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mat spurge, narrow-seed spurge, slimseed sandmat

ashy sandmat

Habit Herbs, annual, with taproot. Herbs, perennial, with moderately to strongly thickened rootstock.
Stems

prostrate, often mat-forming, occasionally with ascending tips, 5–45 cm, densely and evenly pilose to lanate.

prostrate to decumbent, mat-forming, 5–30 cm, appressed wooly, strigillose, or short-sericeous.

Leaves

opposite;

stipules distinct or connate basally on one side of stem, entire or irregularly toothed or fringed, 0.5–1.2 mm, pilose to lanate;

petiole 0.3–1.5 mm, pilose to lanate;

blade usually oblong to oblong-obovate, occasionally nearly circular, 3–10(–15) × 2–5(–10) mm, base asymmetric, one side usually angled or rounded and other truncate-auriculate, margins minutely or conspicuously serrulate at least toward apex, apex usually broadly rounded to broadly acute, occasionally emarginate, abaxial surface often ± lighter green and without reddish spot, both surfaces sparsely to moderately pilose to lanate; 3-veined from base or venation obscure.

opposite;

stipules distinct, subulate, 0.2–0.5 mm, appressed wooly to sericeous;

petiole 0.3–0.8 mm, appressed wooly to sericeous;

blade ovate to elliptic, 1.5–5.5 × 1.3–4 mm, base asymmetric, obtuse to hemicordate, margins entire often reddish, apex usually obtuse, occasionally acute (young leaves), surfaces sericeous to strigillose or slightly pilose, adaxial surface often glabrous; 3-veined from base but only midvein conspicuous.

Involucre

obconic, 0.7–1 × 0.4–0.6 mm, moderately to densely pilose to lanate;

glands 4, reddish, ± unequal, oblong, 0.1 × 0.1–0.3 mm;

appendages white to strongly pinkish or reddish tinged, often unequal, sometimes 1 to all absent, 0–0.3 × 0–0.4 mm, 3-lobed or rudimentarily 1-lobed, distal margin crenate.

turbinate, 0.8–1.3 × 1.2–2 mm, appressed wooly, sericeous, or strigillose;

glands 4, purple-black, elliptic to oblong, 0.2–0.3 × 0.4–0.6 mm;

appendages absent or reddish pink, forming narrow rim around distal margin of gland, 0–0.1 × 0–0.6 mm, distal margin entire, crenulate, or erose.

Staminate flowers

3–9.

15–20.

Pistillate flowers

ovary pilose to villous, hairs occasionally slightly appressed;

styles 0.2–0.5 mm, unbranched or inconspicuously notched at tip.

ovary canescent;

styles 0.3–0.5 mm, 2-fid at apex.

Capsules

ovoid, 1.6–2.3 × 1.4–1.5 mm, moderately to densely villous with hairs usually slightly appressed, pubescence often concentrated on proximal 1/2 or along lobes;

columella 1.5–2 mm.

subglobose to broadly ovoid, 1.3–1.7 × 1.5–1.8 mm, canescent;

columella 1–1.3 mm.

Seeds

light to dark brown, usually mottled, sometimes with thin, white coating, often wearing away irregularly, narrowly oblong-ovoid to ellipsoid, 3–4-angled in cross section, 1–1.5 × 0.5–0.6 mm, with short, irregularly interrupted furrows, appearing partially and irregularly few-ridged.

white to pinkish or light brown, ovoid, 4-angled in cross section, 1–1.4 × 0.6–0.8 mm, smooth to rugulose or rarely with 1–2 inconspicuous transverse ridges.

Cyathia

solitary at leaf nodes or in small, cymose clusters on congested, axillary branches;

peduncle 0.7–2.5 mm.

solitary at distal nodes;

peduncle 0.2–0.3 mm.

2n

= 32.

Euphorbia stictospora

Euphorbia cinerascens

Phenology Flowering and fruiting midsummer–early fall. Flowering and fruiting year-round (mostly spring–fall).
Habitat Open disturbed areas, rocky slopes. Desert scrub, oak and juniper woodlands, thorn scrub, shrublands, grasslands, frequently on limestone substrates.
Elevation 100–2100 m. (300–6900 ft.) 70–1400 m. (200–4600 ft.)
Distribution
from FNA
AZ; CO; IA; KS; MO; ND; NE; NM; OK; SD; TX; WY; Mexico (Chihuahua, Durango, San Luis Potosí)
[WildflowerSearch map]
[BONAP county map]
from FNA
TX; Mexico
[BONAP county map]
Discussion

Euphorbia stictospora has been recorded from New York, but this disjunct occurrence likely represents a waif or misidentification.

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

In the flora area, Euphorbia cinerascens is found only in southern and western Texas. In Mexico, it is found from Chihuahua east to Tamaulipas, south to Guanajuato.

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

Source FNA vol. 12, p. 289. FNA vol. 12, p. 264.
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. 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. 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. 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. trichotoma, E. vallis-mortae, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
Synonyms Chamaesyce stictospora Chamaesyce cinerascens
Name authority Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 187. (1859) Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 186. (1859)
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