Euphorbia thymifolia |
Euphorbia cyathophora |
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gulf sandmat |
fire on the mountain, painted leaf, painted poinsettia |
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Habit | Herbs, annual or perennial, with taproot. | Herbs, annual, with spreading taproots. |
Stems | prostrate, mat-forming, 15–30 cm, strigose to strigose-tomentulose. |
erect or ascending, 20–100 cm, glabrous, sparsely pilose, or puberulent; branches ± straight. |
Leaves | opposite; stipules distinct or slightly connate at base, linear-subulate, entire or slightly parted, 0.9–1.2 mm, strigose-tomentulose; petiole 0.5–1 mm, sparsely strigose-tomentulose; blade broadly elliptic to narrowly oblong or ovate-lanceolate, 3–10 × 1.8–5 mm, base asymmetric, one side usually angled or rounded and the other truncate and expanded into small, rounded auricle, margins serrate (larger leaves) to serrulate (smaller leaves), apex blunt to acute, abaxial surface sparsely tomentulose to glabrate, adaxial surface glabrate; palmately veined at base, pinnate distally. |
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. |
Involucre | broadly obconic, becoming distended and distorted by base of partially included capsule, 0.4–0.8 × 0.3–0.5 mm, strigose; glands 4, red, slightly concave, ± unequal, subcircular to broadly oval, 0.1–0.2 × 0.2–0.3 mm; appendages white to pink, usually unequal, occasionally ± equal at distal nodes, elongated toward sinus, sometimes rudimentary, 0.1–0.4 × 0.1–0.3 mm, distal margin entire or crenulate. |
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. |
Staminate flowers | 3–5. |
7–20. |
Pistillate flowers | ovary densely strigose; styles 0.4–0.5 mm, 2-fid 1/2 length. |
ovary glabrous; styles 1.6 mm, 2-fid nearly entire length. |
Capsules | conic to truncate-ovoid, scarcely exserted from involucre, base often remaining inside involucre and splitting one side of it during maturation, 0.9–1.2 × 1–1.2 mm, sparsely to moderately strigose; columella 0.6–1 mm. |
green, depressed-globose to ellipsoid, 2.8–3.2 × 4–4.5 mm, 3-lobed, glabrous; columella 2–2.7 mm. |
Seeds | white, tan underneath coat, ovoid to narrowly ovoid, sharply 4-angled in cross section, 0.8–0.9 × 0.4–0.6 mm, with 4 low transverse ridges often slightly extending into angles, not sulcate. |
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. |
Cyathia | usually in small, cymose clusters on congested, axillary branches; peduncle (0–)0.1–0.3 mm. |
peduncle 1.6–2.8 mm. |
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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2n | = 28, 56. |
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Euphorbia thymifolia |
Euphorbia cyathophora |
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Phenology | Flowering and fruiting midsummer–early fall. | Flowering and fruiting late spring–fall. |
Habitat | Disturbed areas, often near salt water. | Bottomland forests, stream and river banks, bases of bluffs, fallow fields, roadsides, open disturbed areas. |
Elevation | 0–20 m. (0–100 ft.) | 0–1800 m. (0–5900 ft.) |
Distribution |
FL; LA; Mexico; South America; West Indies [Introduced in Asia, tropical Africa, Australia] |
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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Discussion | Euphorbia thymifolia is a widespread tropical and subtropical weed. It is not certain where the species is native, but most likely it originated in the New World and then became widespread in the rest of the tropics. Euphorbia thymifolia is present in the flora area in southern Florida and coastal Louisiana, where it is likely adventive. Euphorbia thymifolia is generally similar to E. maculata but is characterized by its short pistillate pedicels and non-exserted capsules that remain largely enclosed by the involucre and by its unequal involucral gland appendages. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
Source | FNA vol. 12, p. 291. | FNA vol. 12, p. 319. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Poinsettia |
Sibling taxa | ||
Synonyms | Chamaesyce thymifolia | Poinsettia cyathophora |
Name authority | Linnaeus: Sp. Pl. 1: 454. (1753) | Murray: Commentat. Soc. Regiae Sci. Gott. 7: 81, plate 1. (1786) |
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