Euphorbia polycarpa |
Euphorbia missurica |
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smallseed sandmat |
Missouri spurge, prairie sandmat, prairie spurge |
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Habit | Herbs, annual, with taproot. | |
Stems | erect or ascending, 10–60(–100) cm, glabrous, sometimes ± glaucous. |
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Leaves | opposite; stipules usually distinct, occasionally connate basally on one or both sides of stem, linear to triangular-subulate, usually deeply and irregularly fringed or lobed, rarely entire, 0.7–1.5 mm, glabrous; petiole 1–3 mm, glabrous; blade linear to narrowly oblong or narrowly lanceolate-oblong, (4–)8–30 × 3–7 mm, base symmetric or subsymmetric (usually narrower leaves), or slightly asymmetric and angled or short-tapered (wider leaves), margins entire, occasionally ± revolute, apex rounded to truncate, occasionally emarginate or mucronulate, abaxial surface pale green, adaxial surface light to bright green, both surfaces glabrous; venation obscure. |
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Involucre | broadly campanulate, 1.2–1.8 × 1.7–1.9 mm, glabrous; glands 4, yellowish green, broadly oblong to nearly circular, cupped or folded, 0.3–0.6 × 0.3–0.7 mm; appendages white or ± pinkish tinged, ovate to oblong-ovate, 0.4–2.5 × 1.1–1.7 mm, distal margin entire or slightly crenate or emarginate at tip. |
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Staminate flowers | 24–60. |
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Pistillate flowers | ovary glabrous; styles 0.5–1.4 mm, 2-fid 1/2 length. |
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Capsules | broadly ovoid-globose, 1.9–2.5 × 2–2.5(–3) mm, glabrous; columella 1.8–2.1 mm. |
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Seeds | mottled whitish to brown, ovoid to broadly ovoid-triangular, bluntly 3-angled in cross section, 1.5–2 × 1.1–1.4 mm, smooth or slightly wrinkled. |
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Euphorbia | polycarpa is a highly variable species distributed throughout the Baja California peninsula, eastern Sonora, and the arid southwestern United States from southwestern Arizona to southern Nevada and central California. |
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l | . |
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c | . |
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Wheeler | (1941) divided the species into seven varieties, the majority of which occur in Baja California Sur. |
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He | reported two of these for the United States: var. hirtella and var. polycarpa. |
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Variety | hirtella, as the name suggests, was applied to hairy plants. |
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However | , it is here treated as a synonym of var. polycarpa, because variation in pubescence shows no geographic segregation and ranges along a continuum from glabrous or sparsely to densely hairy, and because glabrous and hairy branches can occur on the same individual. |
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Cyathia | solitary or in small, cymose clusters these occasionally subtended by reduced, bractlike leaves at distal nodes or on congested, axillary branches; peduncle 1–5(–11) mm. |
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Euphorbia polycarpa |
Euphorbia missurica |
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Phenology | Flowering and fruiting late spring–late summer. | |
Habitat | Glades, ledges, bluff tops (usually calcareous), dry upland forest margins, sandy or disturbed areas. | |
Elevation | 50–1500 m. (200–4900 ft.) | |
Distribution |
AZ; CA; NV; nw Mexico
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AR; CO; IA; KS; MO; MT; ND; NE; NM; OK; SD; TX; WY
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Discussion | Varieties 5 (1 in the flora). Some of the varieties occurring in Mexico are highly divergent and appear to be sufficiently distinct to merit recognition as species. However, within the flora area, Euphorbia polycarpa is relatively uniform, and the only noteworthy variation involves the size of the involucral gland appendages. In the portion of the California Floristic Province occupied by E. polycarpa (Los Angeles, Orange, western Riverside, western San Diego, and Ventura counties) the appendages are conspicuously larger than those of plants throughout the remainder of its range in the southwestern United States (0.4–1.2 versus 0.1–0.3 mm). Large-appendaged plants are also common in Baja California and correspond well with the type collection. The taxonomic significance of this variation is not clear at this time, and the small-appendaged plants may merit segregation as an infraspecific taxon. However, no formal changes are proposed, awaiting a comprehensive review of the species throughout its range. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia missurica is similar to the western E. parryi but has a more upright growth habit and more conspicuous involucral gland appendages. Native occurrences have been documented from Minnesota (last collected in Ottertail County in 1936), but it appears to have been extirpated from that state due to habitat loss to agriculture. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 283. | FNA vol. 12, p. 278. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Chamaesyce polycarpa | Chamaesyce missurica, E. missurica var. intermedia, E. petaloidea var. intermedia |
Name authority | Bentham: Bot. Voy. Sulphur, 50. (1844) | Rafinesque: Atlantic J. 1: 146. (1832) |
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