Euphorbia polycarpa |
Euphorbia helioscopia |
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smallseed sandmat |
euphorbe réveille-matin, mad woman's milk, summer spurge, sun spurge, wart spurge, wartweed |
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Habit | Herbs, annual, with taproot. | |
Stems | erect, unbranched or branched, 5–45 cm, usually glabrous or sparsely pilose. |
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Leaves | petiole absent or to 0.5 mm; blade obovate-spatulate, 4–40 × 2–25 mm, base cuneate, attenuate, or auriculate, margins serrulate, apex rounded, surfaces glabrous; venation pinnate, midvein prominent. |
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Involucre | cupulate, 1.5–2 × 0.7–1.1 mm, glabrous; glands 4, elliptic, 0.2–0.5 × 0.5–1 mm; horns absent. |
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Staminate flowers | 10–15. |
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Pistillate flowers | ovary glabrous; styles 0.7–1 mm, 2-fid. |
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Capsules | depressed-globose, 2.5–4 × 3.2–4.2 mm, clearly 3-lobed; cocci rounded, smooth, glabrous; columella 0.9–1.1 mm. |
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Seeds | dark brown to blackish, subovoid, 1.6–2.2 × 1.5–1.9 mm, reticulate; caruncle elliptic, 0.9–1.1 × 0.4–0.5 mm. |
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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–)5, each 1–2 times 2-branched; pleiochasial bracts obovate, wider than distal leaves; dichasial bracts distinct, obovate or rhombic, ± oblique, base rounded, truncate, or attenuate, margins serrulate, apex rounded; axillary cymose branches 0. |
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Cyathia | peduncle 0.2–1 mm. |
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Euphorbia polycarpa |
Euphorbia helioscopia |
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Phenology | Flowering and fruiting spring–fall. | |
Habitat | Roadsides, waste places. | |
Elevation | 0–1400 m. (0–4600 ft.) | |
Distribution |
AZ; CA; NV; nw Mexico
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CA; CT; DC; DE; GA; ID; IL; LA; MA; MD; ME; MI; MT; NC; NH; NJ; NY; OH; OR; PA; SC; TN; TX; VA; VT; WA; WI; WY; AB; BC; NB; NF; NS; ON; PE; QC; SK; Europe; Asia; n Africa [Introduced in North America; introduced also in South America (Argentina, Chile)]
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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 helioscopia was collected once in Minnesota in the late 1800s but apparently did not become established there. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 283. | FNA vol. 12, p. 303. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > subg. Esula |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Chamaesyce polycarpa | Galarhoeus helioscopius, Tithymalus helioscopius |
Name authority | Bentham: Bot. Voy. Sulphur, 50. (1844) | Linnaeus: Sp. Pl. 1: 459. (1753) |
Web links |
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