North America species comparison

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Euphorbia dentata

Euphorbia crenulata

green poinsettia, tooth poinsettia, tooth spurge

Chinese caps, western wood spurge
Habit Herbs, annual, with taproot. Herbs, usually biennial, occasionally annual, with taproot.
Stems

erect or ascending, 15–60 cm, both pilose and inconspicuously strigillose;

branches usually ± straight, occasionally proximal branches arcuate.

erect, sometimes decumbent at base, unbranched or branched, 12–40 cm, glabrous.
Leaves

usually opposite, occasionally alternate at distal nodes;

petiole 5–20 mm, pilose;

blade 30–70 × 4–35 mm, narrowly lanceolate to suborbiculate, usually broadest below middle, base usually acute to subobtuse, rarely subtruncate, margins coarsely crenate-dentate or doubly crenate, strigillose, flat to slightly revolute, apex broadly acute, abaxial surface long pilose with weak, filiform hairs, adaxial surface sparsely pilose to glabrate;

venation pinnate, midvein prominent.

petiole 0–2 mm;

blade obovate-spatulate to oblanceolate, 8–22 × 3–10 mm, base broadly attenuate, margins entire or slightly crisped, apex obtuse to ± rounded, minutely apiculate, surfaces glabrous;

venation pinnate, midvein prominent.
Involucre

campanulate, 3.8 × 1.8 mm, glabrous;

involucral lobes divided into several linear, smooth lobes;

glands (1–)2, green, sessile and broadly attached, 0.7–0.9 × 0.9–1.2 mm, opening oblong, glabrous;

appendages absent.

campanulate, 1.8–2.1 × 1.6–1.8 mm, glabrous;

glands 4, crescent-shaped, 0.6–1.2 × 1.5–2.3 mm;

horns slightly divergent to slightly convergent, 0.4–0.6 mm.
Staminate flowers

8–10.

11–18.
Pistillate flowers

ovary glabrous, styles 1.2 mm, 2-fid 1/2 to nearly entire length.

ovary glabrous;

styles 0.9–1.4 mm, 2-fid.
Capsules

depressed-globose, 2.5–2.8 × 3.5–4 mm, 3-lobed, glabrous;

columella 1.8–2.1 mm.

subovoid, 2.5–3 × 3.5–4 mm, 3-lobed;

cocci rounded, smooth or puncticulate, glabrous;

columella 1.9–2.3 mm.
Seeds

pale gray to black, ovoid, rounded in cross section, 2.1–2.7 × 1.7–2.1 mm, evenly minute-tuberculate;

caruncle 0.4–0.6 mm.

cream and brown mottled, oblong-ovoid to nearly globose, 2–2.5 × 1.4–1.7 mm, usually irregularly vermiculate-ridged and large-pitted, occasionally tuberculate or nearly smooth;

caruncle reniform, conic, 0.5–0.6 × 0.5–0.7 mm.
Cyathial

arrangement: terminal pleiochasial branches usually 3, occasionally reduced to congested cyme, 1–2-branched;

pleiochasial bracts 2–4, often whorled, wholly green or paler green, white, or mauve at base, similar in shape and size to distal leaves or slightly narrower;

dichasial bracts similar in shape to distal leaves but smaller (often highly reduced).

arrangement: terminal pleiochasial branches 3, each 2-branched;

pleiochasial bracts obovate to orbiculate-reniform, wider than distal leaves;

dichasial bracts usually connate 1/3–1/2 length (often only on one side), rarely only connate basally, triangular ovate to reniform, base truncate to perfoliate, margins erose-denticulate to subentire, apex rounded to obtuse, rarely apiculate;

axillary cymose branches 0–5.
Cyathia

peduncle 0.7–1 mm.

peduncle 0–0.5 mm.
2n

= 28.

Euphorbia dentata

Euphorbia crenulata
Phenology Flowering and fruiting spring–fall. Flowering and fruiting spring–summer.
Habitat Bottomland forests, stream and river banks, bluffs, prairies, glades, fallow fields, roadsides, railroad cinders, open disturbed areas. Conifer, oak, and mixed forests, coastal scrub, grasslands, barrens and outcrops, roadsides.
Elevation 0–1000 m. (0–3300 ft.) 30–1800 m. (100–5900 ft.)
Distribution
from FNA
AL; AR; GA; IA; IL; IN; KS; KY; LA; MD; MI; MO; MS; NC; NE; OH; OK; PA; SC; TN; TX; VA; WV; ON; Mexico (Chihuahua, Coahuila, Nuevo León, Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; CO; NM; OR
[WildflowerSearch map]
[BONAP county map]
Discussion

Euphorbia dentata is native from northern Mexico and the south central United States north and east through the Ohio River Valley. Scattered occurrences in the southeastern United States likely represent adventive populations. Reports of E. dentata as a noxious weed (from the United States and the Old World) should most likely be attributed to introductions of E. davidii.

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

Euphorbia crenulata is most common in the central valleys of California and southern Oregon; it occurs disjunctly in southwestern Colorado and northwestern New Mexico. Previous reports from Arizona are based on misidentified specimens. Euphorbia crenulata is closely related to E. commutata.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 12, p. 321. FNA vol. 12, p. 301.
Parent taxa Euphorbiaceae > Euphorbia > sect. Poinsettia 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. 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. 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
Synonyms Poinsettia dentata Tithymalus crenulatus
Name authority Michaux: Fl. Bor.-Amer. 2: 211. (1803) Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 192. (1859)
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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