Euphorbia perennans |
Euphorbia platyphyllos |
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perennial sandmat, Terlingua spurge |
broad-leaf spurge |
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Habit | Herbs, perennial, with strongly thickened, woody rootstock. | Herbs, annual, with taproot. |
Stems | erect, 7–45 cm, glabrous. |
erect, unbranched or branched, 15–80 cm, usually glabrous, rarely pilose. |
Leaves | opposite; stipules distinct, linear-filiform in (1–)2(–3) segments, 0.3–0.4 mm, glabrous; petiole 0.8–2 mm, glabrous; blade ovate or orbiculate-deltate to reniform-deltate, 5–17 × 4–16 mm midstem leaves largest, base symmetric, cuneate, rounded to cordate, margins entire, apex acute to rounded, surfaces glabrous, often glaucous; 3-veined from base, only midvein conspicuous. |
petiole absent; blade oblanceolate or obovate, 20–50 × 5–10 mm, base subcordate or cuneate, margins finely serrulate, apex usually acute, occasionally obtuse, occasionally mucronulate, surfaces usually sparsely pilose, occasionally glabrate; venation pinnate, midvein prominent. |
Involucre | broadly-campanulate to hemispheric, 1.7–2.2 × 1.5–2.7 mm, glabrous; glands 4, green to yellow-green, elliptic to oblong, folded longitudinally, 0.3–0.5 × 0.7–1.4 mm; appendages absent. |
cupulate, 0.9–1.2 × 1.3–1.6 mm, sparsely pilose; glands 4, elliptic to ovate, 0.5–0.7 × 0.7–1 mm; horns absent. |
Staminate flowers | 35–45. |
10–12. |
Pistillate flowers | ovary glabrous; styles 0.7–0.9 mm, 2-fid nearly entire length. |
ovary glabrous, styles 1.6–1.8 mm, 2-fid. |
Capsules | subglobose to broadly ovoid, 2.8–3.3 × 2.8–3.4 mm, glabrous; columella 2.2–2.7 mm. |
globose or subglobose, 2.5–3 × 2.5–3 mm, slightly 3-lobed; cocci rounded, sparsely verrucose, glabrous; columella 1.9–2.1 mm. |
Seeds | white to light brown, ovoid, 3–4-angled in cross section, 2–2.4 × 1–1.2 mm, smooth to faintly transverse-wrinkled. |
dark brown, ovoid, dorsiventrally compressed, 2–2.2 × 1.5–1.7 mm, smooth; caruncle ± reniform, 0.2–0.5 × 0.2–0.5 mm. |
Cyathia | solitary at distal nodes or at nodes of short, axillary branches; peduncle 1.8–3 mm. |
peduncle absent. |
Cyathial | arrangement: terminal pleiochasial branches (3–)5, proximalmost node 3-branched, more distal ones 1–3 times 2-branched; pleiochasial bracts similar in shape and size to distal leaves; dichasial bracts distinct, ovate-triangular, base obtuse, margins finely serrulate, apex obtuse, mucronulate; axillary cymose branches 0–7(–14). |
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Euphorbia perennans |
Euphorbia platyphyllos |
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Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting summer–fall. |
Habitat | Desert scrub, on cretaceous and gypseous clay, limestone hills and flats. | Lake shores, roadsides, waste places. |
Elevation | 900–1200 m. (3000–3900 ft.) | 0–500 m. (0–1600 ft.) |
Distribution |
TX; Mexico (Chihuahua) |
MA; MI; NC; NY; OH; PA; RI; TN; VT; WA; ON; s Europe [Introduced in North America; introduced also in South America (Argentina, Chile, Paraguay)] |
Discussion | Euphorbia perennans is a distinctive species with an erect habit and relatively large, firm, deltate midstem leaves. Phylogenetic data place E. perennans in a clade of primarily Chihuahuan Desert annual and perennial species (for example, E. chaetocalyx, E. fendleri, E. golondrina, E. simulans, E. spurca, and E. theriaca; Y. Yang and P. E. Berry 2011). Euphorbia perennans is known in the flora area only from Brewster County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Source | FNA vol. 12, p. 282. | FNA vol. 12, p. 307. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Chamaesyce perennans | Galarhoeus platyphyllos, Tithymalus platyphyllos |
Name authority | (Shinners) Warnock & M. C. Johnston: SouthW. Naturalist 5: 170. (1960) | Linnaeus: Sp. Pl. 1: 460. (1753) |
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