Euphorbia hypericifolia |
Euphorbia hooveri |
|
---|---|---|
graceful sandmat, graceful spurge |
Hoover's sandmat, Hoover's spurge |
|
Habit | Herbs, annual, with taproot. | Herbs, annual, with slender to slightly thickened taproot. |
Stems | erect to ascending, 15–50 cm, glabrous. |
prostrate, occasionally mat-forming, 4–10 cm, glabrous. |
Leaves | opposite; stipules connate, deltate, usually entire, sometimes laciniate-fringed at tip, 1.5–2.2 mm, glabrous; petiole 1–3 mm, glabrous; blade obliquely oblong-oblanceolate, 10–35 × 7–15 mm, base asymmetric, oblique, margins serrate or serrulate, especially toward apex, apex broadly acute, surfaces glabrous; palmately veined at base, pinnate distally. |
opposite; stipules distinct or connate at base, deeply laciniate into numerous subulate to filiform segments, 0.3–1.3 mm, glabrous; petiole 0–0.5 mm, glabrous; blade broadly ovate, broadly oblong or suborbiculate, 3–7 × 2–5.5 mm, base asymmetric, hemiamplexicaulous, margin sharply serrulate to denticulate, teeth whitish and occasionally setaelike at apex, apex obtuse, surfaces papillate, glabrous; 3-veined from base, usually only midvein conspicuous. |
Involucre | obconic, 0.9–1.1 × 0.4–0.9 mm, glabrous; glands 4, yellow-green to brown, stipitate, subcircular, 0.2 × 0.2 mm, occasionally nearly rudimentary; appendages absent on smaller glands or white to pink, shape highly variable, usually round to ± elliptic, 0.3–0.4 × 0.5–0.7 mm, distal margin entire. |
campanulate, 1.2–1.5 × 1.5–2.2 mm, papillate; glands 4, yellow to reddish, subcircular to oblong, 0.4–0.5 × 0.5–0.7 mm; appendages white to pink, 0.3–0.9 × 0.7–1.6 mm, divided into 4–6 narrowly triangular, acute segments, these occasionally 2-fid, margins entire. |
Staminate flowers | (0–)2–20. |
25–35. |
Pistillate flowers | ovary glabrous; styles 0.4 mm, 2-fid 1/2 length. |
ovary glabrous; styles 1.8–2.6 mm, unbranched, filiform. |
Capsules | depressed-globoid, 1.3–1.4 × 1.1–1.5 mm, glabrous; columella 1–1.1 mm. |
oblate, 1.5–1.7 × 1.8–2.2 mm, glabrous; columella 1.2–1.4 mm. |
Seeds | with very thin whitish mucilaginous coat over light brown testa below, ovoid-triangular, bluntly 4-angled in cross section, 0.9–1.1 × 0.5 mm, with shallow irregular depressions alternating with low, smooth ridges. |
gray to light brown, ovoid, inconspicuously 4-angled in cross section, 1.2–1.6 × 1–1.1 mm, rugose. |
Cyathia | in dense, axillary and terminal, capitate glomerules with reduced, bractlike leaves subtending cyathia; peduncle 0.5–1.8 mm. |
solitary at distal nodes; peduncle 0.5 mm, stout. |
Euphorbia hypericifolia |
Euphorbia hooveri |
|
Phenology | Flowering and fruiting early spring–late fall. | Flowering and fruiting summer–fall. |
Habitat | Open, disturbed areas, nurseries. | Drying mudflats of vernal pools in grasslands and woodlands. |
Elevation | 0–200 m. (0–700 ft.) | 20–200 m. (100–700 ft.) |
Distribution |
AL; AR; FL; GA; LA; OK; SC; TX; Central America; South America; West Indies [Introduced in Asia, Pacific Islands]
|
CA |
Discussion | Euphorbia hypericifolia is native to the New World tropics, and it is most likely adventive in the flora area (where it is most widely distributed in Florida and Texas). Reports from Arizona, California, and Maryland likely represent waifs or misidentifications. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia hooveri is federally listed as threatened; its populations are being affected severely by habitat loss and the invasion of exotic species. The species is endemic to vernal pools in six counties in the Central Valley of California. Molecular data show that E. hooveri is a hybrid species, closely related to E. albomarginata and E. serpens (Y. Yang and P. E. Berry 2011). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 272. | FNA vol. 12, p. 271. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce glomerifera, C. hypericifolia, E. glomerifera | Chamaesyce hooveri |
Name authority | Linnaeus: Sp. Pl. 1: 454. (1753) | L. C. Wheeler: Proc. Biol. Soc. Wash. 53: 9. (1940) |
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