Euphorbia ocellata |
Euphorbia tetrapora |
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Contura Creek sandmat, Contura Creek spurge, valley spurge |
weak spurge |
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Habit | Herbs, annual, with taproot. | Herbs, annual, with taproot. | ||||
Stems | prostrate, 10–35 cm, glabrous or pilose. |
erect, unbranched, 7–20 cm, glabrous. |
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Leaves | opposite; stipules distinct, subulate, 0.5–1.6 mm, glabrous or pilose; petiole 0.3–2 mm, glabrous or pilose; blade ovate to deltate or falcate, 2.3–13 × 1.5–6 mm, base asymmetric, usually cordate, rarely rounded, margins occasionally reddish, entire, often revolute, apex acute to obtuse, occasionally mucronate, surfaces glabrous or pilose; midvein conspicuous, lateral veins frequently visible abaxially. |
petiole 1–2 mm, reduced distally; blade spatulate-cuneate, 8–10 × 4–5 mm (greatly reduced in size proximally), base cuneate, margins entire, apex rounded to emarginate or obcordate, surfaces glabrous; venation pinnate. |
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Involucre | campanulate, 1–2.5 × 1.3–2.4 mm, glabrous or pilose; glands 4, yellow becoming deep red, elliptic or oblong to orbiculate, 0.4–0.6 × 0.5–0.7 mm; appendages absent or whitish, orbiculate, 0.1–0.2 × 0.3–0.5 mm, distal margin entire. |
campanulate, 0.8–1.1 × 0.7–1 mm, glabrous; glands 4, elliptic to trapezoidal, 0.3–0.6 × 0.6–1.2 mm; horns divergent, 0.5–1 mm. |
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Staminate flowers | 30–70. |
10–15. |
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Pistillate flowers | ovary glabrous or pilose; styles 0.4–0.5 mm, 2-fid at apex. |
ovary smooth, glabrous; styles 0.6–1 mm, 2-fid. |
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Capsules | subglobose to broadly ovoid, 1.4–2.7 × 1.9–3.1 mm, glabrous or pilose; columella 1.4–2 mm. |
depressed-globose, 1.8–2.2 × 2.2–2.9 mm, slightly lobed; cocci rounded to slightly flattened, smooth, glabrous; columella 1.5–1.8 mm. |
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Seeds | whitish gray to black, ovoid to oblong, terete to bluntly subangled in cross section, 1.1–1.7 × 0.8–1.3 mm, rugose or smooth. |
reddish brown to brown, often glaucous, oblong, 1.3–1.4 × 0.8–0.9 mm, abaxial faces with 15–20 shallow pits or almost smooth, adaxial faces with 4–6 large shallow pits or irregular oblong grooves; caruncle conic, hat-shaped, 0.3–0.4 × 0.4–0.6 mm. |
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Cyathia | solitary at distal nodes; peduncle 0.9–2.2 mm. |
peduncle 0.2–0.6 mm. |
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Cyathial | arrangement: terminal pleiochasial branches 3, each 1–3(–4) times 2-branched; pleiochasial bracts obovate, similar in size to distal leaves; dichasial bracts distinct or basally subconnate, not imbricate, triangular-ovate, base truncate or cordate, margins entire, apex mucronate; axillary cymose branches 1–4. |
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Euphorbia ocellata |
Euphorbia tetrapora |
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Phenology | Flowering and fruiting spring. | |||||
Habitat | Sandy soils, dry open woods. | |||||
Elevation | 0–300 m. (0–1000 ft.) | |||||
Distribution |
AZ; CA; ID; NV; UT
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LA; OK; TX |
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Discussion | Subspecies 2 (2 in the flora). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia tetrapora is endemic to a portion of the western Gulf coastal plain. D. S. Correll and M. C. Johnston (1970) included Alabama and Georgia in the distribution of this species as well, probably due to Engelmann’s citation of a Georgia specimen from the herbarium of Samuel Boykin. Whether the Boykin specimen came from Georgia, where Boykin was based, is unclear. Because no records to support its occurrence in the eastern Gulf coastal plain (Alabama or Georgia) have been found, those states are here excluded from the distribution of E. tetrapora. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 279. | FNA vol. 12, p. 311. | ||||
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Chamaesyce ocellata | Tithymalus tetraporus | ||||
Name authority | Durand & Hilgard: Pl. Heermann., 46. (1854) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 191. (1859) | ||||
Web links |