Euphorbia hexagona |
Euphorbia macropus |
|
---|---|---|
six-angle spurge |
Huachuca Mountain spurge |
|
Habit | Herbs, annual, with taproot. | Herbs, perennial, with thick, globose to elongated tubers, 2–8 cm. |
Stems | erect, unbranched or branched, 30–70(–100) cm, sparsely hispid, occasionally densely so at distal nodes. |
erect to ascending, branched, 10–45(–60) cm, glabrous, puberulent, or densely hirsute to setose, often with 2-layered indumentum of long hairs intermixed with short hairs. |
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. |
usually opposite, occasionally whorled distally, or rarely with 1–2 alternate leaves; stipules 0.1–0.2 mm; petiole 0–18 mm, hirsute, sericeous, or strigose; blade linear to ovate or almost orbiculate, 6–54 × 2–19 mm, base rounded to attenuate, margins entire, occasionally ciliate with stiff recurved hairs, apex acute to obtuse, surfaces usually hirsute, sericeous, or strigose, occasionally glabrous adaxially; venation 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. |
obconic to campanulate, 1.1–1.4 × 0.5–1.5 mm, glabrous or strigillose; glands 4–5, greenish, oblong, 0.2 × 0.4–0.5 mm; appendages usually yellowish or green, rarely dark purple, ovate, flabellate, semiorbiculate, or oblong, 0.3–0.9 × 0.4–1.1 mm, usually entire. |
Staminate flowers | 15–30(–40). |
10–15. |
Pistillate flowers | ovary glabrous; styles 0.7–1.1 mm, 2-fid nearly entire length. |
ovary glabrous, sericeous, or strigillose; styles 0.4–0.6 mm, 2-fid 1/2 length. |
Capsules | subglobose to broadly ovoid, 4.7–6.5 × 4.9–6.5(–7.1) mm, glabrous; columella 3.5–4.5 mm. |
oblate, 2.3–3 × 3.1–4.2 mm, glabrous, sericeous, or strigillose; columella 1.6–2.1 mm. |
Seeds | dark brown or dark gray, ovoid, 3.4 × 2.7 mm, rugose, whitish glaucous; caruncle absent. |
black to light brown, broadly ovoid to subglobose, rounded in cross section, 1.5–2.3 × 1.4–1.8 mm, smooth or with low rounded tubercles; caruncle absent. |
Cyathia | solitary in leaf axils or in terminal cymes or dichasia; peduncle 1–2.1 mm, strigillose. |
in weakly-defined terminal dichasia; peduncle 1.4–5.8 mm, glabrous. |
Euphorbia hexagona |
Euphorbia macropus |
|
Phenology | Flowering and fruiting late summer–fall. | Flowering and fruiting summer–fall. |
Habitat | Sand prairies, other sandy soil habitats, stream banks, sand bars, damp places. | Stream banks and rocky slopes in pine-oak woodlands, sometimes with juniper, Douglas fir-pine forests. |
Elevation | 200–1300 m. (700–4300 ft.) | 1500–2200m. (4900–7200ft.) |
Distribution |
AR; CO; IA; IL; KS; MN; MO; MT; NE; NM; OK; SD; TX; WI; WY
|
AZ; Mexico; Central America (Guatemala, Honduras) |
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 macropus is a widespread and common Mexican species just barely entering the flora area in southeastern Arizona, where most of the collections are from the Huachuca Mountains. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 247. | FNA vol. 12, p. 248. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Anisophyllum macropus, E. biformis, E. plummerae | |
Name authority | Nuttall ex Sprengel: Syst. Veg. 3: 791. (1826) | (Klotzsch & Garcke) Boissier: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 15(2): 52. (1862) |
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