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gulf sandmat

sawtooth sandmat

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

prostrate, mat-forming, 15–30 cm, strigose to strigose-tomentulose.

prostrate or ascending, 5–20 cm, usually pilose to villous, rarely glabrate.

Leaves

opposite;

stipules distinct or slightly connate at base, linear-subulate, entire or slightly parted, 0.9–1.2 mm, strigose-tomentulose;

petiole 0.5–1 mm, sparsely strigose-tomentulose;

blade broadly elliptic to narrowly oblong or ovate-lanceolate, 3–10 × 1.8–5 mm, base asymmetric, one side usually angled or rounded and the other truncate and expanded into small, rounded auricle, margins serrate (larger leaves) to serrulate (smaller leaves), apex blunt to acute, abaxial surface sparsely tomentulose to glabrate, adaxial surface glabrate; palmately veined at base, pinnate distally.

opposite;

stipules usually distinct, rarely connate at base, triangular or laciniate into subulate segments, 1–1.8 mm, glabrous;

petiole 0.3–0.8 mm, glabrous or villous;

blade oblong, ovate, or elliptic, sometimes falcate, 3–11 × 2–5 mm, base asymmetric, rounded to hemicordate, margins sharply serrate to serrulate, usually with conspicuous teeth at base of leaf, apex usually obtuse, rarely acute, surfaces frequently with red blotch in center, not papillate, sparsely pilose to glabrate;

only midvein conspicuous.

Involucre

broadly obconic, becoming distended and distorted by base of partially included capsule, 0.4–0.8 × 0.3–0.5 mm, strigose;

glands 4, red, slightly concave, ± unequal, subcircular to broadly oval, 0.1–0.2 × 0.2–0.3 mm;

appendages white to pink, usually unequal, occasionally ± equal at distal nodes, elongated toward sinus, sometimes rudimentary, 0.1–0.4 × 0.1–0.3 mm, distal margin entire or crenulate.

obconic, 0.8–1.1 × 0.8–1 mm, glabrous;

glands 4, greenish yellow, usually reniform to elliptic, rarely circular, 0.1 × 0.1–0.2 mm;

appendages usually white, rarely light pink, orbiculate, 0.1–0.3 × 0.2–0.4 mm, distal margin entire or crenulate.

Staminate flowers

3–5.

7–15.

Pistillate flowers

ovary densely strigose;

styles 0.4–0.5 mm, 2-fid 1/2 length.

ovary glabrous;

styles 0.3–0.5 mm, 2-fid 1/2 length.

Capsules

conic to truncate-ovoid, scarcely exserted from involucre, base often remaining inside involucre and splitting one side of it during maturation, 0.9–1.2 × 1–1.2 mm, sparsely to moderately strigose;

columella 0.6–1 mm.

oblate, cocci not elongated nor terminating in empty portion, 2–2.6 × 3.2–3.7 mm, glabrous;

columella 1.7–2.1 mm.

Seeds

white, tan underneath coat, ovoid to narrowly ovoid, sharply 4-angled in cross section, 0.8–0.9 × 0.4–0.6 mm, with 4 low transverse ridges often slightly extending into angles, not sulcate.

white to light brown, broadly ellipsoid to ovoid, 3–4-angled in cross section, 1.5–1.8 × 1.1–1.3(–1.5) mm, smooth to minutely rugulose or with scattered small depressions.

Cyathia

usually in small, cymose clusters on congested, axillary branches;

peduncle (0–)0.1–0.3 mm.

solitary at distal nodes;

peduncle 0.4–1.8(–2.3) mm.

Euphorbia thymifolia

Euphorbia serrula

Phenology Flowering and fruiting midsummer–early fall. Flowering and fruiting spring–fall.
Habitat Disturbed areas, often near salt water. Desert scrub, with creosote bush, grasslands with mesquite and yucca, rarely in ponderosa pine woodlands, often sandy substrates.
Elevation 0–20 m. (0–100 ft.) 300–1900 m. (1000–6200 ft.)
Distribution
from FNA
FL; LA; Mexico; South America; West Indies [Introduced in Asia, tropical Africa, Australia]
[BONAP county map]
from FNA
AZ; NM; TX; Mexico
[WildflowerSearch map]
[BONAP county map]
Discussion

Euphorbia thymifolia is a widespread tropical and subtropical weed. It is not certain where the species is native, but most likely it originated in the New World and then became widespread in the rest of the tropics. Euphorbia thymifolia is present in the flora area in southern Florida and coastal Louisiana, where it is likely adventive. Euphorbia thymifolia is generally similar to E. maculata but is characterized by its short pistillate pedicels and non-exserted capsules that remain largely enclosed by the involucre and by its unequal involucral gland appendages.

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

In Mexico, Euphorbia serrula is found from Chihuahua and Coahuila south to Puebla.

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

Source FNA vol. 12, p. 291. FNA vol. 12, p. 288.
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. theriaca, 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. 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 thymifolia Chamaesyce serrula
Name authority Linnaeus: Sp. Pl. 1: 454. (1753) Engelmann: in W. H. Emory, Rep. U.S. Mex. Bound. 2(1): 188. (1859)
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