Euphorbia exstipulata |
Euphorbia blodgettii |
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square-seed spurge, squareseed or Clark Mountain spurge |
limestone sandmat |
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Habit | Herbs, annual, with slender taproot. | Herbs, usually annual, occasionally perennial, with slender to slightly thickened taproot, 3.5 mm diam.. |
Stems | erect, 5–26 cm, uniformly puberulent to hispidulous or glabrous; branches arcuate. |
prostrate to decumbent, loosely mat-forming, often rooting at nodes, 10–45 cm, glabrous. |
Leaves | opposite; petiole 1–3 mm, often indistinct, glabrous or puberulent; blade linear to narrowly elliptic or ovate, 14–42 × 3–28 mm, base attenuate, margins coarsely serrate, occasionally revolute, apex acute to obtuse, abaxial surface sparsely hispidulous to strigillose, adaxial surface glabrous; midvein conspicuous. |
opposite; stipules distinct, subulate filiform segments (lower side), or connate forming conspicuous, broad deltate scale (upper side), toothed, 0.5–1 mm, glabrous; petiole 0.7–1 mm, glabrous; blade ovate to oblong-elliptic, 4–10 × 2–5 mm, base asymmetric, subcordate to rounded, margins usually entire, occasionally toothed, apex usually obtuse to rounded, occasionally acute to apiculate, surfaces without red blotch, glabrous; 3-veined from base, only midvein conspicuous. |
Involucre | turbinate to campanulate, 1.1–1.5 × 1–1.3 mm, glabrous, pilose or puberulent; involucral lobes divided into several linear lobes; glands 4(–5), yellow to pink, sessile and broadly attached, 0.2 × 0.3–0.4 mm, opening oblong to nearly circular, glabrous; appendages usually petaloid, white to pink, ovate to trapezoidal, occasionally absent, not incurved and covering glands, 0.2–0.4 × 0.3–0.8 mm, entire, undulate, or conspicuously divided into triangular segments, glabrous. |
turbinate to campanulate, 0.5–0.6 × 0.4–0.6 mm, glabrous; glands 4, red, slightly concave, elliptic-oblong, 0.1 × 0.1–0.3 mm; appendages white to pink, unequal, pair near sinus lunate to oblong, 0.1–0.2 × 0.1–0.3 mm, distal margin entire, crenulate, or irregularly sinuate, other pair sometimes rudimentary, 0–0.1 × 0.1–0.3 mm, distal margin crenulate or entire. |
Staminate flowers | 10–12. |
8–12. |
Pistillate flowers | ovary puberulent on keels, styles 0.8–1.1 mm, 2-fid 1/2 to nearly entire length. |
ovary glabrous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
Capsules | broadly depressed-oblong to ovoid, 2.7–3.3 × 3.1–3.9 mm, puberulent (with appressed hairs usually concentrated on keels); columella 1.9–2.5 mm. |
broadly ovoid, 1.2–1.7 × 1.4–1.9 mm, glabrous; columella 1.2–1.6 mm. |
Seeds | white to gray or light brown, ovoid, bluntly 4-angled in cross section, 1.9–2.5 × 1.4–1.7 mm, tuberculate, often with 2 transverse ridges; caruncle 0.1 × 0.2 mm. |
gray to reddish brown, oblong-ovoid, 4-angled in cross section, 0.9–1.1 × 0.5–0.6 mm, flat or obscurely wrinkled. |
Cyathial | arrangement: terminal cymose or dichasial branches usually 1–2, occasionally reduced to monochasia, 1–2-branched; pleiochasial bracts 2–4, often whorled, wholly green or paler green at base, similar in shape and size to distal leaves or slightly narrower; dichasial bracts similar in shape to distal leaves but smaller or highly reduced. |
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Cyathia | peduncle 1–1.9 mm. |
solitary or in small, cymose clusters at distal nodes of stem or on congested, axillary branches; peduncle 0.4–0.6 mm. |
Euphorbia exstipulata |
Euphorbia blodgettii |
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Phenology | Flowering and fruiting summer–fall. | Flowering and fruiting year-round. |
Habitat | Desert scrub, grasslands, mesquite savannas, oak and oak-juniper woodlands. | Coastal sand dunes and disturbed upland sandy areas. |
Elevation | 800–2000 m. (2600–6600 ft.) | 0–20 m. (0–100 ft.) |
Distribution |
AZ; CA; NM; TX; UT; WY; Mexico (Chihuahua, Coahuila, Durango, Guanajuato, San Luis Potosí, Sonora, Zacatecas)
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FL |
Discussion | Euphorbia exstipulata is native from Texas to California and northern Mexico. The species was found once in the late nineteenth century in Wyoming but has not been re-collected there. Broad-leaved plants have been segregated as var. lata, but the variation in leaf shape is continuous and no varieties are formally recognized here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia blodgettii is found only in peninsular Florida. It is closely related to E. garberi, E. porteriana, and E. serpens (Y. Yang and P. E. Berry 2011). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 322. | FNA vol. 12, p. 261. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Poinsettia | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | E. exstipulata var. lata | Chamaesyce blodgettii, C. nashii |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 189. (1859) | Engelmann ex Hitchcock: Rep. (Annual) Missouri Bot. Gard. 4: 126, plate 13. (1893) |
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