Euphorbia polycarpa |
Euphorbia rosescens |
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smallseed sandmat |
rosy-pink spurge, scrub spurge |
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Habit | Herbs, perennial, with thickened rootstock. | |
Stems | erect or ascending, 15–45 cm. |
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Leaves | petiole indistinct, blade narrowly elliptic, elliptic, narrowly oblong, or obovate, 25–55 × 5–21 mm, thick and fleshy, base attenuate, apex acute or mucronulate; only midvein evident. |
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Involucre | obconic to campanulate, 2.4–3.6 × 2.5–3.6 mm, lobes ovate to oblong, 0.7–1 mm, ciliate; glands green to yellow, oblong or trapezoidal, 0.9–1.7 × 1.9–2.5 mm, distal margins crenulate-erose. |
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Staminate flowers | 25. |
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Pistillate flowers | mature gynophore not seen, styles connate 1/2 length, 3.3–3.6 mm. |
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Seeds | not seen. |
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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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Cyathial | arrangement: terminal pleiochasial branches 3, 7–16 cm, 4–7 times 2-branched; pleiochasial bracts ovate to oblong, 17–31 × 13–14 mm, margins entire, apex acute, often also mucronulate; dichasial bracts ovate or lanceolate, 6–18 × 8–12 mm, margins entire, apex acute, often also mucronate; axillary cymose branches 1–2. |
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Cyathia | peduncle 3.9–6.8 mm. |
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Mature | capsules not seen. |
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Euphorbia polycarpa |
Euphorbia rosescens |
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Phenology | Flowering and fruiting spring–summer, rarely fall. | |
Habitat | Xeric oak and pine scrub, mostly on white sands, disturbed habitats. | |
Elevation | 20–50 m. (100–200 ft.) | |
Distribution |
AZ; CA; NV; nw Mexico
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FL |
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 rosescens is a narrow-endemic, gap-specialist known only from the southern portion of the Lake Wales Ridge in Highlands County. Based on leaf characteristics, it appears to be most similar to E. telephioides. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 283. | FNA vol. 12, p. 316. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Nummulariopsis |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Chamaesyce polycarpa | |
Name authority | Bentham: Bot. Voy. Sulphur, 50. (1844) | E. L. Bridges & Orzell: Lundellia 5: 71, fig. 4. (2002) |
Web links |