Euphorbia chamaesula |
Euphorbia pergamena |
|
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mountain spurge |
rocklands spurge, Southern Florida sandmat |
|
Habit | Herbs, perennial, with thick rootstock. | Herbs, perennial, with moderately to strongly thickened rootstock. |
Stems | erect, branched, 40–90 cm, glabrous. |
prostrate to ascending, occasionally mat-forming, terete to slightly flattened, 5–18 cm, glabrous on lower surface, strigillose to sericeous on upper surface. |
Leaves | petiole 0.5–1 mm; blade elliptic to oblong, 8–20(–40) × 3–6 mm, base truncate, rounded, or attenuate, margins entire, apex obtuse or acute, sometimes slightly mucronate, surfaces glabrous; venation inconspicuous, only midvein prominent. |
opposite; stipules distinct, subulate, better developed on lower side of stem, 0.4–1.3 mm, glabrous or pilose; petiole 0.3–0.5 mm, puberulent, sericeous, or strigillose; blade oblong to ovate, 4–7 × 2–4 mm, base asymmetric, hemicordate, larger side sometimes amplexicaulous, margins entire or serrulate, apex obtuse, surfaces puberulent, sericeous, or strigillose; 3-veined from base, lateral veins inconspicuous. |
Involucre | turbinate or campanulate, 1.5–2.5 × 1.1–1.9 mm, glabrous; glands 4, crescent-shaped to semicircular, 0.5–0.8 × 1–1.8 mm; horns usually convergent, 0.2–0.8 mm. |
campanulate, 1–1.3 × 1–1.1 mm, canescent; glands 4, pinkish, oblong or reniform, 0.2 × 0.4–0.6 mm; appendages white to pink, lunate, unequal, those of proximal glands oblique, 0.6–1 × 1.4–1.6 mm, those of distal glands symmetric, 0.3 × 0.8–0.9 mm, irregularly undulate to incised. |
Staminate flowers | 8–12. |
15. |
Pistillate flowers | ovary glabrous; styles 1–1.8 mm, 2-fid. |
ovary puberulent, sericeous or strigillose; styles 0.5–1 mm, 2-fid at apex. |
Capsules | depressed-ovoid, 4.3–5 × 5–6 mm, 3-lobed; cocci rounded, smooth, glabrous; columella 3.5–4 mm. |
oblate, well exserted from involucre at maturity, 1–1.3 × 1.3–1.8 mm, puberulent, sericeous or strigillose; columella 1 mm. |
Seeds | gray to dark brown, ovoid-oblong, truncate at both ends, 2.6–3.4 × 2–2.6 mm, shallowly pitted to almost smooth; caruncle conic, 1 × 0.8 mm. |
whitish to gray, ovoid, 4-angled in cross section, 0.7–0.8 × 0.5–0.6 mm, with 3–4 transverse sulci alternating with low transverse ridges. |
Cyathial | arrangement: terminal pleiochasial branches 3–5(–6), each 3–4 times 2-branched; pleiochasial bracts ovate-lanceolate to slightly subpandurate, similar in size or wider than distal leaves; dichasial bracts distinct, lanceolate to broadly ovate, base usually truncate to rounded or subcordate, sometimes attenuate, margins entire or slightly crenulate, apex usually obtuse to acute, occasionally acuminate; axillary cymose branches 2–8. |
|
Cyathia | peduncle 1–3 mm. |
solitary at distal nodes or at nodes of short, congested, axillary shoots; peduncle to 0.5 mm. |
2n | = 26. |
|
Euphorbia chamaesula |
Euphorbia pergamena |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting year-round. |
Habitat | Clearings in ponderosa pine forests, montane roadsides, dry streambeds, creek banks, sandy and gravelly soils. | Crevices of limestone outcrops in pinelands and pine-palm woods. |
Elevation | 1700–2700 m. (5600–8900 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AZ; NM; Mexico (Chihuahua, Sonora)
|
FL; West Indies (Cuba, Hispaniola) |
Discussion | Euphorbia chamaesula is easily distinguished from other perennial members of subg. Esula in western North America by its larger capsules and the vegetative shoots (without cyathia) that arise from the distal nodes of the stem proximal to the pleiochasia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia pergamena is a Florida-listed threatened species known within the flora area from only Miami-Dade and Monroe counties in extreme southern Florida. The species is often included as a subspecies of E. adenoptera (for example, D. G. Burch 1965), but here A. Herndon (1993b) is followed and it is treated as a distinct species. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 300. | FNA vol. 12, p. 282. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus chamaesula | Chamaesyce adenoptera subsp. pergamena, C. pergamena, E. adenoptera subsp. pergamena |
Name authority | Boissier: Cent. Euphorb., 38. (1860) | Small: Bull. Torrey Bot. Club 25: 615. (1898) |
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