Euphorbia hexagona |
Euphorbia astyla |
|
---|---|---|
six-angle spurge |
alkali spurge, Pecos spurge |
|
Habit | Herbs, annual, with taproot. | Herbs, perennial, with woody or fibrous-fleshy taproot, 5–12 mm thick. |
Stems | erect, unbranched or branched, 30–70(–100) cm, sparsely hispid, occasionally densely so at distal nodes. |
decumbent, ascending, or erect, few to many emerging from woody crown, 5–25(–50) cm, glabrous. |
Leaves | 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. |
opposite; stipules connate into deltate scale, 0.2–0.5 mm, minutely lacerate at apex, glabrous; petiole 0–0.2(–0.3) mm, glabrous; blade orbiculate-reniform to acute-cordate, 2–5(–8) × 2–5(–6) mm, base ± asymmetric, cordate to auriculate, sometimes clasping stem, margins entire, apex narrowly acute, surfaces glabrous; 2- or 3-veined from base, but usually only midvein conspicuous. |
Involucre | 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. |
broadly campanulate, 0.8–1.4 × 0.9–1.4 mm, glabrous; glands 4, yellow-green to brownish, oblong, 0.2–0.3 × 0.5–0.7 mm; appendages white, flabellate to oblong, 0.1–0.2(–0.5) × 0.4–0.8 mm, distal margin entire or dentate-crenate. |
Staminate flowers | 15–30(–40). |
22–26. |
Pistillate flowers | ovary glabrous; styles 0.7–1.1 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.3–0.4 mm, unbranched, thickened-clavate. |
Capsules | subglobose to broadly ovoid, 4.7–6.5 × 4.9–6.5(–7.1) mm, glabrous; columella 3.5–4.5 mm. |
ovoid and broadly triangular, 1.5–1.9(–2.5) × 1.4–1.6(–2.2) mm, glabrous; columella 1.2–1.8 mm. |
Seeds | dark brown or dark gray, ovoid, 3.4 × 2.7 mm, rugose, whitish glaucous; caruncle absent. |
white, oblong, 4-angled in cross section, adaxial faces slightly concave, with long raphe between, 1.5–1.8 × 0.7–1 mm, markedly foveolate, with irregular to ± parallel or anastomosing ridges. |
Cyathia | solitary in leaf axils or in terminal cymes or dichasia; peduncle 1–2.1 mm, strigillose. |
solitary at distal nodes; peduncle 0.3–1(–1.5) mm. |
2n | = 28. |
|
Euphorbia hexagona |
Euphorbia astyla |
|
Phenology | Flowering and fruiting late summer–fall. | Flowering and fruiting late spring–early fall. |
Habitat | Sand prairies, other sandy soil habitats, stream banks, sand bars, damp places. | Desert, grasslands, limestone substrates, usually on very saline or alkaline soils. |
Elevation | 200–1300 m. (700–4300 ft.) | 700–1100 m. (2300–3600 ft.) |
Distribution |
AR; CO; IA; IL; KS; MN; MO; MT; NE; NM; OK; SD; TX; WI; WY
|
TX; Mexico (Coahuila, Nuevo León) |
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.) |
Euphorbia astyla is a specialist on halophytic, alkaline soils and is known in the flora area only in part of Pecos County. The species is closely related to E. jejuna but differs in its sessile or sub-sessile leaves with a cordate-auriculate base and involucral gland appendages that are not deeply lobed or cleft. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 247. | FNA vol. 12, p. 261. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce astyla | |
Name authority | Nuttall ex Sprengel: Syst. Veg. 3: 791. (1826) | Engelmann ex Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 40. (1862) |
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