Euphorbia cyathophora |
Euphorbia hooveri |
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fire on the mountain, painted leaf, painted poinsettia |
Hoover's sandmat, Hoover's spurge |
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Habit | Herbs, annual, with spreading taproots. | Herbs, annual, with slender to slightly thickened taproot. |
Stems | erect or ascending, 20–100 cm, glabrous, sparsely pilose, or puberulent; branches ± straight. |
prostrate, occasionally mat-forming, 4–10 cm, glabrous. |
Leaves | usually alternate, occasionally opposite proximally; petiole 2–20 mm, glabrous or pilose, or often hispid abaxially near blade junction; blade linear, lanceolate, elliptic, or wider leaves pandurate and unequally 4-lobed, occasionally polymorphic on single plants, 15–250 × 4–40 mm, base acute to cuneate, margins subulately glandular-serrulate distally, or sparsely glandular and subentire, hirtellous to glabrate, flat to revolute, apex acute to cuneate, abaxial surface sparsely pilose or glabrate, adaxial surface glabrous or sparsely puberulent; venation pinnate, midvein prominent. |
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 | campanulate, occasionally broadly so, 1.8–2.8 × 2.2–2.8 mm, glabrous; involucral lobes triangularly 3–5 lobed; gland 1, yellow-green, sessile to substipitate and narrowly to broadly attached, 1–1.4 × 0.9–1.6 mm, opening oblong (flattened without pressing), without annular rim, glabrous; appendages absent. |
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 | 7–20. |
25–35. |
Pistillate flowers | ovary glabrous; styles 1.6 mm, 2-fid nearly entire length. |
ovary glabrous; styles 1.8–2.6 mm, unbranched, filiform. |
Capsules | green, depressed-globose to ellipsoid, 2.8–3.2 × 4–4.5 mm, 3-lobed, glabrous; columella 2–2.7 mm. |
oblate, 1.5–1.7 × 1.8–2.2 mm, glabrous; columella 1.2–1.4 mm. |
Seeds | black to ashy gray or light brown, cylindric to ovoid, rounded in cross section, 2.3–3.1 × 1.9–2.5 mm, uniformly tuberculate or tubercles arranged in median, transverse ridge in cylindric seeds; caruncle absent. |
gray to light brown, ovoid, inconspicuously 4-angled in cross section, 1.2–1.6 × 1–1.1 mm, rugose. |
Cyathial | arrangement: terminal pleiochasial branches (1–)3, 1–2-branched; pleiochasial bracts 2–3(–4), often as tight, involucrate whorl, usually green with white, pink, or red at base, occasionally distal bracts wholly white, pink, or red, rarely all bracts wholly green, similar in shape and size to distal leaves; dichasial bracts often colored, similar in shape and size to distal stem leaves or highly reduced. |
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Cyathia | peduncle 1.6–2.8 mm. |
solitary at distal nodes; peduncle 0.5 mm, stout. |
2n | = 28, 56. |
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Euphorbia cyathophora |
Euphorbia hooveri |
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Phenology | Flowering and fruiting late spring–fall. | Flowering and fruiting summer–fall. |
Habitat | Bottomland forests, stream and river banks, bases of bluffs, fallow fields, roadsides, open disturbed areas. | Drying mudflats of vernal pools in grasslands and woodlands. |
Elevation | 0–1800 m. (0–5900 ft.) | 20–200 m. (100–700 ft.) |
Distribution |
AL; AR; CA; FL; GA; IA; IL; IN; KS; KY; LA; MD; MN; MO; MS; NC; NE; NM; OH; OK; SC; SD; TN; TX; UT; VA; WI; Mexico; Central America; South America; West Indies [Introduced in Eurasia, Africa, Indian Ocean Islands, Pacific Islands, Australia]
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CA |
Discussion | Euphorbia cyathophora is native to the midwestern and southeastern United States, Mexico, the West Indies, and northern South America. Leaf shape can be polymorphic on individuals of this species, but not to the extent as in E. heterophylla. (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. 319. | FNA vol. 12, p. 271. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Poinsettia cyathophora | Chamaesyce hooveri |
Name authority | Murray: Commentat. Soc. Regiae Sci. Gott. 7: 81, plate 1. (1786) | L. C. Wheeler: Proc. Biol. Soc. Wash. 53: 9. (1940) |
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