Euphorbia perennans |
Euphorbia strictior |
|
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perennial sandmat, Terlingua spurge |
panhandle spurge |
|
Habit | Herbs, perennial, with strongly thickened, woody rootstock. | Herbs, perennial, with cylindric rootstock. |
Stems | erect, 7–45 cm, glabrous. |
erect, branched, densely clumped, previous year’s dead stems often persistent, 30–70 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. |
alternate, persisting, spreading or ascending; stipules to 0.1 mm; petiole absent; blade linear to narrowly oblanceolate, (20–)40–70 × (2–)4–5 mm, base narrowly cuneate, margins entire, apex broadly acute, surfaces glabrous; venation obscure, only midvein conspicuous on wider leaves. |
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. |
campanulate or hemispheric, 1.2–2.4 × 2.2–3.2 mm, pilose; glands 5, green, broadly elliptic, 0.7–0.8 × 1.3–1.6 mm; appendages white, forming narrow rim around distal margin of gland, 0.2 × 1.5–1.8 mm, entire or erose. |
Staminate flowers | 35–45. |
20–25. |
Pistillate flowers | ovary glabrous; styles 0.7–0.9 mm, 2-fid nearly entire length. |
ovary strigillose to tomentulose; styles 0.4–0.6 mm, 2-fid at apex. |
Capsules | subglobose to broadly ovoid, 2.8–3.3 × 2.8–3.4 mm, glabrous; columella 2.2–2.7 mm. |
globose, all 3 locules fertile, 3.2–4.5 × 4–6.5 mm, sparsely strigillose; columella 2.5–3.9 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. |
gray-green to gray-brown, ovoid, 3.8 × 3 mm, shallowly and obscurely pitted; caruncle absent. |
Cyathia | solitary at distal nodes or at nodes of short, axillary branches; peduncle 1.8–3 mm. |
in terminal dichasia; peduncle (2–)4–12(–18) mm proximal and mid peduncles and cyathia abscising early, sparsely to moderately strigose to sericeous. |
Euphorbia perennans |
Euphorbia strictior |
|
Phenology | Flowering and fruiting spring–fall. | Flowering and fruiting spring–fall. |
Habitat | Desert scrub, on cretaceous and gypseous clay, limestone hills and flats. | Open grasslands and uplands. |
Elevation | 900–1200 m. (3000–3900 ft.) | 900–1400 m. (3000–4600 ft.) |
Distribution |
TX; Mexico (Chihuahua) |
NM; 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 strictior is confined to a small area of the Texas Panhandle and adjacent New Mexico. The species is closely related to E. aaron-rossii and E. wrightii; it can be distinguished from E. wrightii by its larger stature, shorter and less petaloid involucral gland appendages, and early abscising proximal and mid cyathia and peduncles. Euphorbia strictior also tends to develop all three seeds in the capsule, whereas E. wrightii tends to develop only two. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 12, p. 282. | FNA vol. 12, p. 251. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Chamaesyce perennans | |
Name authority | (Shinners) Warnock & M. C. Johnston: SouthW. Naturalist 5: 170. (1960) | Holzinger: Contr. U.S. Natl. Herb. 1: 214, plate 18. (1892) |
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