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Mexican fireplant, painted euphorbia

Florida pineland spurge

Habit Herbs, annual, with taproot. Herbs, perennial, with thickened rootstock.
Stems

erect-ascending, 20–100 cm, sparsely pilose to villous;

branches ± straight.

erect or ascending, 15–40 cm.

Leaves

usually alternate, occasionally opposite proximally;

petiole 10–50 mm, pilose;

blade narrowly lanceolate to elliptic or broadly obovate (then usually pandurate and 4-lobed), often polymorphic on single plants, 30–200 × 20–140 mm, base acute, margins sparsely glandular-serrulate, hirtellous, flat, apex acute to obtuse, abaxial surface sparsely appressed-pilose, adaxial surface sparsely pilosulous to glabrate;

venation pinnate, midvein prominent.

petiole absent or indistinct, blade linear to linear-elliptic or lanceolate, (25–)30–60(–115) × 1.5–14(–15) mm, chartaceous, base attenuate, apex acuminate, acute, or rounded and mucronate;

only midvein evident.

Involucre

usually campanulate, occasionally nearly hemispheric, 1.5–1.9 × 1.2–1.8 mm, glabrous;

involucral lobes divided into several linear, smooth lobes;

gland 1, yellow-green, stipitate, clavate, 1–1.4 × 1–1.2 mm, opening circular (occasionally flattened from pressing), with annular rim, glabrous;

appendages absent.

obconic or campanulate, 1.3–3.2 × 1.6–3.6 mm, lobes ovate, oblong, or nearly rectangular, 0.6–1 mm, laciniate-ciliate;

glands red to greenish, oblong or nearly circular, 0.8–1 × 1.1–2 mm, distal margins crenulate-erose, undulate, or entire.

Staminate flowers

8–15.

20–25.

Pistillate flowers

ovary glabrous or puberulent;

styles 0.8–1.3 mm, 2-fid 1/2 to nearly entire length.

gynophore exserted 2.6–6.1 mm, calyxlike lobes triangular to subulate, 0.6–1.4 mm;

styles connate 1/8 length, 1.3–2.2 mm.

Capsules

broadly ovoid, 2.8–3.8 × 4–5.3 mm, 3-lobed, usually glabrous, rarely sparsely puberulent;

columella 2.1–2.8 mm.

oblate-ovoid, 5.1–6.1 × 6.9–8.6 mm, 3-lobed;

columella 3.9–4.7 mm.

Seeds

brown-gray to ashy gray, broadly deltoid, 2.4–2.8 × 1.9–2.4 mm, angular in cross section, dorsal face strongly acute-carinate, tuberculate, with broad rounded tubercles in 2 rows;

caruncle 0.1 mm.

brown to blackish, ovoid-globose, circular or faintly 3- or 4-angled in cross section, 2.9–3.4 × 2.7–3 mm, smooth, base flattened or rounded, apex rounded or with inconspicuous blunt point.

Cyathial

arrangement: terminal dichasial branches usually 2, occasionally reduced to congested cyme, 1–2-branched (often congested and difficult to discern);

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

dichasial bracts highly reduced, rarely absent in highly congested clusters.

arrangement: terminal pleiochasial branches 2–3, 5–18 cm, 3–8 times 2-branched;

pleiochasial bracts linear-lanceolate or narrowly ovate, 25–49 × 5–9 mm, margins entire, apex acute or acuminate;

dichasial bracts ovate or lanceolate, 6–21 × 2–6 mm, margins entire, apex acute or acuminate;

axillary cymose branches 1–5.

Cyathia

peduncle 0.9–1.5 mm.

peduncle 6–24 mm (often exceeding dichasial bracts).

2n

= 28.

Euphorbia heterophylla

Euphorbia inundata

Phenology Flowering and fruiting nearly year-round.
Habitat Disturbed areas, roadsides.
Elevation 0–500 m. (0–1600 ft.)
Distribution
from USDA
Mexico; Central America; South America [Introduced, Ala., Ariz., Calif., Fla., Ga., La., Miss., N.Mex., Tex.; introduced also in Eurasia, Africa]
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; MS
[BONAP county map]
Discussion

Euphorbia heterophylla occurs from the southern United States, where it is likely naturalized, south through Mexico and Central America to South America. Because of its weediness, the precise native range in tropical and subtropical parts of the New World is not well understood. It has become widely established also in warm areas of the Old World. Leaf shape in this species is highly polymorphic within both populations and individuals. Euphorbia heterophylla can appear superficially similar to E. cyathophora but differs in its stipitate, circular involucral glands and its floral bracts that are at most very pale at the base (never colored as is typical in E. cyathophora).

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

Varieties 2 (2 in the flora).

Euphorbia inundata has a disjunct distribution in the southeastern United States. Allopatric, narrow-leaved populations from the west-central Florida peninsula are segregated as var. garrettii (E. L. Bridges and S. L. Orzell 2002).

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

Key
1. Leaf blades usually linear to narrowly elliptic or narrowly lanceolate, rarely oblanceolate, (3–)4–14(–15) mm wide, length usually 5–10(–25) times width; apex obtuse to short-acute; se Mississippi to ne Florida.
var. inundata
1. Leaf blades narrowly linear, linear, or narrowly linear-lanceolate, 1.5–3.5(–4.5) mm wide, length 15–20(–50) times width, apex short-acute to acuminate; wc Florida.
var. garrettii
Source FNA vol. 12, p. 323. FNA vol. 12, p. 314.
Parent taxa Euphorbiaceae > Euphorbia > sect. Poinsettia Euphorbiaceae > Euphorbia > sect. Nummulariopsis
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. 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. 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. 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
Subordinate taxa
E. inundata var. garrettii, E. inundata var. inundata
Synonyms E. geniculata, Poinsettia geniculata, P. heterophylla Galarhoeus inundatus
Name authority Linnaeus: Sp. Pl. 1: 453. (1753) Torrey ex Chapman: Fl. South. U.S., 402. (1860)
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