Euphorbia crenulata |
Euphorbia angusta |
|
---|---|---|
Chinese caps, western wood spurge |
Blackfoot sandmat, narrow-leaf spurge |
|
Habit | Herbs, usually biennial, occasionally annual, with taproot. | Herbs, perennial, with moderately to strongly thickened rootstock. |
Stems | erect, sometimes decumbent at base, unbranched or branched, 12–40 cm, glabrous. |
erect, 12–43 cm, uniformly strigose. |
Leaves | petiole 0–2 mm; blade obovate-spatulate to oblanceolate, 8–22 × 3–10 mm, base broadly attenuate, margins entire or slightly crisped, apex obtuse to ± rounded, minutely apiculate, surfaces glabrous; venation pinnate, midvein prominent. |
opposite; stipules distinct, linear-subulate or nodiform to papilliform nodiform to papilliform stipules often reddish brown, 0.1–0.7 mm, strigose; petiole 0.3–1.2 mm, strigose; blade: proximal ovate to ovate-elliptic, distal linear to elliptic-linear, 7–41 × 2–5 mm, distal leaf blades more than 6 times as long as wide, base asymmetric, cuneate to rounded, margins entire, often involute on drying, apex acute, surfaces usually short strigose, occasionally glabrous adaxially; venation pinnate, only midvein conspicuous. |
Involucre | campanulate, 1.8–2.1 × 1.6–1.8 mm, glabrous; glands 4, crescent-shaped, 0.6–1.2 × 1.5–2.3 mm; horns slightly divergent to slightly convergent, 0.4–0.6 mm. |
turbinate to campanulate-turbinate, 1–1.5 × 1–1.4 mm, strigose; glands 4, green to yellow-green, concave, narrowly oblong, 0.2–0.4 × 0.4–0.7 mm; appendages white, flabellate, 0.5–1.1 × 0.3–0.5 mm, distal margin shallowly and irregularly toothed. |
Staminate flowers | 11–18. |
16–26. |
Pistillate flowers | ovary glabrous; styles 0.9–1.4 mm, 2-fid. |
ovary strigose; styles 0.3–0.5 mm, 2-fid at apex to almost 1/2 length. |
Capsules | subovoid, 2.5–3 × 3.5–4 mm, 3-lobed; cocci rounded, smooth or puncticulate, glabrous; columella 1.9–2.3 mm. |
broadly ovoid, 2–2.6 × 2.5–3 mm, strigose; columella 1.6–2.2 mm. |
Seeds | cream and brown mottled, oblong-ovoid to nearly globose, 2–2.5 × 1.4–1.7 mm, usually irregularly vermiculate-ridged and large-pitted, occasionally tuberculate or nearly smooth; caruncle reniform, conic, 0.5–0.6 × 0.5–0.7 mm. |
white, ovoid, 4-angled in cross section, 1.7–2.2 × 1.1–1.2 mm, transversely low-ridged or wrinkled. |
Cyathial | arrangement: terminal pleiochasial branches 3, each 2-branched; pleiochasial bracts obovate to orbiculate-reniform, wider than distal leaves; dichasial bracts usually connate 1/3–1/2 length (often only on one side), rarely only connate basally, triangular ovate to reniform, base truncate to perfoliate, margins erose-denticulate to subentire, apex rounded to obtuse, rarely apiculate; axillary cymose branches 0–5. |
|
Cyathia | peduncle 0–0.5 mm. |
solitary at distal nodes; peduncle 1.1–2.4 mm. |
2n | = 28. |
|
Euphorbia crenulata |
Euphorbia angusta |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting early spring–fall. |
Habitat | Conifer, oak, and mixed forests, coastal scrub, grasslands, barrens and outcrops, roadsides. | Rocky limestone soils. |
Elevation | 30–1800 m. (100–5900 ft.) | 400–1200 m. (1300–3900 ft.) |
Distribution |
CA; CO; NM; OR
|
TX; Mexico (Coahuila) |
Discussion | Euphorbia crenulata is most common in the central valleys of California and southern Oregon; it occurs disjunctly in southwestern Colorado and northwestern New Mexico. Previous reports from Arizona are based on misidentified specimens. Euphorbia crenulata is closely related to E. commutata. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia angusta, which in the flora area is known from the trans-Pecos region to the Edwards Plateau, is easily recognized by its erect habit, linear leaves, and relatively showy involucral gland appendages with toothed margins. The species is closely related to E. acuta and the Mexican endemic E. johnstonii Mayfield (M. H. Mayfield 1991); it is not only morphologically distinctive but is also the only species in sect. Anisophyllum with C3 photosynthesis (R. F. Sage et al. 2011; T. L. Sage et al. 2011; G. L. Webster 1975). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 301. | FNA vol. 12, p. 260. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus crenulatus | Chamaesyce angusta |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 192. (1859) | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) |
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