Euphorbia chamaesula |
Euphorbia garberi |
|
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mountain spurge |
Garber's sandmat |
|
Habit | Herbs, perennial, with thick rootstock. | Herbs, perennial, with moderately thickened rootstock. |
Stems | erect, branched, 40–90 cm, glabrous. |
ascending, sometimes slightly woody at base, not wiry, 1–3 mm diam., 15–50 cm, canescent. |
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 or connate at base, triangular-subulate, apex divided into 2–5 subulate to subulate-filiform segments, 0.5–0.7 mm, pilose; petiole 0.5–1.1 mm, pilose; blade ovate to oblong-elliptic, 4–9(–15) × 3–6 mm, base asymmetric, obtuse to rounded, margins usually entire, rarely very sparsely serrulate, apex usually obtuse to rounded, occasionally acute to apiculate, surfaces canescent; 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, 0.6–0.9 × 0.5–0.9 mm, pilose; glands 4, brown, slightly concave, elliptic to subcircular, 0.1–0.3 × 0.2–0.4 mm; appendages white to pink, as narrow rim along gland, (0–)0.1–0.2 × 0.3–0.5 mm, surfaces pilose, distal margin entire or crenulate. |
Staminate flowers | 8–12. |
8–20. |
Pistillate flowers | ovary glabrous; styles 1–1.8 mm, 2-fid. |
ovary pilose; styles 0.6–0.7 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. |
subglobose to broadly ovoid, 1.1–1.6 × 1.3–2.1 mm, pilose; columella 1.1–1.6 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. |
gray to reddish brown, oblong-ovoid, 4-angled in cross section, 1–1.2 × 0.6–0.8 mm, flat 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 nodes of short, axillary branches; peduncle 0.2–0.4 mm. |
2n | = 26. |
|
Euphorbia chamaesula |
Euphorbia garberi |
|
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. | Beach dunes, coastal rock barrens, disturbed uplands and pine rocklands. |
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 garberi appears to be an interspecific hybrid, but its parentage is not entirely clear (Y. Yang and P. E. Berry 2011). The taxon is closely related to E. blodgettii, E. porteriana, and E. serpens. It is restricted to Collier, Miami-Dade, and Monroe counties in southern Florida and is federally listed as threatened due to impacts from habitat loss, fire suppression, and invasive species. A. Herndon (1993) synonymized E. porteriana var. keyensis under E. garberi because of its uniformly pilose 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. 268. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus chamaesula | Chamaesyce adicioides, C. brachypoda, C. garberi, C. keyensis, C. mosieri, C. porteriana var. keyensis, E. porteriana var. keyensis |
Name authority | Boissier: Cent. Euphorb., 38. (1860) | Engelmann ex Chapman: Fl. South. U.S. ed. 2, 646. (1883) |
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