Euphorbia chaetocalyx |
Euphorbia fendleri |
|||||
---|---|---|---|---|---|---|
bristlecup sandmat |
Fendler's sandmat |
|||||
Habit | Herbs, perennial, with woody, thickened taproot. | Herbs, perennial, with woody, thickened taproot. | ||||
Stems | usually erect, rarely slightly decumbent, often densely clustered from top of woody crown, 3–15 cm, glabrous. |
usually prostrate, decumbent, or ascending, very rarely erect, often densely clustered from top of woody crown, 5–12 cm, glabrous. |
||||
Leaves | opposite; stipules distinct, narrowly linear, usually entire, 0.5–1 mm, glabrous; petiole 0.5–1 mm, glabrous; blade ovate to lanceolate or oblong- or linear-lanceolate, 3–11 × 0.8–3(–5) mm, base slightly asymmetric, short-tapered, occasionally one side slightly rounded, margins entire, apex acute or short-acuminate, surfaces glabrous; only midvein conspicuous. |
usually opposite, rarely whorled; stipules distinct, narrowly linear, 0.5–1 mm, glabrous; petiole 0.5–1 mm, glabrous; blade usually orbiculate to ovate, rarely almost lanceolate, 3–8 × 2.5–7 mm, base slightly asymmetric, slightly cordate to rounded or obtuse, margins entire, apex rounded to obtuse, surfaces glabrous; obscurely 3–5-veined from base, only midvein conspicuous. |
||||
Involucre | campanulate to turbinate, 0.8–1.4 × 0.8–1 mm, glabrous; glands 4, yellow-brown to reddish, concave or convex, elliptic or oval, 0.2–0.4 × 0.4–0.6 mm; appendages absent or white, lanceolate-deltate to straplike, 0.2–1.1 × 0.2–0.9 mm, distal margin entire, crenate, or deeply cleft or divided. |
campanulate to turbinate or broadly cupulate, 1.1–1.7 × 1.2–1.8 mm, glabrous; glands 4, yellow-green to reddish, elliptic to oblong, 0.2–0.5 × 0.4–0.9 mm; appendages absent or white, rarely pink, often unequal, lunate to flabellate or sometimes forming crenate margin along gland, (0–)0.1–0.6 × (0–)0.5–1.5 mm, distal margin entire or toothed. |
||||
Staminate flowers | 25–35. |
25–35. |
||||
Pistillate flowers | ovary glabrous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
ovary glabrous; styles 0.3–0.4 mm, 2-fid 1/2 length. |
||||
Capsules | depressed-ovoid to depressed-globose, 1.7–2.1 × 1.6–2.4 mm, glabrous; columella 1.2–1.8 mm. |
depressed-globose, 2–2.4 × 2.2–2.5 mm, glabrous; columella 1.7–2.1 mm. |
||||
Seeds | white, ovoid-pyramidal, prominently 4-angled in cross section, 1.6–2 × 1–1.2 mm, smooth to slightly wrinkled. |
white, ovoid-pyramidal, prominently 4-angled in cross section, 1.7–2 × 1–1.2 mm, smooth to slightly wrinkled. |
||||
Cyathia | solitary at distal nodes; peduncle 0.8–1.3 mm. |
solitary at distal nodes; peduncle 0.7–1.2 mm. |
||||
2n | = 28. |
|||||
Euphorbia chaetocalyx |
Euphorbia fendleri |
|||||
Phenology | Flowering and fruiting spring–fall. | |||||
Habitat | Mountain slopes, desert scrub, pinyon-juniper woodlands, hills, canyons, grasslands, washes, roadsides, dry crevices in limestone, often in gravel and sand. | |||||
Elevation | 500–2600 m. (1600–8500 ft.) | |||||
Distribution |
AZ; NM; TX; n Mexico
|
AZ; CA; CO; KS; NE; NM; NV; OK; SD; TX; UT; WY; Mexico (Coahuila)
|
||||
Discussion | Varieties 2 (2 in the flora). Euphorbia chaetocalyx is similar to E. fendleri but can generally be distinguished from that species by its narrow, acute leaves and ± erect stems. Some authors have used the presence or absence and shape of the involucral gland appendages to help separate E. chaetocalyx from E. fendleri, but those characters appear highly variable and of little taxonomic utility. Some individuals from western Texas (Culberson and El Paso counties) and southern New Mexico appear intermediate with E. fendleri. The specific epithet of E. chaetocalyx refers to the bristly perianthlike segments that subtend the ovary, but these structures are found intermittently in both E. chaetocalyx and E. fendleri. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia fendleri is similar to E. chaetocalyx and may sometimes be confused with that species. Its prostrate to decumbent or ascending stems and small, ovate to orbiculate leaves distinguish it from E. chaetocalyx. Some authors have used the presence or absence and shape of the involucral gland appendages to help separate E. fendleri from E. chaetocalyx, but those characters appear highly variable and of little taxonomic utility; somewhat intermediate individuals occur in western Arizona, New Mexico, and Texas. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
||||
Key |
|
|||||
Source | FNA vol. 12, p. 263. | FNA vol. 12, p. 267. | ||||
Parent taxa | Euphorbiaceae > Euphorbia > sect. Anisophyllum | Euphorbiaceae > Euphorbia > sect. Anisophyllum | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | E. fendleri var. chaetocalyx, Chamaesyce chaetocalyx | Chamaesyce fendleri | ||||
Name authority | (Boissier) Tidestrom: Proc. Biol. Soc. Wash. 48: 40. (1935) | Torrey & A. Gray: in War Department [U.S.], Pacif. Railr. Rep. 2(4): 175. (1857) | ||||
Web links |