Euphorbia alta |
Euphorbia strictior |
|
---|---|---|
giant spurge, roughpod spurge, tall spurge, warty spurge |
panhandle spurge |
|
Habit | Herbs, annual or biennial, with taproot. | Herbs, perennial, with cylindric rootstock. |
Stems | erect, branched, 20–60 cm, glabrous. |
erect, branched, densely clumped, previous year’s dead stems often persistent, 30–70 cm, glabrous. |
Leaves | petiole 0–1 mm; blade oblong-spatulate, 20–50 × 7–18 mm, base broadly attenuate, margins serrulate, apex rounded to obtuse, surfaces glabrous, ± glaucous; venation pinnate, midvein prominent. |
alternate, persisting, spreading or ascending; stipules to 0.1 mm; petiole absent; blade linear to narrowly oblanceolate, (20–)40–70 × (2–)4–5 mm, base narrowly cuneate, margins entire, apex broadly acute, surfaces glabrous; venation obscure, only midvein conspicuous on wider leaves. |
Involucre | narrowly campanulate, 0.8–1.1 × 1.1–1.3 mm, glabrous; glands 4, elliptic, 0.3–0.5 × 0.5–0.7 mm; horns absent. |
campanulate or hemispheric, 1.2–2.4 × 2.2–3.2 mm, pilose; glands 5, green, broadly elliptic, 0.7–0.8 × 1.3–1.6 mm; appendages white, forming narrow rim around distal margin of gland, 0.2 × 1.5–1.8 mm, entire or erose. |
Staminate flowers | 5–10. |
20–25. |
Pistillate flowers | ovary glabrous; styles 0.5–0.9 mm, 2-fid. |
ovary strigillose to tomentulose; styles 0.4–0.6 mm, 2-fid at apex. |
Capsules | depressed-globose, 2–3 × 2.5–3.5 mm, 3-lobed; cocci rounded, papillate, papillae 0.2–0.5 mm, glabrous; columella 1.5–1.9 mm. |
globose, all 3 locules fertile, 3.2–4.5 × 4–6.5 mm, sparsely strigillose; columella 2.5–3.9 mm. |
Seeds | purple-black, ovoid, 1.6–2 × 1.3–1.7 mm, reticulate and areolate; caruncle reniform, flat, 0.5 × 0.7 mm. |
gray-green to gray-brown, ovoid, 3.8 × 3 mm, shallowly and obscurely pitted; caruncle absent. |
Cyathial | arrangement: terminal pleiochasial branches 3, 2–3 times 2-branched; pleiochasial bracts elliptic-oblanceolate to oblong, similar in size to distal leaves; dichasial bracts distinct, broadly ovate to orbiculate/reniform, base obtuse, margins serrulate, apex obtuse to rounded and often mucronulate; axillary cymose branches 6–20(–25). |
|
Cyathia | peduncle 0.5–1 mm. |
in terminal dichasia; peduncle (2–)4–12(–18) mm proximal and mid peduncles and cyathia abscising early, sparsely to moderately strigose to sericeous. |
Euphorbia alta |
Euphorbia strictior |
|
Phenology | Flowering and fruiting summer. | Flowering and fruiting spring–fall. |
Habitat | Montane pine-oak and mixed conifer forests, disturbed roadsides, logged areas. | Open grasslands and uplands. |
Elevation | 1500–3000 m. (4900–9800 ft.) | 900–1400 m. (3000–4600 ft.) |
Distribution |
AZ; NM; Mexico
|
NM; TX |
Discussion | Euphorbia alta is a montane species from southern Arizona, New Mexico, and northern and central Mexico that is very similar to and sometimes difficult to distinguish from E. spathulata. Euphorbia alta tends to be a robust biennial, whereas E. spathulata is strictly annual. The most consistent characteristic to separate these two species is that the ovaries and capsules of E. alta are distinctly papillate, with the papillae rising sharply above the surface, whereas the ovaries and capsules of E. spathulata are merely verrucose, with the protuberances lower and rounded. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia strictior is confined to a small area of the Texas Panhandle and adjacent New Mexico. The species is closely related to E. aaron-rossii and E. wrightii; it can be distinguished from E. wrightii by its larger stature, shorter and less petaloid involucral gland appendages, and early abscising proximal and mid cyathia and peduncles. Euphorbia strictior also tends to develop all three seeds in the capsule, whereas E. wrightii tends to develop only two. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 251. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Tithymalus altus | |
Name authority | Norton: N. Amer. Euphorbia, 24, plate 24. (1899) | Holzinger: Contr. U.S. Natl. Herb. 1: 214, plate 18. (1892) |
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