Euphorbia lathyris |
Euphorbia aaron-rossii |
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caper spurge, euphorbe épurge, gopher plant, gopher spurge, mole plant |
Marble Canyon spurge, Ross' or Marble Canyon spurge |
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Habit | Herbs, annual or biennial, with taproot. | Herbs, perennial, with deep stout rootstock. |
Stems | erect, unbranched or branched, 200 cm, glabrous, glaucous. |
erect, branched, densely clumped, previous year’s dead stems persistent, 25–45(–60) cm, glabrous, striate. |
Leaves | opposite, decussate; petiole absent; blade linear to oblong-lanceolate, 30–120 × 3–25 mm, base acute, rounded, cordate or clasping, margins entire, apex acute or subobtuse, sometimes mucronate, surfaces glabrous, abaxial ± glaucous; 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 | campanulate, 1.2–2.3 × 1.4–2.5 mm, glabrous; glands 4, elliptic, 0.3–0.6 × 1–1.3 mm; horns divergent, thick, tips rounded, dilated, 0.5–1.4 mm. |
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 | 25–30. |
20–25. |
Pistillate flowers | ovary glabrous; styles 0.7–2.2 mm, 2-fid. |
ovary strigose; styles 1–1.3 mm, 2-fid at apex. |
Capsules | depressed-globose, 9–12 × 12–16 mm, deeply 3-lobed, tardily dehiscent and appearing indehiscent, mesocarp spongy; cocci rounded, smooth, glabrous; columella 4–5.2 mm. |
subglobose, 2–3 × 4 mm, sparsely strigose; columella 2–3 mm. |
Seeds | brownish or blackish, oblong, 4.5–6 × 3–4.2 mm, rugose, irregularly reticulate; caruncle substipitate, hat-shaped, 1.6–2 × 1.2–1.5 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 2–4, each 1–2 times 2-branched; pleiochasial bracts cordate-lanceolate, shorter and wider than distal leaves; dichasial bracts distinct, ovate-oblong to lanceolate, base subcordate, margins entire, apex acute; axillary cymose branches 0–10. |
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Cyathia | peduncle 0–0.5 mm. |
in terminal monochasia (thus appearing solitary at alternate nodes); peduncle 0.5–2.5 (or 10–25) mm, glabrous or sparsely strigose. |
Euphorbia lathyris |
Euphorbia aaron-rossii |
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Phenology | Flowering and fruiting winter–fall. | Flowering and fruiting spring–fall. |
Habitat | Roadsides, cultivated fields, stream banks, waste places. | Sandy soils and dunes, occasionally rocky slopes, riparian areas. |
Elevation | 0–1800 m. (0–5900 ft.) | 600–1300 m. (2000–4300 ft.) |
Distribution |
AZ; CA; CT; ID; IL; MA; MD; MT; NC; OH; OR; PA; SC; TN; TX; VA; WA; WV; BC; ON; QC; Europe; Asia; Africa [Introduced in North America; introduced also in Mexico, South America, Australia]
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AZ |
Discussion | Euphorbia lathyris is most likely native to the central and eastern Mediterranean region, but it is widely cultivated and often locally escaped in temperate regions worldwide, as in the flora area. (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. 304. | FNA vol. 12, p. 242. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Galarhoeus lathyris, Tithymalus lathyris | |
Name authority | Linnaeus: Sp. Pl. 1: 457. (1753) — (as lathyrus) | A. H. Holmgren & N. H. Holmgren: Brittonia 40: 357, figs. 1, 2. (1988) |
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