Euphorbia eriantha |
Euphorbia deltoidea |
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beetle spurge |
wedge sandmat |
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Habit | Herbs, annual or perennial, with slender to thick, woody taproot. | Herbs, perennial, delicate, with woody, thickened taproot, 15 mm diam.. | ||||||||||||||||
Stems | erect to ascending, 10–75 cm, glabrous or with scattered appressed hairs (especially near nodes); branches arcuate. |
prostrate, ascending, or erect, often numerous and wiry, less than 0.1 mm diam., 5–20 cm, glabrous, puberulent, canescent, villous, or hirsute, shorter hairs often uncinate and longer hairs straight or irregularly twisted. |
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Leaves | alternate; petiole 0.1–0.4 mm, often indistinct, glabrous or sparsely pilose to shortly sericeous; blade linear to linear-elliptic, 20–55 × 1–3 mm, base attenuate, margins entire or with 2–4 inconspicuous teeth near apex, apex acute, abaxial surface pilose to shortly sericeous, adaxial surface usually glabrous, rarely pilose to shortly sericeous; only midvein conspicuous. |
opposite; stipules distinct, triangular, sometimes lacerate or ciliate, 0.2–0.3 mm, glabrous or hairy; petiole 0.3–1 mm, glabrous or hairy; blade narrowly to broadly deltate, cordate, or reniform, 2–5(–7) × 1–4.5(–5) mm, base asymmetric, cordate to rounded, margins entire, ± revolute, apex obtuse or rounded, surfaces glabrous or hairy; only midvein conspicuous. |
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Involucre | obconic, 2.1–2.6 × 1.3–2 mm, canescent; involucral lobes triangular, obscured by hairs; glands (2–)4–5, green to maroon, color often obscured by hairs, sessile and broadly attached, 0.5–0.6 × 0.5–0.6 mm, opening oblong to nearly circular, densely canescent; appendages petaloid, whitish, hoodlike, incurved and covering glands, 0.5–1 × 0.5–0.8 mm, divided into 5–12 fringed, subulate segments, densely canescent. |
turbinate to campanulate, 0.8–1 × 1.1–1.3 mm, glabrous or hairy; glands 4, green to yellow-green, oblong to subcircular, 0.2–0.4 × 0.4–0.6 mm; appendages absent or white, forming narrow rim at edge of gland, rarely slightly wider than gland, (0–)0.1(–0.3) × 0.4–0.6 mm, distal margin entire. |
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Staminate flowers | 20–25. |
8–14. |
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Pistillate flowers | ovary canescent; styles 0.9–1.5 mm, unbranched. |
ovary glabrous or hairy, subtended by triangular pad of tissue; styles spreading, 0.3–0.4 mm, 2-fid 1/2 to nearly entire length. |
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Capsules | oblong to ovoid, 4.4–4.9 × 3.5–4.1 mm, canescent (often with interspersed glabrescent patches); columella 3.5–3.9 mm. |
broadly deltoid, 1.2–1.5 × 2–2.2 mm, glabrous or hairy; columella 0.9–1.3 mm. |
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Seeds | mottled black and gray or light brown, oblong or slightly ovoid, dorsiventrally compressed in cross section, 2.8–4.1 × 2–2.4 mm, irregularly pitted and tuberculate; caruncle 0.4–0.8 × 0.6–1.1 mm. |
reddish brown, ovoid, 4-angled in cross section, 0.8–1.2 × 0.5–0.6 mm, obscurely wrinkled. |
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Cyathial | arrangement: terminal cymose branches 1, 1–2-branched; pleiochasial bracts 2–3, opposite or whorled, wholly green, similar in shape and size to distal leaves; dichasial bracts similar in shape to distal leaves or often highly reduced. |
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Cyathia | peduncle 1–1.9 mm. |
solitary at distal nodes; peduncle 0.7–1.5 mm. |
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Euphorbia eriantha |
Euphorbia deltoidea |
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Phenology | Flowering and fruiting year-round in response to sufficient rainfall. | |||||||||||||||||
Habitat | Desert scrub on rocky slopes and along washes. | |||||||||||||||||
Elevation | 60–800 m. (200–2600 ft.) | |||||||||||||||||
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, San Luis Potosí, Sonora)
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FL |
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Discussion | Subspecies 4 (4 in the flora). Euphorbia deltoidea comprises four narrowly endemic subspecies, all of which are endangered due to habitat loss and fragmentation. The subspecies occur in pine rockland habitat that is free of shrubby undergrowth. Periodic fires are required to keep the rockland habitat open. Subspecies serpyllum is restricted to Big Pine Key, Monroe County, whereas the other subspecies are found only in Miami-Dade County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 321. | FNA vol. 12, p. 265. | ||||||||||||||||
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum | ||||||||||||||||
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Synonyms | Chamaesyce deltoidea | |||||||||||||||||
Name authority | Bentham: Bot. Voy. Sulphur, 51. (1844) | Engelmann ex Chapman: Fl. South. U.S. ed. 2, 647. (1883) | ||||||||||||||||
Web links |