FNA: Euphorbia crenulata

	Euphorbia crenulata
	Chinese caps, western wood spurge
Habit	Herbs, usually biennial, occasionally annual, with taproot.
Stems	erect, sometimes decumbent at base, unbranched or branched, 12–40 cm, glabrous.
Leaves	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, 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	11–18.
Pistillate flowers	ovary glabrous; styles 0.9–1.4 mm, 2-fid.
Capsules	subovoid, 2.5–3 × 3.5–4 mm, 3-lobed; cocci rounded, smooth or puncticulate, glabrous; columella 1.9–2.3 mm.
Seeds	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 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 0–0.5 mm.

	Euphorbia crenulata
Phenology	Flowering and fruiting spring–summer.
Habitat	Conifer, oak, and mixed forests, coastal scrub, grasslands, barrens and outcrops, roadsides.
Elevation	30–1800 m. (100–5900 ft.)
Distribution	CA; CO; NM; OR [WildflowerSearch map] [BONAP county map]
Discussion	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. 301.
Parent taxa	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. 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	Tithymalus crenulatus
Name authority	Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 192. (1859)
Web links	Local floras: CA, OR Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog. WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Euphorbia crenulata

Chinese caps, western wood spurge

Habit

Herbs, usually biennial, occasionally annual, with taproot.

Stems

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

Leaves

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, 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

11–18.

Pistillate flowers

ovary glabrous;

styles 0.9–1.4 mm, 2-fid.

Capsules

subovoid, 2.5–3 × 3.5–4 mm, 3-lobed;

cocci rounded, smooth or puncticulate, glabrous;

columella 1.9–2.3 mm.

Seeds

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 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 0–0.5 mm.

Euphorbia crenulata

Phenology

Flowering and fruiting spring–summer.

Habitat

Conifer, oak, and mixed forests, coastal scrub, grasslands, barrens and outcrops, roadsides.

Elevation

30–1800 m. (100–5900 ft.)

Distribution

CA; CO; NM; OR

[WildflowerSearch map]

[BONAP county map]

Discussion

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. 301.

Parent taxa

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. 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

Tithymalus crenulatus

Name authority

Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 192. (1859)

Web links

Local floras: CA, OR
Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria, Turner Photog.
WildflowerSearch
iNaturalist (observations)
USDA Plants Database
LBJ Wildflower Center
SEINet
Plants of the World Online
Encyclopedia of Life
Wikipedia
Google Image Search

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, OregonFlora

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Euphorbia crenulata

Euphorbia crenulata