Euphorbia discoidalis |
Euphorbia vermiculata |
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summer spurge |
hairy sandmat, wormseed sandmat, wormseed spurge |
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Habit | Herbs, perennial, with spreading rootstock. | Herbs, annual or short-lived perennial, with slender, fibrous taproot. |
Stems | erect or ascending, unbranched, solitary or few, previous year's dead stems not persistent, 45–70 cm, usually densely puberulent to sericeous, rarely glabrous. |
prostrate to ascending or erect, not mat forming, 10–35 cm, usually sparsely to moderately strigillose, pilose, or villous, rarely glabrate hairs sometimes in longitudinal lines. |
Leaves | alternate; stipules to 0.1 mm; petiole (0–)1–2 mm (or absent), densely puberulent; blade usually linear, rarely ovate, 25–55 × 1.5–4 mm, base cuneate, margins entire, revolute, apex rounded, abaxial surface glabrous or puberulent to sericeous, adaxial surface glabrous; venation often obscure on smaller leaves, midvein conspicuous. |
opposite; stipules distinct or connate, triangular to narrowly triangular or laciniate into subulate to filiform divisions, 0.6–1.3 mm, glabrous or sparsely pilose; petiole 0.2–0.9 mm, glabrous, villous, or strigillose; blade ovate, oblong, or elliptic, often falcate, 5–18 × 3–9 mm, base asymmetric, one side rounded and other cordate, margins usually serrulate especially in distal 1/2, rarely nearly entire, apex acute or obtuse, surfaces not papillate, sparsely pilose, villous, or sericeous (especially near base), often glabrate (especially older leaves); 3–5-veined from base. |
Involucre | campanulate, 1.2–1.4 × 1.2–2 mm, sparsely to densely puberulent; glands 5, green, reniform, 0.2–0.3 × 0.5–0.6 mm; appendages white, orbiculate to oblong, (0.5–)1–1.7 × 1–1.5 mm, entire. |
obconic, 0.7–1.1 × 0.5–0.8 mm, glabrous; glands (2–3)–4, red to reddish green, circular to oblong, 0.1 × 0.1–0.2 mm; appendages absent or white, turning pink with age, flabellate, oblong, circular, or forming narrow lunate border around margin of gland, 0.1–0.3 × 0.2–0.4 mm, distal margin entire or slightly lobed. |
Staminate flowers | 20–25. |
5–15. |
Pistillate flowers | ovary glabrous or sparsely strigose; styles 0.5–1.1 mm, 2-fid at apex to 1/2 length. |
ovary glabrous; styles 0.3–0.5 mm, 2-fid 1/2 length. |
Capsules | globose, 1.8–3 × 2.5–4.8 mm, glabrous or sparsely strigose; columella 2.3–2.5 mm. |
oblate to subglobose, cocci not elongated nor terminating in empty portion, 1.4–1.8 × 1.7–2.1 mm, glabrous; columella 1.1–1.5 mm. |
Seeds | light gray, ovoid, 2 × 1.2–1.3 mm, smooth or with few, very shallow depressions; caruncle absent. |
brown, gray, or almost black, ovoid to oblong, 3–4-angled in cross section, 1.1–1.4 × 0.7–0.8 mm, rugulose and sometimes also with low transverse ridges that do not interrupt abaxial keel. |
Cyathia | in terminal pleiochasia; peduncle 5–15 mm, filiform, glabrous or very sparsely puberulent to sericeous. |
solitary at distal nodes or in small, cymose clusters at branch tips; peduncle 0.2–2.5 mm. |
Euphorbia discoidalis |
Euphorbia vermiculata |
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Phenology | Flowering and fruiting late spring–fall. | Flowering and fruiting spring–fall. |
Habitat | Sand hills, pine savannas, woodland borders, open fields with sandy soils. | Juniper-oak woodlands, temperate deciduous forests, grasslands, pine forests, oak forests with sycamores, walnuts and alders, often in disturbed areas. |
Elevation | 0–150 m. (0–500 ft.) | 0–2600 m. (0–8500 ft.) |
Distribution |
AL; FL; GA; LA; MS; TX
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AZ; CT; IL; IN; MA; MD; ME; MI; MN; NH; NJ; NM; NY; OH; PA; RI; VA; VT; WI; WV; NB; NS; ON; QC; Mexico; temperate deciduous forests; often in disturbed areas; walnuts and alders; oak forests with sycamores; pine forests; grasslands; Juniper-oak woodlands
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Discussion | M. J. Huft (1979) remarked that Euphorbia discoidalis is uncommon west of Alabama and referred many narrow-leaved specimens from Louisiana and Texas to E. corollata. K. R. Park (1998) included them in an expanded E. discoidalis, and that is followed here. The western populations can be distinguished from E. corollata by their shorter involucral gland appendages and revolute leaf margins. Further study of these western populations is warranted. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia vermiculata has an interesting disjunct distribution; it ranges from central Mexico to Arizona and New Mexico, and is also present in the northeastern United States and southeastern Canada. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 245. | FNA vol. 12, p. 292. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Alectoroctonum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Tithymalopsis discoidalis | Chamaesyce rothrockii, C. vermiculata, E. rothrockii |
Name authority | Chapman: Fl. South. U.S., 401. (1860) | Rafinesque: Amer. Monthly Mag. & Crit. Rev. 2: 206. (1818) |
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