Euphorbia setiloba |
Euphorbia helleri |
|
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fringe spurge, shaggy spurge, Yuma sandmat |
Heller's spurge |
|
Habit | Herbs, annual, with slender taproot. | Herbs, annual, with taproot. |
Stems | prostrate, mat-forming, 5–50 cm, villous with glistening glandular hairs. |
ascending, branched proximally, 15–30 cm, glabrous. |
Leaves | opposite; stipules distinct, filiform, rudimentary to 0.2 mm, glabrous or sparsely villous with glistening glandular hairs; petiole 0.5–1.5 mm, villous; blade oblong, ovate, or elliptic, 3–7 × 2–4 mm, base asymmetric, rounded, margins entire, apex obtuse, surfaces villous; weakly 3-veined from base, commonly only midvein conspicuous. |
petiole usually 1–3 mm, absent distally; blade spatulate, 6–15 × 3–5 mm, base broadly attenuate, margins entire, apex usually obtuse to rounded, sometimes retuse, surfaces glabrous; venation pinnate, midvein prominent. |
Involucre | campanulate or urceolate, 0.7–1 × 0.5–0.8 mm, villous; glands 4, red to pink, oblong to slightly reniform, 0.1–0.2 × 0.2–0.3 mm; appendages white to pink, deeply incised into 3–6 triangular to subulate, attenuate, acute segments, 0.3–0.6 × 0.6–1 mm, segments entire. |
campanulate, 0.9–1.2 × 0.7–1 mm, glabrous; glands 4, elliptic, 0.1–0.2 × 0.3–0.4 mm; horns slightly divergent, 0.1–0.2 mm. |
Staminate flowers | 3–7. |
8–10. |
Pistillate flowers | ovary villous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.4–0.5 mm, 2-fid. |
Capsules | subglobose to ovoid, 1–1.2 mm diam., villous; columella 0.9–1.1 mm. |
depressed-globose, 2.1–2.5 × 2.5–3 mm, 3-lobed; cocci flattened, smooth, glabrous; columella 1.2–1.7 mm. |
Seeds | pink to light gray, narrowly ovoid, 4-angled in cross section, 0.8–1 × 0.5–0.6 mm, dimpled or with faint transverse ridges that do not pass through abaxial keel. |
white to light gray, ovoid, 1.4–1.6 × 1–1.2 mm, smooth; caruncle 2-lobed, thin, 0.4 × 0.7 mm. |
Cyathia | solitary at distal nodes, nodes often congested toward tips of branches; peduncle 0.2–1.6 mm. |
peduncle 0.2–0.4 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3, each 1–5 times 2-branched; pleiochasial bracts oblong, similar in size to distal leaves; dichasial bracts distinct, orbiculate-ovate to nearly reniform, subpandurate, base broadly cuneate to truncate, margins entire, apex obtuse, mucronate; axillary cymose branches 0–5. |
|
Euphorbia setiloba |
Euphorbia helleri |
|
Phenology | Flowering nearly year-round in response to sufficient moisture. | Flowering and fruiting late winter–spring. |
Habitat | Desert scrub, blackbrush scrub, Joshua tree woodlands, grasslands, often in sandy areas. | Forests, stream banks, roadsides, shaded areas with sandy, calcareous soils. |
Elevation | 20–1600 m. (100–5200 ft.) | 0–50 m. (0–200 ft.) |
Distribution |
AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Baja California Sur, Chihuahua, Durango, Sinaloa, Sonora)
|
LA; TX; Mexico (Nuevo León) |
Discussion | The smooth, white to light gray seeds of Euphorbia helleri easily distinguish it from other annual members of subg. Esula in North America. Collections of E. helleri have been made near Brownsville, Texas, and thus it is possible that the species occurs in northern Tamaulipas, Mexico. The Louisiana record (Webster Parish) likely represents introduced plants. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 288. | FNA vol. 12, p. 303. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Chamaesyce setiloba | Tithymalus helleri |
Name authority | Engelmann: in War Department [U.S.], Pacif. Railr. Rep. 5(2): 364. (1857) | Millspaugh: Bot. Gaz. 26: 268, fig. [p. 270]. (1898) |
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