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Terlingua sandmat, Terlingua spurge

desert spurge, Sonoran sandmat, tiny sandmat

Habit Herbs, annual, with slender taproot. Herbs, annual, with slender taproot.
Stems

prostrate to reclining, not mat-forming, 5–30 cm, glabrous.

prostrate, mat-forming, 5–35 cm, glabrous or shortly pilose.

Leaves

opposite;

stipules usually distinct, occasionally connate basally on lower side of stem, subulate or scalelike, usually entire, occasionally 2-fid or margin sparsely ciliate, 0.4–1 mm, glabrous;

petiole 0.7–1.2(–1.5) mm, glabrous;

blade ovate, oblong, orbiculate, or obovate, 2–7.1 × 1–3.5 mm, base slightly asymmetric, rounded, margins entire, often revolute on drying, apex usually rounded, occasionally slightly emarginate, surfaces glabrous;

venation usually obscure, only midvein conspicuous.

opposite;

stipules distinct, subulate, 0.2–0.4 mm, pilose;

petiole 0.5–1.2 mm, glabrous or pilose;

blade ovate to elliptic, 6–15 × 2–4 mm, base asymmetric, one side cuneate to rounded, other side rounded, margins entire, apex obtuse, surfaces glabrous or pilose;

venation obscure or only midvein conspicuous.

Involucre

usually turbinate-campanulate to hemispheric, occasionally suburceolate, 1–1.8 × 0.9–1.4 mm, glabrous;

glands 4, yellow-green to red-purple, sessile or short-stipitate, subcircular to slightly elliptic, 0.2–0.5 × 0.2–0.7 mm;

appendages absent or white to pink, semilunate or forming rim at edge of gland, (0–)0.1–0.4 × (0–)0.3–0.9 mm, entire or slightly crenate.

campanulate, 0.4–0.6 × 0.5–0.9 mm, glabrous or pilose;

glands 4, red, circular to oblong, 0.1 × 0.1–0.2 mm;

appendages absent.

Staminate flowers

15–36.

2–5.

Pistillate flowers

ovary glabrous;

styles 0.3–0.5 mm, 2-fid 1/2 length.

ovary usually glabrous, rarely pilose;

styles 0.1–0.2 mm, 2-fid at apex.

Capsules

broadly ovoid, 1.1–1.6 × 1.5–1.8 mm, glabrous;

columella 1.2–1.5 mm.

oblong, 1.3–1.5 × 1.1–1.3 mm, usually glabrous, rarely pilose;

columella 1–1.2 mm.

Seeds

whitish, reddish brown beneath coat, ovate, 4-angled in cross section, 0.8–1.2 × 0.5–0.8 mm, with (2–)3(–5) deep transverse ridges.

light gray, narrowly ovoid, 4-angled in cross section, 0.9–1 × 0.5–0.6 mm, smooth to slightly rugose or with 1–4 faint transverse ridges that do not pass through abaxial keel.

Cyathia

usually solitary at distal nodes, rarely clustered on short, axillary branches;

peduncle 0.3–1.3 mm.

solitary at distal nodes;

peduncle 0.4–1.4 mm.

2n

= 28.

Euphorbia theriaca

Euphorbia micromera

Phenology Flowering nearly year-round in response to sufficient rainfall.
Habitat Desert scrub, riparian woods with ash and willow, saltbush scrub, Joshua tree woodlands and grasslands, often in sandy or gravelly areas.
Elevation -20–1800 m. (-100–5900 ft.)
Distribution
from FNA
NM; TX; n Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; NM; NV; TX; UT; Mexico (Baja California, Baja California Sur, Chihuahua, Coahuila, Durango, Sonora)
[WildflowerSearch map]
[BONAP county map]
Discussion

Varieties 2 (2 in the flora).

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

Key
1. Involucral glands sessile, appendages absent.
var. theriaca
1. Involucral glands short-stipitate, appendages present, occasionally rudimentary.
var. spurca
Source FNA vol. 12, p. 290. FNA vol. 12, p. 278.
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. stictospora, E. strictior, E. telephioides, E. terracina, E. tetrapora, E. texana, 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. 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
Subordinate taxa
E. theriaca var. spurca, E. theriaca var. theriaca
Synonyms Chamaesyce theriaca Chamaesyce micromera
Name authority L. C. Wheeler: Rhodora 43: 242, plate 660, fig. A. (1941) Boissier: Proc. Amer. Acad. Arts 5: 171. (1861)
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