Euphorbia pediculifera |
Euphorbia bombensis |
|
---|---|---|
Carrizo Mountain sandmat |
Dixie sandmat, southern seaside spurge |
|
Habit | Herbs, usually annual, rarely perennial, with taproot. | |
Stems | prostrate or slightly ascending, 10–40 cm, glabrous. |
|
Leaves | opposite; stipules distinct, linear-subulate, usually divided into 3 linear segments, 1–2 mm, glabrous; petiole 1–2 mm, glabrous; blade oblong or elliptic-oblong, 4–15 × 2–3 mm, base asymmetric to nearly symmetric, obtuse, margins entire, apex acute to mucronate, surfaces green to reddish flushed, glabrous; only midvein conspicuous. |
|
Involucre | obconic-campanulate, 1.2–1.6 × 1.5–1.7 mm, glabrous; glands 4, green to red, slightly concave, elliptic, oblong, or subcircular, 0.3–0.5 × 0.4–0.6 mm; appendages white or pink, semilunate, fringing edge of gland, sometimes rudimentary, (0–)0.1–0.5(–0.7) × 0.5–0.8 mm, distal margin crenate to entire. |
|
Staminate flowers | 5–16. |
|
Pistillate flowers | ovary glabrous; styles 0.2–0.3 mm, 2-fid 1/2 length. |
|
Capsules | broadly ovoid, 2–2.1 × 2.3–2.5 mm, glabrous; columella 1.5–2 mm. |
|
Seeds | ashy white, plumply ovoid, terete to bluntly subangled in cross section, 1.5–1.9 × 1–1.2 mm, smooth or minutely pitted, with smooth brown line from top to bottom on adaxial side. |
|
Euphorbia | pediculifera can be variable in terms of leaf shape and the extent of pubescence, but the species is readily identified by the short, appressed hairs on the leaves and the distinctive seed that is encircled by a series of round, transverse ridges. |
|
Cyathia | solitary or in small, cymose clusters at distal nodes; peduncle 0.5–3 mm. |
|
Euphorbia pediculifera |
Euphorbia bombensis |
|
Phenology | Flowering and fruiting spring–fall. | |
Habitat | Coastal dunes and sandy habitats. | |
Elevation | 0–30 m. (0–100 ft.) | |
Distribution |
AZ; CA; nw Mexico
|
AL; FL; GA; LA; MS; NC; SC; TX; VA; Mexico; Central America; n South America (Venezuela)
|
Discussion | Varieties 2 (1 in the flora). Euphorbia pediculifera var. linearifolia S. Watson is found only near Guaymas in southwestern Sonora, Mexico. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia bombensis is similar and closely related to E. cumulicola, E. geyeri, and E. polygonifolia. It differs notably from E. polygonifolia in its smaller, plumply ovoid seeds. L. C. Wheeler (1941) suggested that where E. bombensis and E. polygonifolia are sympatric, E. bombensis grows farther away from the shore. Euphorbia bombensis is usually distinguished from E. cumulicola by the latter's smaller, isomorphic leaves that lack any fleshiness, smaller seeds, and diffuse growth habit. Euphorbia bombensis differs from E. geyeri in its usually shorter, less conspicuous involucral gland appendages and its geographic restriction to the coastal plain. However, Wheeler pointed out that plants of E. bombensis from Texas have more or less conspicuous involucral gland appendages. Examination of specimens confirmed that E. bombensis occasionally has conspicuous involucral gland appendages, and because of this, E. bombensis and E. geyeri are difficult to distinguish in Texas. This clade of closely related, sand and dune specialists requires further study. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 281. | FNA vol. 12, p. 261. |
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum |
Sibling taxa | ||
Subordinate taxa | ||
Synonyms | Chamaesyce pediculifera | Chamaesyce ammannioides, C. bombensis, C. ingallsii, E. ammannioides |
Name authority | Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. (1859) | Jacquin: Enum. Syst. Pl., 22. (1760) |
Web links |