Euphorbia eriantha |
Euphorbia gracillima |
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beetle spurge |
Mexican sandmat |
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Habit | Herbs, annual or perennial, with slender to thick, woody taproot. | Herbs, annual, with slender taproot. |
Stems | erect to ascending, 10–75 cm, glabrous or with scattered appressed hairs (especially near nodes); branches arcuate. |
erect to ascending, 5–25 cm, glabrous. |
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, subulate-filiform, entire, 0.3–0.5 mm, glabrous; petiole 0.4–0.9 mm, glabrous; blade narrowly oblong to linear, often slightly falcate, 2–15 × 0.3–0.8 mm, base symmetric to subsymmetric, rounded to attenuate, margins entire, thickened and often revolute, apex acute to obtuse, surfaces glabrous; only midvein conspicuous. |
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, 0.4–0.5 × 0.4–0.6 mm, glabrous; glands 4, yellow to pink, oblong to slightly reniform, (0–)0.1–1 × 0.1–0.2 mm; appendages white to pink, ovate to oblong, 0.2–0.4 × 0.1–0.3 mm, distal margin usually entire, rarely emarginate. |
Staminate flowers | 20–25. |
5–12. |
Pistillate flowers | ovary canescent; styles 0.9–1.5 mm, unbranched. |
ovary glabrous; 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, 1.1–1.4 mm diam., glabrous; columella 0.8–1.1 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. |
orange to tan or reddish brown, narrowly ovoid, 4-angled in cross section, 0.9–1.1 × 0.5–0.6 mm, smooth. |
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 0.1–0.9 mm. |
Euphorbia eriantha |
Euphorbia gracillima |
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Phenology | Flowering and fruiting year-round in response to sufficient rainfall. | Flowering and fruiting late summer–fall. |
Habitat | Desert scrub on rocky slopes and along washes. | Rocky slopes and dry washes in desert scrub. |
Elevation | 60–800 m. (200–2600 ft.) | 600–900 m. (2000–3000 ft.) |
Distribution |
AZ; CA; NM; TX; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, San Luis Potosí, Sonora)
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AZ; Mexico (Chihuahua, Jalisco, Sinaloa, Sonora) |
Discussion | Euphorbia gracillima occurs from south-central Arizona (Pima and Pinal counties) south through northwestern Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 321. | FNA vol. 12, p. 270. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce gracillima | |
Name authority | Bentham: Bot. Voy. Sulphur, 51. (1844) | S. Watson: Proc. Amer. Acad. Arts 21: 438. (1886) |
Web links |