Euphorbia chamaesula |
Euphorbia porteriana |
|
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mountain spurge |
Porter's sandmat |
|
Habit | Herbs, perennial, with thick rootstock. | Herbs, usually annual, sometimes perennial, with slender to occasionally thickened taproot, 5 mm diam.. |
Stems | erect, branched, 40–90 cm, glabrous. |
erect to ascending, sometimes slightly woody at base, not mat-forming, 15–60 cm, usually glabrous, young branches rarely very sparsely short pubescent. |
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 usually distinct, occasionally connate basally, triangular, entire or 2–4 parted, apically ciliate, 0.3–0.4 mm, usually glabrous, rarely very sparsely short pubescent; petiole 0.5–1.5 mm, usually glabrous, rarely very sparsely short pubescent; blade ovate, oval, elliptic, oblong-elliptic, or linear-elliptic, 4–12 × 1–7 mm, base asymmetric, rounded or subcordate, margins usually entire, rarely sparsely serrate, apex obtuse to acute, sometimes mucronate, surfaces abaxially often purple or red, adaxially green, usually glabrous, rarely very sparsely short pubescent; 3-veined from base, only midvein conspicuous. |
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. |
turbinate to campanulate, 0.7–1 × 0.8–1 mm, usually glabrous, rarely very sparsely short pubescent; glands 4, brown, slightly concave, elliptic-oblong, 0.1–0.2 × 0.3–0.6 mm; appendages white or pink to dark red, usually oblong or flabellate, occasionally rudimentary and forming narrow rim at edge of gland, (0–)0.1–0.2 × 0.4–1 mm, distal margin entire or crenulate. |
Staminate flowers | 8–12. |
8–14. |
Pistillate flowers | ovary glabrous; styles 1–1.8 mm, 2-fid. |
ovary glabrous, subtended by triangular calyxlike structure; styles 0.4–0.6 mm, 2-fid 1/2 length. |
Capsules | depressed-ovoid, 4.3–5 × 5–6 mm, 3-lobed; cocci rounded, smooth, glabrous; columella 3.5–4 mm. |
broadly ovoid, 1–1.5 × 1.7–2.1 mm, glabrous; columella 1–1.4 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. |
reddish brown, ovoid, 4-angled in cross section, 0.7–1 × 0.6–0.7 mm, smooth or obscurely wrinkled. |
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; peduncle 0.5–1.1 mm. |
2n | = 26. |
|
Euphorbia chamaesula |
Euphorbia porteriana |
|
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. | Pine rocklands, coastal scrub, open hammocks. |
Elevation | 1700–2700 m. (5600–8900 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AZ; NM; Mexico (Chihuahua, Sonora)
|
FL |
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 porteriana is found in Miami-Dade County and on Big Pine Key, Monroe County. This species is closely related to E. blodgettii, E. garberi, and E. serpens. The capsules of E. porteriana are almost always completely glabrous, but the authors have seen three specimens with just a few scattered hairs on the keels. A. Herndon (1993) synonymized E. porteriana var. keyensis under E. garberi because of its uniformly hairy capsules, and that treatment is followed here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 300. | FNA vol. 12, p. 285. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus chamaesula | Chamaesyce porteriana, C. porteriana var. scoparia, C. scoparia |
Name authority | Boissier: Cent. Euphorb., 38. (1860) | (Small) Oudejans: Phytologia 67: 48. (1989) |
Web links |