Euphorbia perennans |
Euphorbia texana |
|
---|---|---|
perennial sandmat, Terlingua spurge |
Texas spurge |
|
Habit | Herbs, perennial, with strongly thickened, woody rootstock. | Herbs, annual, with taproot. |
Stems | erect, 7–45 cm, glabrous. |
erect or ascending, unbranched or branched, sometimes extensively at crown, 7–20 cm, glabrous. |
Leaves | opposite; stipules distinct, linear-filiform in (1–)2(–3) segments, 0.3–0.4 mm, glabrous; petiole 0.8–2 mm, glabrous; blade ovate or orbiculate-deltate to reniform-deltate, 5–17 × 4–16 mm midstem leaves largest, base symmetric, cuneate, rounded to cordate, margins entire, apex acute to rounded, surfaces glabrous, often glaucous; 3-veined from base, only midvein conspicuous. |
petiole 0–0.2 mm; blade oblanceolate to oblong-oblanceolate, 8–15 × 2–5 mm, base usually attenuate, occasionally cuneate, margins crenulate distally, apex rounded to obtuse, bluntly mucronate, surfaces glabrous; venation pinnate, midvein prominent. |
Involucre | broadly-campanulate to hemispheric, 1.7–2.2 × 1.5–2.7 mm, glabrous; glands 4, green to yellow-green, elliptic to oblong, folded longitudinally, 0.3–0.5 × 0.7–1.4 mm; appendages absent. |
hemispheric, 0.5–0.9 × 0.6–1 mm, glabrous; glands (4–)5, elongate reniform, 0.1–0.3 × 0.3–0.5 mm; horns absent. |
Staminate flowers | 35–45. |
5. |
Pistillate flowers | ovary glabrous; styles 0.7–0.9 mm, 2-fid nearly entire length. |
ovary glabrous; styles 0.8–1 mm, 2-fid. |
Capsules | subglobose to broadly ovoid, 2.8–3.3 × 2.8–3.4 mm, glabrous; columella 2.2–2.7 mm. |
depressed-globose, 1.6–2 × 2.5–3 mm, 3-lobed; cocci rounded, smooth, glabrous; columella 1.2–1.5 mm. |
Seeds | white to light brown, ovoid, 3–4-angled in cross section, 2–2.4 × 1–1.2 mm, smooth to faintly transverse-wrinkled. |
brownish black, globose-lenticular, 1.4–1.5 × 1.3–1.4 mm, finely reticulate or areolate with distinct line on back; caruncle low conic, 0.4 × 0.5 mm. |
Cyathia | solitary at distal nodes or at nodes of short, axillary branches; peduncle 1.8–3 mm. |
peduncle 0.3–0.6 mm. |
Cyathial | arrangement: terminal pleiochasial branches 3, each 1–3 times 2-branched; pleiochasial bracts similar in shape and size to distal leaves; dichasial bracts distinct, elliptic to ovate, base acute to ± truncate, margins crenate distally, apex obtuse to rounded and mucronate; axillary cymose branches 1–3. |
|
Euphorbia perennans |
Euphorbia texana |
|
Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting spring. |
Habitat | Desert scrub, on cretaceous and gypseous clay, limestone hills and flats. | Open ground, prairies. |
Elevation | 900–1200 m. (3000–3900 ft.) | 0–200 m. (0–700 ft.) |
Distribution |
TX; Mexico (Chihuahua) |
LA; TX |
Discussion | Euphorbia perennans is a distinctive species with an erect habit and relatively large, firm, deltate midstem leaves. Phylogenetic data place E. perennans in a clade of primarily Chihuahuan Desert annual and perennial species (for example, E. chaetocalyx, E. fendleri, E. golondrina, E. simulans, E. spurca, and E. theriaca; Y. Yang and P. E. Berry 2011). Euphorbia perennans is known in the flora area only from Brewster County. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Euphorbia texana is related to E. alta and E. spathulata, but differs from both of those species in its smooth capsules. It is endemic to southeastern Texas and adjacent Louisiana. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 282. | FNA vol. 12, p. 311. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Chamaesyce perennans | E. dictyosperma var. leiococca, E. leiococca |
Name authority | (Shinners) Warnock & M. C. Johnston: SouthW. Naturalist 5: 170. (1960) | Boissier: Cent. Euphorb., 30. (1860) |
Web links |