Euphorbia prostrata |
Euphorbia strictior |
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blue weed, ground spurge, prostrate sandmat, prostrate spurge or sandmat |
panhandle spurge |
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Habit | Herbs, annual, with taproot. | Herbs, perennial, with cylindric rootstock. |
Stems | prostrate to decumbent, usually not mat-forming, 10–30 cm, crisped-villous to glabrate (proximally). |
erect, branched, densely clumped, previous year’s dead stems often persistent, 30–70 cm, glabrous. |
Leaves | opposite; stipules connate (lower side) or distinct (upper side), triangular-subulate, often lacerate distally, 0.5–1 mm, short crisped-villous to glabrate; petiole 0.5–1.5 mm, usually short crisped-villous, sometimes wooly at distal nodes; blade broadly elliptic to elliptic-oblong, ovate-spatulate, or ovate, 3–11(–15) × 3–6(–8) mm, base slightly asymmetric, rounded to slightly cordate and oblique, margins serrulate at least in distal 1/2, sometimes obscurely so, apex obtuse, abaxial surface finely crisped-villous, adaxial surface usually glabrous or glabrate, sometimes sparsely crisped-villous; 3-veined from base. |
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 | obconic, 0.6–0.9 × 0.5 mm, crisped-villous or glabrous; glands 4, reddish, oval to oblong, 0.1 × 0.1–0.2 mm; appendages white to pink, rudimentary, 0–0.2 mm, distal margin entire or irregularly scalloped. |
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 | 3–6. |
20–25. |
Pistillate flowers | ovary densely crisped-villous; styles 0.1 mm, 2-fid nearly entire length. |
ovary strigillose to tomentulose; styles 0.4–0.6 mm, 2-fid at apex. |
Capsules | broadly ovoid, 1.2–2 × 1.4–1.5 mm, crisped-villous along keels and toward base, often glabrous between keels; columella 1–1.2 mm. |
globose, all 3 locules fertile, 3.2–4.5 × 4–6.5 mm, sparsely strigillose; columella 2.5–3.9 mm. |
Seeds | white but with barely concealed brown surface beneath, ovoid, sharply 4-angled in cross section, abaxial faces plane to convex, adaxial faces concave, 0.8–1.1 × 0.5–0.7 mm, with several narrow, sharp, slightly irregular, transverse ridges. |
gray-green to gray-brown, ovoid, 3.8 × 3 mm, shallowly and obscurely pitted; caruncle absent. |
Cyathia | solitary or in small, cymose clusters at distal nodes or on congested, axillary branches; peduncle 1–2 mm. |
in terminal dichasia; peduncle (2–)4–12(–18) mm proximal and mid peduncles and cyathia abscising early, sparsely to moderately strigose to sericeous. |
2n | = 18. |
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Euphorbia prostrata |
Euphorbia strictior |
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Phenology | Flowering and fruiting early spring–fall. | Flowering and fruiting spring–fall. |
Habitat | Disturbed areas, fields, gardens, sidewalks, sandy places, ballast piles. | Open grasslands and uplands. |
Elevation | 0–1400 m. (0–4600 ft.) | 900–1400 m. (3000–4600 ft.) |
Distribution |
AL; AR; AZ; CA; CO; FL; GA; IA; IL; IN; KS; KY; LA; MA; MD; MI; MO; MS; NC; NE; NM; OH; OK; PA; SC; SD; TN; TX; UT; VA; WV; WY; Mexico; Central America; South America; West Indies [Introduced in Eurasia, Africa, Pacific Islands, Australia]
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NM; TX |
Discussion | Euphorbia prostrata is native to tropical America and possibly into the southern part of the flora area. It is likely adventive throughout most of the northern part of its range. It is widely naturalized throughout much of the rest of the tropics. (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. 285. | FNA vol. 12, p. 251. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Alectoroctonum |
Sibling taxa | ||
Synonyms | Chamaesyce prostrata | |
Name authority | Aiton: Hort. Kew. 2: 139. (1789) | Holzinger: Contr. U.S. Natl. Herb. 1: 214, plate 18. (1892) |
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