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corrugate-seed spurge, rib-seed sandmat, ridge-seed spurge

false flowering spurge, southeastern flowering spurge

Habit Herbs, annual, with taproot. Herbs, perennial, with spreading rootstock.
Stems

prostrate, loosely mat-forming, 5–40 cm, glabrous, sometimes slightly glaucous.

erect, usually unbranched, occasionally few branched distally, solitary or few, previous year's dead stems not persistent, 30–65 cm, usually glabrous, rarely villous.

Leaves

opposite;

stipules usually distinct, linear-subulate, usually irregularly fringed or lobed, rarely laciniate, 0.4–2 mm, glabrous;

petiole 0.2–2 mm, glabrous;

blade narrowly oblong to oblong-obovate or oblong-ovate, 3–15 × 2–7 mm, base asymmetric, one side angled and other rounded to shallowly cordate, margins minutely sparsely serrulate, especially near apex and on longer side, apex rounded to obtuse, abaxial surface usually pale grayish green, adaxial surface sometimes reddish tinged or with reddish blotch, both surfaces glabrous; palmately veined at base, pinnate distally.

alternate;

stipules 1 mm;

petiole (0–)1–2(–10) mm, glabrous or densely villous;

blade lanceolate, lance-ovate, elliptic, or obovate, 40–68 × 6–18 mm, often reflexed, base cuneate to rounded, margins entire, apex usually rounded, sometimes broadly acute, abaxial surface glabrous or villous, adaxial surface usually glabrous, rarely sparsely villous;

venation occasionally obscure on small leaves, midvein conspicuous.

Involucre

obconic, 0.6–0.9 × 0.3–0.6 mm, glabrous;

glands 4, red to purple, narrowly oblong-elliptic, 0.1–0.2 × 0.1–0.5 mm;

appendages white or pinkish tinged, semilunate and fringing distal margin of gland, 0.1–0.3 × 0.1–0.3 mm, distal margin usually irregularly crenulate or lobed.

campanulate or hemispheric, 1.3–1.7 × 1.8–2.2 mm, glabrous or villous;

glands 5 (7–10 on central cyathium), green, reniform or broadly elliptic, 0.3–0.5 × 0.5–0.8 mm;

appendages white, orbiculate or narrowly flabellate, 1–2.2 × 1.5 mm, entire.

Staminate flowers

1–5.

20–25.

Pistillate flowers

ovary glabrous;

styles 0.1–0.3 mm, 2-fid 1/2 length.

ovary glabrous or sparsely villous;

styles 0.6–1.1 mm, 2-fid 1/2 length.

Capsules

broadly ovoid, 1.3–1.9 × 1.6–2 mm, glabrous;

columella 1.3–1.5 mm.

globose, 2–2.4 × 3.3–4.8 mm, glabrous or sparsely villous;

columella 1.8–2.1 mm.

Seeds

with thin white coat that readily falls off, surface below tan brown, oblong-ovoid, sharply angular in cross section, 1–1.4 × 0.6–0.9 mm, with 3–4(–6) prominent transverse ridges that usually interrupt abaxial keel.

light gray, ovoid, 2.2–2.4 × 1.6–1.8 mm, with shallow depressions;

caruncle absent.

Cyathia

solitary or in small, cymose clusters at distal nodes;

peduncle 0.5–1.6 mm.

in terminal pleiochasia;

peduncle 1–5 mm (or 15–40 mm on early flowering individuals), usually glabrous, occasionally sparsely villous.

2n

= 22.

Euphorbia glyptosperma

Euphorbia pubentissima

Phenology Flowering and fruiting early summer–fall. Flowering and fruiting spring–fall.
Habitat Stream and river banks, sand prairies, loess hill prairies, meadows, ballast, open disturbed areas, roadsides. Open fields, cliffs, woods, floodplains.
Elevation 0–1800 m. (0–5900 ft.) 0–900 m. (0–3000 ft.)
Distribution
from FNA
AZ; CA; CO; CT; IA; ID; IL; IN; KS; LA; MA; ME; MI; MN; MO; MT; ND; NE; NH; NM; NV; NY; OK; OR; SD; TN; TX; UT; VT; WA; WI; WY; AB; BC; MB; NB; NS; ON; PE; QC; SK; Mexico (Chihuahua, Coahuila, Tamaulipas, Zacatecas)
[WildflowerSearch map]
[BONAP county map]
from FNA
AL; FL; GA; LA; MD; MS; NC; SC; TN; VA; WV
[WildflowerSearch map]
[BONAP county map]
Discussion

Euphorbia glyptosperma is one of the most widespread species of the genus in North America, and it is often quite weedy. It is likely native to much of the central United States, but in areas like eastern Canada, it occurs in highly disturbed habitats, and it may be adventive there. Euphorbia glyptosperma is characterized by its prominently ridged seeds, laciniate stipules, complete lack of pubescence, and somewhat obscure toothing near the tips of the leaves.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

The taxonomic history of Euphorbia pubentissima is complex. The species has been included within a very broadly defined E. corollata in the past. Therefore, its geographic distribution appears significantly more wide-ranging in some treatments. The framework established by M. J. Huft (1979) and later by K. R. Park (1998) is followed here. Euphorbia pubentissima is recognized as a variable species restricted to the southeastern United States. The species can be distinguished from E. corollata by its shorter involucral gland appendages and smaller seeds. Euphorbia paniculata Elliott, which sometimes is applied to E. pubentissima, is an illegitimate name (a later homonym of Euphorbia paniculata Desfontaines).

