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hyssopleaf sandmat

Death Valley sandmat

Habit Herbs, annual, with taproot. Herbs, perennial, with thickened, woody taproot.
Stems

erect to ascending, 80 cm, sparsely to densely pilose or pilose-crinkled proximally, usually glabrous distally.

prostrate to ascending, often mat-forming, 10–45 cm, pilose to villous.

Leaves

opposite;

stipules usually connate, irregularly lacerate, 0.5–1 mm, usually glabrous, occasionally with few marginal hairs;

petiole 1–2 mm, glabrous;

blade lanceolate to oblong or falcate, 8–35 × 7–15 mm, base asymmetric, rounded, margins serrulate, apex broadly acute, abaxial surface glabrous or sparsely pilose toward base, adaxial surface glabrous; palmately veined at base, pinnate distally.

opposite;

stipules distinct or connate, subulate to filiform, 0.4–1.1 mm, densely tomentose;

petiole 0.4–1 mm, pilose to villous;

blade suborbiculate to oblong-ovate, 3–8 × 2–6 mm, base slightly asymmetric, rounded, margins entire, apex rounded to obtuse, surfaces pilose to villous; 3-veined at base, midvein conspicuous, venation often obscured by pubescence.

Involucre

obconic, 0.9–1.1 × 0.7–0.9 mm, glabrous;

glands 4(–5) (5th gland without appendage), yellow-green to maroon, elliptic to circular, 0.1–0.2 × 0.1–0.3 mm;

appendages spreading, usually white or turning reddish with age, short reniform or semilunate, 0.1–0.3 × 0.2–0.6 mm, distal margin entire or slightly undulate to crenate.

obconic-campanulate, 1.2–2.3 × 1–1.8 mm, densely pilose to villous;

glands 4, yellow to red, subcircular to oblong, 0.2–0.5 × 0.4–0.9 mm;

appendages white, flabellate to oblong, 0.1–0.7 × 0.5–1.9 mm, distal margin entire or crenulate, adaxial surface ciliate-puberulent.

Staminate flowers

4–15.

15–22(–50).

Pistillate flowers

ovary glabrous;

styles 0.5–0.9 mm, 2-fid 1/2 length.

ovary densely pilose;

styles 0.4–0.8 mm, 2-fid 1/2 length.

Capsules

depressed-ovoid, 1.5–1.6 × 1.7–1.8 mm, glabrous;

columella 1.5–2 mm.

ovoid, 1.5–2.2 × 1.8–2.2 mm, tomentose;

columella 1.2–1.6 mm.

Seeds

brown to grayish white, ovoid, slightly 4-angled in cross section, abaxial faces convex, adaxial faces slightly concave to slightly convex, 1–1.4 × 0.7–1.1 mm, with 2–3 prominent transverse ridges that do not interrupt adaxial keel, or coarsely and inconspicuously pitted-reticulate.

white, gray, or light brown, ovoid, sharply 4-angled in cross section, abaxial faces slightly convex, adaxial faces concave, 1.2–1.7 × 0.6–0.9 mm, smooth.

Cyathia

solitary or in small, cymose clusters occasionally with bractlike leaves at distal nodes or on congested, axillary branches;

peduncle 0.5–2.5 mm.

solitary at distal nodes;

peduncle 0.5–1.8 mm.

2n

= 12, 14.

Euphorbia hyssopifolia

Euphorbia vallis-mortae

Phenology Flowering and fruiting late spring–early fall. Flowering and fruiting late spring–fall.
Habitat Disturbed areas, ditches, gardens. Roadsides, desert scrub, streamsides, sandy washes.
Elevation 0–1500 m. (0–4900 ft.) 700–2000 m. (2300–6600 ft.)
Distribution
from FNA
AL; AZ; FL; GA; LA; MS; NM; SC; TX; UT; Mexico; Central America; South America; West Indies [Introduced in tropical Asia, Africa, Australia]
[WildflowerSearch map]
[BONAP county map]
from FNA
CA
[BONAP county map]
Discussion

Euphorbia hyssopifolia is native to the New World tropics and is probably also native to parts of the southern United States. However, at least some of the records from the flora area appear to be from adventive plants.

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

The specific epithet of Euphorbia vallis-mortae is a misnomer because the species does not occur in Death Valley; instead, it is found at the transition of the northern edge of the Mojave Desert and the foothills of the southern Sierra Nevada in Inyo, Kern, and San Bernardino counties.

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

Source FNA vol. 12, p. 272. FNA vol. 12, p. 291.
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. 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. trichotoma, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
Synonyms Chamaesyce hyssopifolia, E. jonesii, E. stenomeres Chamaesyce vallis-mortae
Name authority Linnaeus: Syst. Nat. ed. 10, 2: 1048. (1759) (Millspaugh) J. T. Howell: Madroño 2: 19. (1931)
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