Euphorbia myrsinites |
Euphorbia ouachitana |
|
---|---|---|
broad leaf glaucous spurge, donkey tail, myrtle or creeping or blue spurge, myrtle spurge |
|
|
Habit | Herbs, usually perennial, occasionally biennial, with taproot. | Herbs, annual, with taproot. |
Stems | erect or semiprostrate, unbranched or branched, 15–40 cm, succulent, glabrous. |
erect-ascending, often basally decumbent, often branched near base, 12–28 cm, glabrous. |
Leaves | petiole 0–2 mm; blade obovate, obovate-oblong, lanceolate, orbiculate, or suborbiculate, 2–30 × 3–17 mm, fleshy, base truncate or attenuate, margins entire or finely denticulate, apex acute to obtuse, cuspidate or strongly mucronate, surfaces glabrous; venation and midvein inconspicuous. |
petiole 0–3 mm; blade broadly oblanceolate to subspatulate, or proximalmost often orbiculate, 3–20 × 3–9 mm, base attenuate, margins entire, apex rounded to emarginate, surfaces glabrous; venation pinnate, midvein prominent. |
Involucre | campanulate, 2.4–2.6 × 2.3–2.5 mm, glabrous; glands 4, trapezoidal, 1–1.5 × 1.5–2.5 mm; horns divergent, thick, tips rounded, dilated, 0.5–0.9 mm. |
infundibular, 1.3–1.6 × 1–1.2 mm, glabrous; glands 4, crescent-shaped; 0.4–0.5 × 0.8–1 mm; horns divergent, 0.2–0.4 mm. |
Staminate flowers | 6–12. |
15–20. |
Pistillate flowers | ovary glabrous; styles 2.5–2.8 mm, usually unbranched. |
ovary glabrous; styles 0.8 mm, 2-fid. |
Capsules | subglobose, 5–7 × 5–6 mm, unlobed; cocci rounded to subangular, smooth, glabrous; columella 4.5–5 mm. |
ovoid-globose, 2.6–2.7 × 2.5–2.7 mm, slightly lobed; cocci rounded to ± flattened, smooth, glabrous; columella 2–2.1 mm. |
Seeds | brownish to grayish, oblong, 2.8–4.5 × 2–3.2 mm, vermiculate-rugose; caruncle substipitate, trapezoidal or mushroom-shaped, 1.3–1.5 × 0.6–0.8 mm. |
dark brown, oblong-ovoid, 1.5–2 × 1–1.6 mm, with deep, rounded pits in 3–4 regular vertical rows; caruncle reniform-ovate, conic, 0.5–0.7 × 0.5–0.8 mm. |
Cyathial | arrangement: terminal pleiochasial branches 2–12, each 1–2 times 2-branched; pleiochasial bracts similar in shape and size to distal leaves; dichasial bracts distinct, suborbiculate or reniform, base truncate, margins entire or minutely denticulate, apex obtuse, mucronulate; axillary cymose branches 0–4. |
arrangement: terminal pleiochasial branches 3, 1–3 times 2-branched; pleiochasial bracts ovate-deltate to subrhombic-ovate, shorter and wider than distal leaves; dichasial bracts connate 1/4 length, not imbricate, broadly deltate to subreniform, base truncate to broadly obtuse, margins entire, apex obtuse to bluntly acuminate; axillary cymose branches 1–5. |
Cyathia | peduncle 0.5–1 mm. |
peduncle 0.4–0.7 mm. |
2n | = 26. |
|
Euphorbia myrsinites |
Euphorbia ouachitana |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting spring. |
Habitat | Scrub oak communities, open ground near forests, shrub-steppes. | Semiopen forests, bluffs and ledges, stream banks, glades. |
Elevation | 0–2400 m. (0–7900 ft.) | 100–400 m. (300–1300 ft.) |
Distribution |
CA; CO; ID; MT; NM; OR; UT; WA; WY; BC; s Europe; w Asia [Introduced in North America]
|
AR; MO; OK; TN; TX |
Discussion | Euphorbia myrsinites is cultivated in much of the flora area, where it can tolerate cold winters. In some areas, it can locally escape from cultivation. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia ouachitana is restricted to semiopen forests and woodlands in the south-central United States. It is similar to E. commutata and has been most commonly identified as that species in the past. However, it differs in its consistently brown seeds that have pits in regular, vertical rows. The two species also differ in E. commutata’s numerous, proximal, long-petiolate elliptic leaves. The proximal leaves of E. ouachitana are spatulate with an orbiculate blade and petiolelike base. Aside from the restricted distribution of E. ouachitana in Missouri and Tennessee, the ranges of E. ouachitana and E. commutata do not overlap (see M. H. Mayfield 2013 for a detailed discussion of the distribution). Euphorbia ouachitana is most common in the Ouachita Mountains from southeastern Oklahoma to Hot Springs County, Arkansas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 305. | FNA vol. 12, p. 306. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Tithymalus myrsinites | |
Name authority | Linnaeus: Sp. Pl. 1: 461. (1753) | Mayfield: J. Bot. Res. Inst. Texas 7: 642, figs. 2[row 2, right], 6. (2013) |
Web links |
|