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 12, p. 269. FNA vol. 12, p. 250.
Parent taxa Euphorbiaceae > Euphorbia > sect. Anisophyllum Euphorbiaceae > Euphorbia > sect. Alectoroctonum
Sibling taxa
E. aaron-rossii, E. abramsiana, E. acuta, E. agraria, E. albomarginata, E. alta, E. angusta, E. antisyphilitica, E. arizonica, E. astyla, E. austrotexana, E. bicolor, E. bifurcata, E. bilobata, E. blodgettii, E. bombensis, E. brachycera, E. capitellata, E. carunculata, E. chaetocalyx, E. chamaesula, E. cinerascens, E. commutata, E. conferta, E. cordifolia, E. corollata, E. crenulata, E. cumulicola, E. cuphosperma, E. curtisii, E. cyathophora, E. cyparissias, E. davidii, E. deltoidea, E. dendroides, E. dentata, E. discoidalis, E. eriantha, E. exigua, E. exserta, E. exstipulata, E. falcata, E. fendleri, E. florida, E. floridana, E. garberi, E. georgiana, E. geyeri, E. golondrina, E. gracillima, E. graminea, E. helioscopia, E. helleri, E. heterophylla, E. hexagona, E. hirta, E. hooveri, E. humistrata, E. hypericifolia, E. hyssopifolia, E. indivisa, E. innocua, E. inundata, E. ipecacuanhae, E. jaegeri, E. jejuna, E. laredana, E. lasiocarpa, E. lata, E. lathyris, E. longicruris, E. lurida, E. macropus, E. maculata, E. marginata, E. meganaesos, E. melanadenia, E. mendezii, E. mercurialina, E. mesembrianthemifolia, E. micromera, E. misera, E. missurica, E. myrsinites, E. nephradenia, E. nutans, E. oblongata, E. ocellata, E. ophthalmica, E. ouachitana, E. parishii, E. parryi, E. pediculifera, E. peplidion, E. peplus, E. perennans, E. pergamena, E. pinetorum, E. platyphyllos, E. platysperma, E. polycarpa, E. polygonifolia, E. polyphylla, E. porteriana, E. prostrata, E. pubentissima, E. purpurea, E. radians, E. rayturneri, E. revoluta, E. roemeriana, E. rosescens, E. schizoloba, E. serpens, E. serpillifolia, E. serrata, E. serrula, E. setiloba, E. simulans, E. spathulata, E. stictospora, E. strictior, E. telephioides, E. terracina, E. tetrapora, E. texana, E. theriaca, E. thymifolia, E. tithymaloides, E. trachysperma, E. trichotoma, E. vallis-mortae, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
E. aaron-rossii, E. abramsiana, E. acuta, E. agraria, E. albomarginata, E. alta, E. angusta, E. antisyphilitica, E. arizonica, E. astyla, E. austrotexana, E. bicolor, E. bifurcata, E. bilobata, E. blodgettii, E. bombensis, E. brachycera, E. capitellata, E. carunculata, E. chaetocalyx, E. chamaesula, E. cinerascens, E. commutata, E. conferta, E. cordifolia, E. corollata, E. crenulata, E. cumulicola, E. cuphosperma, E. curtisii, E. cyathophora, E. cyparissias, E. davidii, E. deltoidea, E. dendroides, E. dentata, E. discoidalis, E. eriantha, E. exigua, E. exserta, E. exstipulata, E. falcata, E. fendleri, E. florida, E. floridana, E. garberi, E. georgiana, E. geyeri, E. glyptosperma, E. golondrina, E. gracillima, E. graminea, E. helioscopia, E. helleri, E. heterophylla, E. hexagona, E. hirta, E. hooveri, E. humistrata, E. hypericifolia, E. hyssopifolia, E. indivisa, E. innocua, E. inundata, E. ipecacuanhae, E. jaegeri, E. jejuna, E. laredana, E. lasiocarpa, E. lata, E. lathyris, E. longicruris, E. lurida, E. macropus, E. maculata, E. marginata, E. meganaesos, E. melanadenia, E. mendezii, E. mercurialina, E. mesembrianthemifolia, E. micromera, E. misera, E. missurica, E. myrsinites, E. nephradenia, E. nutans, E. oblongata, E. ocellata, E. ophthalmica, E. ouachitana, E. parishii, E. parryi, E. pediculifera, E. peplidion, E. peplus, E. perennans, E. pergamena, E. pinetorum, E. platyphyllos, E. platysperma, E. polycarpa, E. polygonifolia, E. polyphylla, E. porteriana, E. prostrata, E. purpurea, E. radians, E. rayturneri, E. revoluta, E. roemeriana, E. rosescens, E. schizoloba, E. serpens, E. serpillifolia, E. serrata, E. serrula, E. setiloba, E. simulans, E. spathulata, E. stictospora, E. strictior, E. telephioides, E. terracina, E. tetrapora, E. texana, E. theriaca, E. thymifolia, E. tithymaloides, E. trachysperma, E. trichotoma, E. vallis-mortae, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
Synonyms Chamaesyce glyptosperma E. apocynifolia, E. corollata var. paniculata, E. corollata var. zinniiflora, E. zinniiflora, Tithymalopsis apocynifolia, T. paniculata, T. zinniiflora
Name authority Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 187. (1859) Michaux: Fl. Bor.-Amer. 2: 212. (1803)
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