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Chinese caps, western wood spurge

heartleaf sandmat

Habit Herbs, usually biennial, occasionally annual, with taproot. Herbs, annual, with taproot.
Stems

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

prostrate, occasionally mat-forming, 10–43 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.

opposite;

stipules usually distinct, occasionally connate at base, filiform, 1–1.2(–2.8) mm, usually glabrous, rarely pilose;

petiole 0.4–1 mm, usually glabrous;

blade ovate to oblong, 4.4–12 × 2.6–7.6 mm, base asymmetric, cordate to rounded, margins entire, apex rounded to mucronulate, surfaces glabrous;

only midvein conspicuous.

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.

campanulate, 1–1.3 × 1–1.3 mm, glabrous;

glands 4, yellowish to pink, elliptic, 0.3–0.5 × 0.5–1 mm;

appendages whitish to pink, sometimes drying red, elliptic to ovoid, 1.1–1.5 × 1.2–1.9 mm, distal margin entire, retuse, or erose.

Staminate flowers

11–18.

5–40.

Pistillate flowers

ovary glabrous;

styles 0.9–1.4 mm, 2-fid.

ovary glabrous;

styles 0.5–0.8 mm, 2-fid nearly entire length.

Capsules

subovoid, 2.5–3 × 3.5–4 mm, 3-lobed;

cocci rounded, smooth or puncticulate, glabrous;

columella 1.9–2.3 mm.

ovoid, 2–3 mm diam., glabrous;

columella 1.2–2.7 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.

gray or tan with dark brown mottling, ovoid, bluntly 3–4-angled in cross section, 1.8–2.1 × 1.2–1.4 mm, smooth to rugose.

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.

solitary at distal nodes;

peduncle 0.9–3 mm.

Euphorbia crenulata

Euphorbia cordifolia

Phenology Flowering and fruiting spring–summer. Flowering and fruiting summer–fall.
Habitat Conifer, oak, and mixed forests, coastal scrub, grasslands, barrens and outcrops, roadsides. Xeric oak-pine scrub, pine-barrens, sand barrens, sandy stream banks.
Elevation 30–1800 m. (100–5900 ft.) 0–200 m. (0–700 ft.)
Distribution
from FNA
CA; CO; NM; OR
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; AR; FL; GA; LA; MS; NC; OK; SC; TX
[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.)

Euphorbia cordifolia is easily identified by its cordate to rounded leaf base and distinctive filiform stipules.

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

Source FNA vol. 12, p. 301. FNA vol. 12, p. 265.
Parent taxa Euphorbiaceae > Euphorbia > subg. Esula 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. 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
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. 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. 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 Chamaesyce cordifolia
Name authority Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 192. (1859) Elliott: Sketch. Bot. S. Carolina 2: 656. (1824)
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