Flora of North America species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Euphorbia humistrata

Euphorbia revoluta

spreading sandmat

revolute spurge, threadstem sandmat, threadstem spurge
Habit Herbs, annual, with taproot. Herbs, annual, with slender taproot.
Stems

prostrate to ascending, usually mat-forming and rooting at nodes, 5–45 cm, sparsely to moderately villous to pilose (densely on young growth).

erect, 5–25 cm, glabrous.
Leaves

opposite;

stipules distinct, linear-subulate, often irregularly 2- or 3-lobed, 1–1.3 mm, sparsely villous to pilose;

petiole 0.5–1.5 mm, sparsely to moderately villous to pilose;

blade oblong-ovate to ovate-elliptic or oblong-elliptic, 4–18 × 2.5–8 mm, base strongly asymmetric, one side angled and other rounded to auriculate, margin on longer side serrulate, on shorter side subentire, apex rounded or broadly acute, abaxial surface pale grayish green, sparsely lanulose, adaxial surface usually with irregular reddish streak along midvein, usually glabrate, rarely sparsely lanulose; palmately veined at base, pinnate distally.

opposite;

stipules distinct, subulate-filiform, entire, 0.5–0.9 mm, glabrous;

petiole 0.6–1.1 mm, glabrous;

blade linear, 6–27 × 0.6–1.2 mm, base symmetric, attenuate, margins entire, revolute, apex acute, sometimes mucronate, surfaces glabrous;

only midvein conspicuous.
Involucre

obconic, 0.8–1 × 0.6–0.8 mm, sparsely villous to pilose;

glands 4, green to yellow-green (turning pink with age), usually ± unequal, narrowly oblong, 0.1–0.2 × 0.2–0.5 mm;

appendages white to reddish tinged, lunate, ± irregular and variable in shape, 0.1–0.3 × 0.2–1.5 mm, distal margin crenulate.

obconic to campanulate, 0.7–0.9 × 0.5–0.7 mm, glabrous;

glands 4, pink to dark purple, nearly circular to oblong or reniform, 0.1 × 0.1–0.2 mm;

appendages white, oblong, nearly circular, ovate, deltate, or forming thin margin around gland, rarely absent, (0–)0.1–0.2 × (0–)0.1–0.3 mm, distal margin entire.
Staminate flowers

2–5.

5–10.
Pistillate flowers

ovary short-sericeous;

styles 0.5–0.8 mm, 2-fid 1/2 length.

ovary glabrous;

styles 0.2–0.3 mm, unbranched.
Capsules

ovoid, well exserted from involucre at maturity, 1.3–1.5 × 1.2–1.6 mm, sparsely to moderately short-sericeous;

columella 0.9–1.2 mm.

ovoid to subglobose, 1.5–1.8 × 1.6–1.8 mm, glabrous;

columella 1.1–1.5 mm.
Seeds

white to light brown, oblong-ovoid, bluntly angular in cross section, 0.8–1.2 × 0.5–0.9 mm, smooth or papillate.

whitish, brick red, light gray, or light brown, narrowly to broadly ovoid, 4-angled in cross section, 0.9–1.4 × 0.7–1 mm, nearly smooth, rugulose, with faint transverse ridges, or with 2–3 well-defined transverse ridges separated by shallow depressions.
Cyathia

solitary at distal nodes;

peduncle 0.1–0.6(–2) mm.

solitary at distal nodes;

peduncles absent or to 1.5 mm.

Euphorbia humistrata

Euphorbia revoluta
Phenology Flowering and fruiting spring–late summer. Flowering and fruiting summer–late fall.
Habitat Stream and river banks, gravel bars, floodplains, pond edges, disturbed fields, railroads, roadsides. Desert scrub, sagebrush scrub, juniper woodlands, Joshua tree-pinyon pine woodlands, oak woodlands, grasslands, chaparral, pine-oak forests.
Elevation 0–300 m. (0–1000 ft.) 600–2500 m. (2000–8200 ft.)
Distribution
from FNA
AL; AR; FL; GA; IL; IN; KS; KY; LA; MO; MS; OH; OK; TN; TX; VA; WV
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; NM; NV; TX; UT; Mexico (Baja California, Chihuahua, Coahuila, Sonora, Zacatecas)
[WildflowerSearch map]
[BONAP county map]
Discussion

Euphorbia humistrata is distributed throughout the Mississippi River valley and along other major river systems in the central and eastern United States. There are scattered reports of this species as a waif or as introduced farther north and/or east (for example, Minnesota, New York, North Carolina, Ontario, South Dakota, and Wisconsin), but the authors have not been able to verify these occurrences. Euphorbia humistrata is similar to E. maculata and is often confused with that species in herbaria. It can be distinguished from E. maculata by its tendency to root at the stem nodes, its longer styles, and its seeds that lack low transverse ridges and that are more bluntly angled. When growing side-by-side, E. humistrata has an overall less congested appearance and its cyathia are not as numerous or crowded as those of E. maculata.

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

Euphorbia revoluta is a distinctive, easily recognizable species by virtue of the combination of unbranched styles and linear leaves with symmetric bases. The species ranges through northern Mexico into the southwestern United States and is composed of three well-marked, geographically distinct races that can be distinguished by their seeds. The first of these races occurs primarily in pine-oak forest of the Sierra Madre Occidental of Mexico (Chihuahua and Sonora) and barely enters the flora area in the Huachuca Mountains of southeastern Arizona; the seeds are brick red and nearly smooth. The second race is widespread in the Chihuahuan Desert from northern Mexico to southeastern New Mexico and southwestern Texas; its seeds are whitish to light gray and possess two or three well-defined transverse ridges separated by shallow depressions. The third race corresponds to the type collection and is characterized by grayish white to light brown seeds that are rugulose or with faint transverse ridges; it occurs in northwestern Mexico (Baja California and Sonora) and throughout the arid southwestern United States. It is probable that further study will justify the taxonomic segregation of these races as either distinct species or subspecies.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 12, p. 272. FNA vol. 12, p. 286.
Parent taxa Euphorbiaceae > Euphorbia > sect. Anisophyllum Euphorbiaceae > Euphorbia > sect. Anisophyllum
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. glyptosperma, E. golondrina, E. gracillima, E. graminea, E. helioscopia, E. helleri, E. heterophylla, E. hexagona, E. hirta, E. hooveri, 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. 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 humistrata Chamaesyce revoluta
Name authority Engelmann: in A. Gray, Manual ed. 2, 386. (1856) Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. (1859)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in Flora of North America yet, or it's listed under a synonym. And please note that Flora of North America is still missing several plant families, including Fabaceae, Apiaceae, Boraginaceae, and Polemoniaceae.)

Choose a data source: Flora of North America

The species comparison tool is brought to you by:
Northwest Wildflowers