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

sand-dune spurge

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

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

erect, branched, 15–40 cm, glabrous.

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.

petiole absent;

blade obovate to oblanceolate, 5–20 × 2–7 mm, base broadly attenuate, margins entire, apex acute to obtuse, surfaces glabrous;

venation pinnate, very obscure, midvein prominent.

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.

hemispheric, 1–1.5 × 1.4–2 mm, glabrous;

glands 5, elliptic to slightly crescent-shaped, 0.4–0.6 × 0.9–1.1 mm;

horns divergent, 0.1–0.2 mm.

Staminate flowers

1–5.

8–10.

Pistillate flowers

ovary glabrous;

styles 0.1–0.3 mm, 2-fid 1/2 length.

ovary glabrous;

styles 0.2–0.4 mm, 2-fid.

Capsules

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

columella 1.3–1.5 mm.

depressed-ovoid, 1.1–1.5 × 2–3 mm, strongly 3-lobed;

cocci rounded, minutely papillate, sometimes appearing smooth, glabrous;

columella 1.6–1.9 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.

white, ovoid-globose, 1.8–2 × 1.6–1.8 mm, smooth;

caruncle ± rounded and flattened, 0.3 × 0.3 mm.

Cyathia

solitary or in small, cymose clusters at distal nodes;

peduncle 0.5–1.6 mm.

peduncle 0.7–1 mm.

Cyathial

arrangement: terminal pleiochasial branches 3, each usually 1–2 times 3-branched, sometimes unbranched;

pleiochasial bracts similar in shape and size to distal leaves, alternate;

dichasial bracts distinct, obovate to oblanceolate, base broadly attenuate, margins entire, apex acute to obtuse;

axillary cymose branches 0.

2n

= 22.

Euphorbia glyptosperma

Euphorbia trichotoma

Phenology Flowering and fruiting early summer–fall. Flowering and fruiting year-round (primarily spring–summer).
Habitat Stream and river banks, sand prairies, loess hill prairies, meadows, ballast, open disturbed areas, roadsides. Coastal beaches, sand dunes, thickets.
Elevation 0–1800 m. (0–5900 ft.) 0–10 m. (0–0 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
FL; Mexico; Central America; West Indies
[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.)

Euphorbia trichotoma is found in coastal peninsular Florida from Hillsborough County south to Key West.

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

Source FNA vol. 12, p. 269. FNA vol. 12, p. 311.
Parent taxa Euphorbiaceae > Euphorbia > sect. Anisophyllum Euphorbiaceae > Euphorbia > subg. Esula
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. 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. vallis-mortae, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
Synonyms Chamaesyce glyptosperma Galarhoeus trichotomus, Tithymalus trichotomus
Name authority Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 187. (1859) Kunth: in A. von Humboldt et al., Nov. Gen. Sp. 2(fol.): 48; 2(qto.): 60. (1817)
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