Euphorbia eriantha |
Euphorbia laredana |
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beetle spurge |
Laredo sandmat |
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Habit | Herbs, annual or perennial, with slender to thick, woody taproot. | Herbs, annual, with taproot. |
Stems | erect to ascending, 10–75 cm, glabrous or with scattered appressed hairs (especially near nodes); branches arcuate. |
prostrate, ± mat-forming, 10–20 cm, densely ashy pilose-tomentose. |
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, filiform, 0.5–1 mm, pilose-tomentose; petiole 0.5–1 mm, pilose-tomentose; blade ovate to elliptic-oblong, 3–6 × 3–5 mm, base markedly asymmetric, rounded to slightly auriculate, margins usually entire, rarely largest leaves sparsely serrulate, apex acute to obtuse, surfaces moderately to densely strigose; 3-veined from base. |
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. |
obconic, 0.6–1 × 0.5–1 mm, densely strigose; glands 4, yellowish to reddish, oval to oblong, 0.1 × 0.2–0.3 mm; appendages white to pink, rudimentary or minute, (0–)0.1–0.2 × (0–)0.1–0.3 mm, distal margin crenulate. |
Staminate flowers | 20–25. |
3–5. |
Pistillate flowers | ovary canescent; styles 0.9–1.5 mm, unbranched. |
ovary densely white villous; styles 0.1–0.2 mm, 2-fid 1/2 length. |
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 ovoid, 1.3–1.5 × 1.4–1.5 mm, villous on keels, often glabrous or less hairy between keels; columella 1.1–1.3 mm. |
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. |
white, barely concealing brown undercoat, 4-angled, sharply angled in cross section, abaxial faces plane to convex, adaxial faces concave, 1.1–1.2 × 0.5–0.7 mm, with several rounded, irregular, transverse ridges. |
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 or in small, cymose clusters at distal nodes or on congested, axillary branches; peduncle 0.5–1.5 mm. |
Euphorbia eriantha |
Euphorbia laredana |
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Phenology | Flowering and fruiting year-round in response to sufficient rainfall. | Flowering and fruiting almost year-round. |
Habitat | Desert scrub on rocky slopes and along washes. | Open sandy, loamy, or gravelly sites, old dunes, pastures. |
Elevation | 60–800 m. (200–2600 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, San Luis Potosí, Sonora)
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TX; Mexico (Tamaulipas) |
Discussion | Euphorbia laredana is similar to E. prostrata but differs from that species in its more densely tomentose indumentum, leaves with usually entire rather than serrulate margins, and slightly longer seeds with rounded rather than sharp ridges. The species occurs primarily in southern Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 321. | FNA vol. 12, p. 274. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce laredana | |
Name authority | Bentham: Bot. Voy. Sulphur, 51. (1844) | Millspaugh: Pittonia 2: 88. (1890) |
Web links |