Euphorbia cuphosperma |
Euphorbia hexagona |
|
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hairy-fruit spurge |
six-angle spurge |
|
Habit | Herbs, annual, with taproot. | Herbs, annual, with taproot. |
Stems | erect, 13–20 cm, both pilose to villous and densely strigillose; branches ± straight. |
erect, unbranched or branched, 30–70(–100) cm, sparsely hispid, occasionally densely so at distal nodes. |
Leaves | usually opposite, occasionally alternate at distal nodes; petiole 3–15 mm, pilose; blade narrowly to broadly elliptic, or lanceolate to ovate, 30–80 × 10–15 mm, base cuneate to rounded, margins coarsely crenate-dentate, strigose, revolute to nearly flat, apex broadly acute to acuminate, or obtuse, abaxial surface pilose, adaxial surface sparsely strigose-hirsute; venation pinnate, midvein prominent. |
opposite; stipules (0–)0.1 mm; petiole 1–4 mm, pilose; blade linear-filiform, linear, or elliptic, 21–40 × 0.9–7.5 mm, base attenuate, margins entire, apex acute, abaxial surface sparsely hispidulous to strigillose, adaxial surface glabrous; venation obscure, only midvein conspicuous. |
Involucre | campanulate to slightly cylindric, 2.3 × 1.2 mm, glabrous; involucral lobes divided into several linear, smooth lobes; gland 1, yellow-green, stipitate, clavate, 1–1.2 × 0.8–0.9 mm, opening bilabiate and oblong, glabrous; appendages absent. |
campanulate, 1–1.5 × (1–)1.5–1.8 mm, hispid; glands 5, green to deep red, elliptic to reniform, 0.5 × 0.8–1 mm; appendages white to green, tinged red, deltate to ovate, 0.7–1.7 × (0.9–)1.3–1.5 mm, entire. |
Staminate flowers | 3–5. |
15–30(–40). |
Pistillate flowers | ovary pilose; styles 1.2 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.7–1.1 mm, 2-fid nearly entire length. |
Capsules | broadly ovoid, 2.2–3 × 1.9–2.7 mm, 3-lobed, pilose; columella 2–2.4 mm. |
subglobose to broadly ovoid, 4.7–6.5 × 4.9–6.5(–7.1) mm, glabrous; columella 3.5–4.5 mm. |
Seeds | gray-brown to pale gray, pyramidally ovoid, angular in cross section, 2.3–2.6 × 2.4–2.6 mm, coarsely tuberculate, tubercles in 2 transverse rows; caruncle 0.2–0.4 mm. |
dark brown or dark gray, ovoid, 3.4 × 2.7 mm, rugose, whitish glaucous; caruncle absent. |
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 at base, similar in shape and size to distal leaves or slightly narrower; dichasial bracts highly reduced. |
|
Cyathia | peduncle 0.5–0.8 mm. |
solitary in leaf axils or in terminal cymes or dichasia; peduncle 1–2.1 mm, strigillose. |
2n | = 56. |
|
Euphorbia cuphosperma |
Euphorbia hexagona |
|
Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting late summer–fall. |
Habitat | Open montane and canyon forests, pinyon-juniper forests, montane grasslands, stream beds, disturbed habitats. | Sand prairies, other sandy soil habitats, stream banks, sand bars, damp places. |
Elevation | 800–2000 m. (2600–6600 ft.) | 200–1300 m. (700–4300 ft.) |
Distribution |
AZ; NM; Mexico; Central America (Guatemala)
|
AR; CO; IA; IL; KS; MN; MO; MT; NE; NM; OK; SD; TX; WI; WY
|
Discussion | Euphorbia hexagona is native to the central United States and is most common from southern South Dakota to Oklahoma and northern Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 319. | FNA vol. 12, p. 247. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | E. dentata var. cuphosperma, Poinsettia cuphosperma | |
Name authority | (Engelmann) Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 73. (1862) | Nuttall ex Sprengel: Syst. Veg. 3: 791. (1826) |
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