Euphorbia stictospora |
Euphorbia cumulicola |
|
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mat spurge, narrow-seed spurge, slimseed sandmat |
coastal dune sandmat |
|
Habit | Herbs, annual, with taproot. | Herbs, usually annual, rarely perennial, with taproot. |
Stems | prostrate, often mat-forming, occasionally with ascending tips, 5–45 cm, densely and evenly pilose to lanate. |
prostrate, 10–20 cm, glabrous. |
Leaves | opposite; stipules distinct or connate basally on one side of stem, entire or irregularly toothed or fringed, 0.5–1.2 mm, pilose to lanate; petiole 0.3–1.5 mm, pilose to lanate; blade usually oblong to oblong-obovate, occasionally nearly circular, 3–10(–15) × 2–5(–10) mm, base asymmetric, one side usually angled or rounded and other truncate-auriculate, margins minutely or conspicuously serrulate at least toward apex, apex usually broadly rounded to broadly acute, occasionally emarginate, abaxial surface often ± lighter green and without reddish spot, both surfaces sparsely to moderately pilose to lanate; 3-veined from base or venation obscure. |
opposite; stipules distinct, linear-subulate, usually divided into 3–7 linear segments, 0.5–1 mm, glabrous; petiole 0.5–1 mm, glabrous; blade narrowly elliptic to lanceolate, 4–8 × 1–2 mm uniform in size, base asymmetric, obtuse to rounded, margins entire, apex obtuse to acute, surfaces green to reddish flushed, glabrous; only midvein conspicuous. |
Involucre | obconic, 0.7–1 × 0.4–0.6 mm, moderately to densely pilose to lanate; glands 4, reddish, ± unequal, oblong, 0.1 × 0.1–0.3 mm; appendages white to strongly pinkish or reddish tinged, often unequal, sometimes 1 to all absent, 0–0.3 × 0–0.4 mm, 3-lobed or rudimentarily 1-lobed, distal margin crenate. |
campanulate, 0.9–1.1 × 1–1.3 mm, glabrous; glands 4, green to red, slightly stipitate, subcircular, 0.1 × 0.1 mm; appendages white or pink, fringing edge of gland, short-flabellate, often rudimentary, 0.1–0.2 × 0.1 mm, distal margin crenate or entire. |
Staminate flowers | 3–9. |
5–8. |
Pistillate flowers | ovary pilose to villous, hairs occasionally slightly appressed; styles 0.2–0.5 mm, unbranched or inconspicuously notched at tip. |
ovary glabrous; styles 0.2–0.3 mm, 2-fid at apex to nearly 1/2 length. |
Capsules | ovoid, 1.6–2.3 × 1.4–1.5 mm, moderately to densely villous with hairs usually slightly appressed, pubescence often concentrated on proximal 1/2 or along lobes; columella 1.5–2 mm. |
ovoid or subglobose, 1.8–2 × 2–2.3 mm, glabrous; columella 1.2–1.5 mm. |
Seeds | light to dark brown, usually mottled, sometimes with thin, white coating, often wearing away irregularly, narrowly oblong-ovoid to ellipsoid, 3–4-angled in cross section, 1–1.5 × 0.5–0.6 mm, with short, irregularly interrupted furrows, appearing partially and irregularly few-ridged. |
white to gray-brown, ovoid, terete to bluntly subangled in cross section, 1–1.3 × 1 mm, smooth or minutely pitted, with smooth brown line from top to bottom on adaxial side. |
Cyathia | solitary at leaf nodes or in small, cymose clusters on congested, axillary branches; peduncle 0.7–2.5 mm. |
solitary at distal nodes; peduncle 1 mm. |
Euphorbia stictospora |
Euphorbia cumulicola |
|
Phenology | Flowering and fruiting midsummer–early fall. | Flowering and fruiting year-round. |
Habitat | Open disturbed areas, rocky slopes. | Sandy oak hammocks, open sandy areas behind mangroves, disturbed sandy sites. |
Elevation | 100–2100 m. (300–6900 ft.) | 0–10 m. (0–0 ft.) |
Distribution |
AZ; CO; IA; KS; MO; ND; NE; NM; OK; SD; TX; WY; Mexico (Chihuahua, Durango, San Luis Potosí)
|
FL |
Discussion | Euphorbia stictospora has been recorded from New York, but this disjunct occurrence likely represents a waif or misidentification. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia cumulicola could be confused with E. bombensis, both of which are widespread in Florida, but there the latter occurs on beaches close to the ocean, whereas E. cumulicola is not a beach-inhabiting species but occurs in more protected sandy habitats such as hammocks or stabilized dunes behind mangroves. Also, E. bombensis has fleshier leaves and larger seeds, and is more compact in habit than E. cumulicola, which is a more sprawling and densely branched plant with leaves that are usually purplish tinged along the margins. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 289. | FNA vol. 12, p. 265. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Synonyms | Chamaesyce stictospora | Chamaesyce cumulicola |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 187. (1859) | (Small) Oudejans: Phytologia 67: 45. (1989) |
Web links |