Euphorbia agraria |
Euphorbia yaquiana |
|
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urban spurge |
hairy Mojave spurge |
|
Habit | Herbs, perennial, with slender, spreading rootstock. | Herbs, perennial, with thick rootstock. |
Stems | erect or ascending, unbranched or branched, 30–90 cm, glabrous. |
slender, erect or ascending, sometimes sinuous, densely branched near base, 10–50 cm, moderately to densely puberulent to lanulose. |
Leaves | petiole absent; blade oblong-elliptic, 20–65 × 9–20 mm, base truncate to auriculate, margins entire, apex obtuse to rounded, surfaces glabrous; venation conspicuously pinnate, midvein prominent. |
petiole 0–1 mm; blade usually lanceolate or elliptic-lanceolate, sometimes slightly oblanceolate, 8–30 × 6–14 mm, base usually acute, occasionally short-attenuate, rarely obtuse, margins entire, apex usually acute, occasionally obtuse, acuminate, or cuspidate, surfaces sparsely to moderately puberulent to lanulose; venation pinnate, sometimes obscure, midvein prominent. |
Involucre | campanulate, 2.2–3 × 1.8–2 mm, glabrous; glands 4, crescent-shaped; 0.6–1 × 1–2 mm; horns slightly divergent to convergent, 0.1–0.2 mm. |
campanulate to broadly turbinate, 2.2–3 × 2–2.5 mm, puberulent to lanulose; glands 4, semicircular, trapezoidal, or elliptic-truncate, 0.8–1.5 × 1–2.2 mm, margins strongly crenate or dentate; horns usually absent, if present then straight, 0.1–0.2 mm, generally equaling teeth on gland margin. |
Staminate flowers | 15–20. |
12–20. |
Pistillate flowers | ovary glabrous; styles 1.2–2 mm, 2-fid. |
ovary usually puberulent, occasionally lanulose; styles 1–1.2 mm, 2-fid. |
Capsules | globose, 2–2.8 × 2.2–2.7 mm, 3-lobed; cocci rounded, smooth except finely granulate toward abaxial line, glabrous; columella 2.1–2.7 mm. |
oblong-ovoid, 3.5–4 × 3–4 mm, 3-lobed; cocci rounded, smooth, usually puberulent, occasionally lanulose; columella 2.5–3 mm. |
Seeds | gray or whitish, ovoid-oblong, 2–2.1 × 1.2–1.3 mm, smooth; caruncle ± rounded and flattened, 0.8 × 0.6 mm. |
gray to whitish, oblong cylindric, 2–3 × 1.5–1.8 mm, irregularly shallowly pitted to almost smooth; caruncle conic, 0.6 × 0.6 mm. |
Cyathial | arrangement: terminal pleiochasial branches 8–15, 1–2 times 2-branched; pleiochasial bracts similar in shape but shorter and narrower than distal leaves; dichasial bracts distinct, rhombic to reniform, base obtuse, margins entire, apex obtuse, mucronate; axillary cymose branches 12–23. |
arrangement: terminal pleiochasial branches 3–5, each 1–2 times 2-branched; pleiochasial bracts broadly ovate to subcordate, usually similar in size to, occasionally wider than, distal leaves; dichasial bracts distinct, broadly ovate to almost reniform, base obtuse, margins entire, apex obtuse, acuminate to cuspidate; axillary cymose branches 0–5. |
Cyathia | peduncle 0–2 mm. |
peduncle 0.3–0.8 mm. |
Euphorbia agraria |
Euphorbia yaquiana |
|
Phenology | Flowering and fruiting spring–summer. | Flowering and fruiting spring–summer. |
Habitat | Grasslands, roadside banks, pastures. | Ponderosa pine forests, oak-pine mixed forests, dry stream banks and beds, open scrub areas, roadsides. |
Elevation | 200–1600 m. (700–5200 ft.) | 1000–2200 m. (3300–7200 ft.) |
Distribution |
KS; MT; NE; NY; PA; WA; WY; AB; SK; Europe [Introduced in North America]
|
AZ |
Discussion | Euphorbia yaquiana is endemic to Pima and Graham counties in southern Arizona and is known only from the Santa Catalina and Pinaleño mountains. Records of E. yaquiana from southwestern Colorado (as E. incisa var. mollis) likely represent misidentifications of E. brachycera; therefore, those disjunct occurrences have been excluded here from the distribution of E. yaquiana. Euphorbia yaquiana has often been treated as a synonym of E. schizoloba var. mollis, but molecular phylogenetic data show that it is more closely related to E. brachycera and E. chamaesula (J. A. Peirson et al. 2014). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
|
Source | FNA vol. 12, p. 298. | FNA vol. 12, p. 313. |
Parent taxa | Euphorbiaceae > Euphorbia > subg. Esula | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Synonyms | Tithymalus agrarius | E. schizoloba var. mollis, E. incisa var. mollis |
Name authority | M. Bieberstein: Fl. Taur.-Caucas. 1: 375. (1808) | Tidestrom: Proc. Biol. Soc. Wash. 48: 41. (1935) |
Web links |