Euphorbia spathulata |
Euphorbia cyparissias |
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prairie spurge, reticulate seed spurge, spatulate leaf spurge, warty spurge |
cypress spurge, euphorbe cypress, graveyard spurge |
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Habit | Herbs, usually annual, rarely biennial, with taproot. | Herbs, perennial, with slender, spreading rootstock. |
Stems | erect or ascending, unbranched or branched, 10–70 cm, glabrous. |
erect or ascending, unbranched or branched, often with short axillary vegetative shoots with very narrow leaves, 10–50 cm, glabrous. |
Leaves | petiole absent or to 0.2 mm; blade oblanceolate, oblong-oblanceolate, spatulate, or cuneate, 10–50 × 6–11 mm, base broadly attenuate to rounded or shallowly cordate-clasping, margins finely serrulate (usually distally), apex usually rounded to obtuse, occasionally slightly retuse or obcordate proximally, bluntly mucronate, surfaces glabrous; venation pinnate, midvein prominent. |
petiole absent; blade linear to linear-ovate or linear-oblanceolate, 5–30 × 0.5–3 mm, base rounded to cuneate, margins entire, apex rounded to acute, surfaces glabrous; venation inconspicuous, only midvein prominent. |
Involucre | campanulate to cupulate, 0.6–1(–1.5) × 0.8–1.2 mm, glabrous; glands 4–5, elliptic, oblong, to slightly reniform, 0.2–0.6 × 0.4–1 mm; horns absent. |
campanulate to slightly urceolate, 1.5–2 × 0.9–1.1 mm, glabrous; glands 4, crescent-shaped; 0.4–0.6 × 0.7–1.3 mm; horns convergent, 0.1–0.5 mm. |
Staminate flowers | 3–10. |
15–25. |
Pistillate flowers | ovary glabrous; styles 0.8–1.5 mm, 2-fid. |
ovary glabrous; styles 1–1.2 mm, 2-fid. |
Capsules | depressed-globose, 2–3.5 × 4 mm, 3-lobed; cocci rounded, verrucose, verrucae 0.1–0.2 mm, glabrous; columella 1.4–2.2 mm. |
subglobose, 2.5–3 × 3–4 mm, slightly lobed; cocci rounded, granulate, glabrous; columella 1.9–2.1 mm. |
Seeds | red-brown to dark purple, occasionally ± glaucous, broadly ellipsoid-ovoid to nearly globose, 1.3–2.5 × 1.5–1.8 mm, smooth, reticulate, or finely low-ridged; caruncle irregularly reniform to round, subconic to lenticular, 0.3–0.4 × 0.5–0.6 mm. |
blackish, ovoid-oblong, 1.8–2.5 × 1.4–1.7 mm, smooth; caruncle nipple-shaped or subreniform, 0.2–0.4 × 0.7–1.1 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3(–5), each 1–3 times 2-branched; pleiochasial bracts broadly ovate to ovate-oblong, shorter and wider than distal leaves; dichasial bracts distinct, broadly ovate, ovate-triangular, or ovate-elliptic, base cordate-clasping or subcordate to rounded, margins serrulate, apex rounded to obtuse or acute; axillary cymose branches (0–4)5–12. |
arrangement: terminal pleiochasial branches 6–25, each 1–2-times 2-branched; pleiochasial bracts similar in shape to distal leaves except shorter and wider; dichasial bracts distinct, widely ovate, rhombic or reniform, base obtuse to truncate, margins entire, apex acute or obtuse, sometimes mucronulate; axillary cymose branches 0–15. |
Cyathia | peduncle 0.3–1(–1.5) mm. |
peduncle 0–0.5 mm. |
Euphorbia spathulata |
Euphorbia cyparissias |
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Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting spring–fall. |
Habitat | Forests, fallow fields, prairies, pastures, glades, stream banks, waste places, roadsides. | Fields, roadsides, waste places. |
Elevation | 0–3500 m. (0–11500 ft.) | 0–1500 m. (0–4900 ft.) |
Distribution |
AL; AR; AZ; CA; CO; DC; FL; GA; IA; ID; IL; IN; KS; KY; LA; MD; MI; MN; MO; MS; MT; NC; ND; NE; NM; OH; OK; OR; PA; SC; SD; TN; TX; UT; VA; WA; WI; WV; WY; ON; Mexico (Chihuahua, Sonora); s South America
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AR; CA; CO; CT; DC; DE; GA; IA; ID; IL; IN; KY; MA; MD; ME; MI; MN; MO; MT; NC; NE; NH; NJ; NY; OH; OR; PA; RI; SC; TN; UT; VA; VT; WA; WI; WV; WY; BC; MB; NB; NF; NS; ON; PE; QC; SK; Europe [Introduced in North America]
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Discussion | As treated here, Euphorbia spathulata is a wide-ranging and variable species. J. B. S. Norton (1900) recognized a number of segregates (for example, E. arkansana, E. dictyosperma, and E. obtusata) all of which are included here in a broadly defined E. spathulata. The only segregate species that has been widely recognized in regional floras is E. obtusata (for example, M. L. Fernald 1950; T. S. Cooperrider 1995; G. Yatskievych 1999–2013, vol. 2). Authors have generally distinguished the eastern North American E. obtusata from the western E. spathulata by the former's larger seeds (1.7–2.3 mm versus 1.5–1.7 mm) with smooth (versus reticulate) surfaces, larger involucres, red (versus yellow) involucral glands, and cordate-clasping (versus rounded to subcordate) dichasial bracts. Examination of specimens of E. spathulata in the broad sense from throughout North America showed that there is some geographic patterning to seed size and surface sculpturing, but the variation does not segregate cleanly into two discrete taxa. Plants from western North America typically have small seeds (1.5–1.7 mm) with reticulate surfaces, although some western individuals have seeds 1.8–1.9 mm long with reticulate surfaces. Plants from Texas generally have small seeds (1.5–1.6 mm) but with the surfaces either reticulate or completely smooth. Plants from adjacent Louisiana have small seeds with faintly reticulate to almost bumpy surfaces. Plants from eastern North America have larger seeds (2–2.3 mm) with usually smooth surfaces, although individuals from Tennessee and the Carolinas have faintly reticulate surfaces. Involucre height, gland color, and the shape of the dichasial bracts do not segregate with seed size as previous treatments have suggested. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 309. | FNA vol. 12, p. 301. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | E. arkansana, E. dictyosperma, E. obtusata, Galarhoeus arkansanus, G. obtusatus, Tithymalus arkansanus, T. dictyospermus, T. obtusatus, T. spathulatus | Galarhoeus cyparissias, Tithymalus cyparissias |
Name authority | Lamarck: in J. Lamarck et al., Encycl. 2: 428. (1788) | Linnaeus: Sp. Pl. 1: 461. (1753) |
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