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Contura Creek sandmat, Contura Creek spurge, valley spurge

Marble Canyon spurge, Ross' or Marble Canyon spurge

Habit Herbs, annual, with taproot. Herbs, perennial, with deep stout rootstock.
Stems

prostrate, 10–35 cm, glabrous or pilose.

erect, branched, densely clumped, previous year’s dead stems persistent, 25–45(–60) cm, glabrous, striate.

Leaves

opposite;

stipules distinct, subulate, 0.5–1.6 mm, glabrous or pilose;

petiole 0.3–2 mm, glabrous or pilose;

blade ovate to deltate or falcate, 2.3–13 × 1.5–6 mm, base asymmetric, usually cordate, rarely rounded, margins occasionally reddish, entire, often revolute, apex acute to obtuse, occasionally mucronate, surfaces glabrous or pilose;

midvein conspicuous, lateral veins frequently visible abaxially.

alternate, persisting, usually reflexed, occasionally spreading;

stipules 0.1–0.3 mm;

petiole 0.2–2.2 mm, glabrous;

blade narrowly ovate to lanceolate proximally, narrowly lanceolate, linear, or filiform distally, 10–32 × 0.5–6.5 mm, base cuneate, margins entire, apex acute, surfaces pilose when young, sparsely strigose or glabrous with age;

venation obscure, only midvein conspicuous.

Involucre

campanulate, 1–2.5 × 1.3–2.4 mm, glabrous or pilose;

glands 4, yellow becoming deep red, elliptic or oblong to orbiculate, 0.4–0.6 × 0.5–0.7 mm;

appendages absent or whitish, orbiculate, 0.1–0.2 × 0.3–0.5 mm, distal margin entire.

turbinate to campanulate, 2.2–3.7 × 1.5–2.5 mm, moderately strigose;

glands 5, dark green, reniform, 0.7–1.1 × 1–1.6 mm;

appendages white to pink, flabellate, 0.5–1.5 × 0.8–2.2 mm, dentate or erose.

Staminate flowers

30–70.

20–25.

Pistillate flowers

ovary glabrous or pilose;

styles 0.4–0.5 mm, 2-fid at apex.

ovary strigose;

styles 1–1.3 mm, 2-fid at apex.

Capsules

subglobose to broadly ovoid, 1.4–2.7 × 1.9–3.1 mm, glabrous or pilose;

columella 1.4–2 mm.

subglobose, 2–3 × 4 mm, sparsely strigose;

columella 2–3 mm.

Seeds

whitish gray to black, ovoid to oblong, terete to bluntly subangled in cross section, 1.1–1.7 × 0.8–1.3 mm, rugose or smooth.

gray-green to gray-brown, globose-ovoid, 1.8–2.2 × 1.2–1.6 mm, longitudinally pitted;

caruncle absent.

Cyathia

solitary at distal nodes;

peduncle 0.9–2.2 mm.

in terminal monochasia (thus appearing solitary at alternate nodes);

peduncle 0.5–2.5 (or 10–25) mm, glabrous or sparsely strigose.

Euphorbia ocellata

Euphorbia aaron-rossii

Phenology Flowering and fruiting spring–fall.
Habitat Sandy soils and dunes, occasionally rocky slopes, riparian areas.
Elevation 600–1300 m. (2000–4300 ft.)
Distribution
from FNA
AZ; CA; ID; NV; UT
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ
[BONAP county map]
Discussion

Subspecies 2 (2 in the flora).

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

Euphorbia aaron-rossii is restricted to the banks of the Colorado River in several small areas of the Grand and Marble canyons. The species is most closely related to E. strictior and E. wrightii, but due to its rarity, it has not been extensively studied.

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

Key
1. Stems, leaves, ovaries, and capsules glabrous; involucral gland appendages absent.
subsp. ocellata
1. Stems, leaves, ovaries, and capsules pilose; involucral gland appendages present.
subsp. rattanii
Source FNA vol. 12, p. 279. FNA vol. 12, p. 242.
Parent taxa Euphorbiaceae > Euphorbia > sect. Anisophyllum Euphorbiaceae > Euphorbia > sect. Alectoroctonum
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. 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. 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. vallis-mortae, E. velleriflora, E. vermiculata, E. villifera, E. virgata, E. wrightii, E. yaquiana
Subordinate taxa
E. ocellata subsp. ocellata, E. ocellata subsp. rattanii
Synonyms Chamaesyce ocellata
Name authority Durand & Hilgard: Pl. Heermann., 46. (1854) A. H. Holmgren & N. H. Holmgren: Brittonia 40: 357, figs. 1, 2. (1988)
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