Euphorbia alta |
Euphorbia melanadenia |
|
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giant spurge, roughpod spurge, tall spurge, warty spurge |
red-gland spurge, squaw sandmat |
|
Habit | Herbs, annual or biennial, with taproot. | Herbs, perennial, with moderately to strongly thickened rootstock. |
Stems | erect, branched, 20–60 cm, glabrous. |
ascending to erect, 5–20 cm, sericeous to appressed-villous. |
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. |
opposite; stipules distinct (lower side) and connate (upper side), linear, 0.5–1 mm, densely pilose; petiole 0.8–1.5 mm, tomentose; blade ovate, 1.2–5 × 0.8–2.9 mm, base asymmetric, hemicordate, margins entire, apex rounded to acute, surfaces tomentose; venation inconspicuous. |
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, 0.6–1.1 × 0.7–1 mm, tomentose; glands 4, deep red to purple, elliptic, 0.3–0.4 × 0.4–0.7 mm; appendages white or becoming pink with age, oblong to flabellate, 0.4–0.7(–1) × 0.7–1.2 mm, distal margin entire or erose. |
Staminate flowers | 5–10. |
45–80. |
Pistillate flowers | ovary glabrous; styles 0.5–0.9 mm, 2-fid. |
ovary tomentose, styles 0.5–0.8 mm, 2-fid nearly entire length. |
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. |
ovoid, 1.4–1.8 × 1.4–1.7 mm, tomentose; columella 1.2–1.5 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 to tan, oblong, 4-angled in cross section, 1–1.2 × 0.4–0.6 mm, smooth to wrinkled or alveolate. |
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. |
solitary at distal nodes; peduncle (0.6–)1.4–1.9 mm. |
Euphorbia alta |
Euphorbia melanadenia |
|
Phenology | Flowering and fruiting summer. | Flowering and fruiting year-round. |
Habitat | Montane pine-oak and mixed conifer forests, disturbed roadsides, logged areas. | Rocky slopes, river washes, dry to wet soils. |
Elevation | 1500–3000 m. (4900–9800 ft.) | 400–1400 m. (1300–4600 ft.) |
Distribution |
AZ; NM; Mexico
|
AZ; CA; Mexico (Baja California, Sonora)
|
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 melanadenia is similar in appearance to E. cinerascens, but E. melanadenia has conspicuous involucral gland appendages whereas E. cinerascens has inconspicuous appendages or lacks them entirely. Euphorbia melanadenia occurs in Arizona and southern California, whereas E. cinerascens is found only in southern and western Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 276. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalus altus | Chamaesyce melanadenia |
Name authority | Norton: N. Amer. Euphorbia, 24, plate 24. (1899) | Torrey: in War Department [U.S.], Pacif. Railr. Rep. 4(5): 135. (1857) |
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