Euphorbia helioscopia |
Euphorbia aaron-rossii |
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euphorbe réveille-matin, mad woman's milk, summer spurge, sun spurge, wart spurge, wartweed |
Marble Canyon spurge, Ross' or Marble Canyon spurge |
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Habit | Herbs, annual, with taproot. | Herbs, perennial, with deep stout rootstock. |
Stems | erect, unbranched or branched, 5–45 cm, usually glabrous or sparsely pilose. |
erect, branched, densely clumped, previous year’s dead stems persistent, 25–45(–60) cm, glabrous, striate. |
Leaves | petiole absent or to 0.5 mm; blade obovate-spatulate, 4–40 × 2–25 mm, base cuneate, attenuate, or auriculate, margins serrulate, apex rounded, surfaces glabrous; venation pinnate, midvein prominent. |
alternate, persisting, usually reflexed, occasionally spreading; stipules 0.1–0.3 mm; petiole 0.2–2.2 mm, glabrous; blade narrowly ovate to lanceolate proximally, narrowly lanceolate, linear, or filiform distally, 10–32 × 0.5–6.5 mm, base cuneate, margins entire, apex acute, surfaces pilose when young, sparsely strigose or glabrous with age; venation obscure, only midvein conspicuous. |
Involucre | cupulate, 1.5–2 × 0.7–1.1 mm, glabrous; glands 4, elliptic, 0.2–0.5 × 0.5–1 mm; horns absent. |
turbinate to campanulate, 2.2–3.7 × 1.5–2.5 mm, moderately strigose; glands 5, dark green, reniform, 0.7–1.1 × 1–1.6 mm; appendages white to pink, flabellate, 0.5–1.5 × 0.8–2.2 mm, dentate or erose. |
Staminate flowers | 10–15. |
20–25. |
Pistillate flowers | ovary glabrous; styles 0.7–1 mm, 2-fid. |
ovary strigose; styles 1–1.3 mm, 2-fid at apex. |
Capsules | depressed-globose, 2.5–4 × 3.2–4.2 mm, clearly 3-lobed; cocci rounded, smooth, glabrous; columella 0.9–1.1 mm. |
subglobose, 2–3 × 4 mm, sparsely strigose; columella 2–3 mm. |
Seeds | dark brown to blackish, subovoid, 1.6–2.2 × 1.5–1.9 mm, reticulate; caruncle elliptic, 0.9–1.1 × 0.4–0.5 mm. |
gray-green to gray-brown, globose-ovoid, 1.8–2.2 × 1.2–1.6 mm, longitudinally pitted; caruncle absent. |
Cyathial | arrangement: terminal pleiochasial branches (3–)5, each 1–2 times 2-branched; pleiochasial bracts obovate, wider than distal leaves; dichasial bracts distinct, obovate or rhombic, ± oblique, base rounded, truncate, or attenuate, margins serrulate, apex rounded; axillary cymose branches 0. |
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Cyathia | peduncle 0.2–1 mm. |
in terminal monochasia (thus appearing solitary at alternate nodes); peduncle 0.5–2.5 (or 10–25) mm, glabrous or sparsely strigose. |
Euphorbia helioscopia |
Euphorbia aaron-rossii |
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Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting spring–fall. |
Habitat | Roadsides, waste places. | Sandy soils and dunes, occasionally rocky slopes, riparian areas. |
Elevation | 0–1400 m. (0–4600 ft.) | 600–1300 m. (2000–4300 ft.) |
Distribution |
CA; CT; DC; DE; GA; ID; IL; LA; MA; MD; ME; MI; MT; NC; NH; NJ; NY; OH; OR; PA; SC; TN; TX; VA; VT; WA; WI; WY; AB; BC; NB; NF; NS; ON; PE; QC; SK; Europe; Asia; n Africa [Introduced in North America; introduced also in South America (Argentina, Chile)]
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AZ |
Discussion | Euphorbia helioscopia was collected once in Minnesota in the late 1800s but apparently did not become established there. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia aaron-rossii is restricted to the banks of the Colorado River in several small areas of the Grand and Marble canyons. The species is most closely related to E. strictior and E. wrightii, but due to its rarity, it has not been extensively studied. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 303. | FNA vol. 12, p. 242. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Galarhoeus helioscopius, Tithymalus helioscopius | |
Name authority | Linnaeus: Sp. Pl. 1: 459. (1753) | A. H. Holmgren & N. H. Holmgren: Brittonia 40: 357, figs. 1, 2. (1988) |
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