Euphorbia chaetocalyx |
Euphorbia innocua |
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bristlecup sandmat |
velvet spurge |
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Habit | Herbs, perennial, with woody, thickened taproot. | Herbs, perennial, with moderately to strongly thickened rootstock. | ||||
Stems | usually erect, rarely slightly decumbent, often densely clustered from top of woody crown, 3–15 cm, glabrous. |
prostrate to decumbent or ascending, branched (often near base), 7–45 cm, densely pilose. |
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Leaves | opposite; stipules distinct, narrowly linear, usually entire, 0.5–1 mm, glabrous; petiole 0.5–1 mm, glabrous; blade ovate to lanceolate or oblong- or linear-lanceolate, 3–11 × 0.8–3(–5) mm, base slightly asymmetric, short-tapered, occasionally one side slightly rounded, margins entire, apex acute or short-acuminate, surfaces glabrous; only midvein conspicuous. |
alternate; stipules to 0.1 mm; petiole (0.7–)1.1–3.5 mm, pilose; blade ovate to orbiculate, 4.6–17(–25) × 4.5–15(–19) mm, base cordate, margins entire, apex rounded to obtuse, surfaces densely pilose; venation obscure, usually only midvein conspicuous. |
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Involucre | campanulate to turbinate, 0.8–1.4 × 0.8–1 mm, glabrous; glands 4, yellow-brown to reddish, concave or convex, elliptic or oval, 0.2–0.4 × 0.4–0.6 mm; appendages absent or white, lanceolate-deltate to straplike, 0.2–1.1 × 0.2–0.9 mm, distal margin entire, crenate, or deeply cleft or divided. |
campanulate, 1–1.3 × 1.2–1.4 mm, pilose; glands 4, yellow to green, elliptic, 0.2–0.3 × 0.5–0.6 mm; appendages green, elliptic, 0.4–0.5 × 0.5–0.9 mm, entire or crenulate, ciliate. |
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Staminate flowers | 25–35. |
5–10. |
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Pistillate flowers | ovary glabrous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
ovary pilose; styles 0.4–0.7 mm, 2-fid 1/2 length. |
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Capsules | depressed-ovoid to depressed-globose, 1.7–2.1 × 1.6–2.4 mm, glabrous; columella 1.2–1.8 mm. |
depressed-ovoid, 2–2.5 × 2.7–3.3 mm, pilose; columella 1.6–2.1 mm. |
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Seeds | white, ovoid-pyramidal, prominently 4-angled in cross section, 1.6–2 × 1–1.2 mm, smooth to slightly wrinkled. |
gray to brown, ovoid, 1.5–1.7 × 1.2–1.3 mm, rugose with whitish ridges; caruncle absent. |
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Cyathia | solitary at distal nodes; peduncle 0.8–1.3 mm. |
in terminal dichasia (often weakly defined); peduncle 1–2.7 mm, densely pilose. |
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Euphorbia chaetocalyx |
Euphorbia innocua |
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Phenology | Flowering and fruiting early winter–late spring. | |||||
Habitat | Sandy soils or dunes, grasslands, pastures. | |||||
Elevation | 0–20 m. (0–100 ft.) | |||||
Distribution |
AZ; NM; TX; n Mexico
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TX |
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Discussion | Varieties 2 (2 in the flora). Euphorbia chaetocalyx is similar to E. fendleri but can generally be distinguished from that species by its narrow, acute leaves and ± erect stems. Some authors have used the presence or absence and shape of the involucral gland appendages to help separate E. chaetocalyx from E. fendleri, but those characters appear highly variable and of little taxonomic utility. Some individuals from western Texas (Culberson and El Paso counties) and southern New Mexico appear intermediate with E. fendleri. The specific epithet of E. chaetocalyx refers to the bristly perianthlike segments that subtend the ovary, but these structures are found intermittently in both E. chaetocalyx and E. fendleri. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia innocua is restricted to south coastal Texas in Aransas, Calhoun, Kenedy, Kleberg, Nueces, Refugio, San Patricio, and Willacy counties. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 12, p. 263. | FNA vol. 12, p. 247. | ||||
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | E. fendleri var. chaetocalyx, Chamaesyce chaetocalyx | |||||
Name authority | (Boissier) Tidestrom: Proc. Biol. Soc. Wash. 48: 40. (1935) | L. C. Wheeler: Contr. Gray Herb. 127: 62, plate 3, fig. D. (1939) | ||||
Web links |