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Coulter's orach, Coulter's orache, Coulter's saltbush

shadscale, shadscale saltbush, sheepfat, spiny saltbush

Habit Herbs, perennial, sometimes flowering as an annual, spreading 0.7–10 dm, slightly woody at base. Shrubs, dioecious, 3–8 dm, spinescent.
Stems

frequently tinged with red, much branched, sparsely scurfy.

Leaves

many, sessile or short petiolate;

blade obovate, oblong, oblanceolate, or elliptic, (5–)7–20 × 1–3(–5) mm, base cuneate, margin entire, apex acute.

persistent, alternate;

petiole 1–4 mm;

blade orbiculate to ovate, elliptic, or oval, 9–25(–45) × 4–20(–25) mm, margin entire, apex obtuse.

Staminate flowers

in glomerules in distal axils and short terminal spikes.

yellow, in clusters 2–4 mm wide or in spikes to 1 cm, axillary, in foliose-bracteate, divaricately branched panicles 3–15 cm.

Pistillate flowers

in small axillary clusters.

in similar paniculate inflorescences.

Seeds

brown, 1.3–1.5 mm.

1.5–2 mm wide.

Fruiting

bracteoles sessile or subsessile, broadly obovate, 2–3 mm and as broad or about as broad, united 1/2 of length, margin free, deeply and sharply dentate, narrowed at summit, faces smooth or sometimes tuberculate.

bracteoles sessile or subsessile, suborbiculate to rhombic or elliptic, 4–12 mm and wide, body indurate, terminal teeth distinct, foliaceous, shorter than bracteoles, entire or toothed below, terminal teeth spreading at maturity, faces smooth, lacking appendages.

2n

= 18, 36, 54+.

Atriplex coulteri

Atriplex confertifolia

Phenology Flowering spring–fall. Flowering spring–fall.
Habitat Somewhat alkaline or clay low places, valley grasslands, coastal sage scrub, coastal slopes Gravelly to fine-textured soils in greasewood, mat-atriplex, other salt desert shrub, sagebrush, pinyon-juniper, and ponderosa pine communities
Elevation 0-500 m (0-1600 ft) 600-2200 m (2000-7200 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CA; CO; ID; MT; ND; NM; NV; OR; TX; UT; WY
[WildflowerSearch map]
[BONAP county map]
Discussion

Of conservation concern.

Atriplex coulteri is closely allied to the geographically disjunct A. fruticulosa, from which it is said to differ in the compressed, small (2.5–3 mm) versus thickened and larger (3–5 mm) bracts. Specimens of A. fruticulosa, including the type, examined by me have bracteoles compressed-thickened, but hardly “globoid” as stated in the key to the species by H. M. Hall and F. E. Clements (1923). Additional specimens borrowed from California might clarify the situation; otherwise the two species are sufficiently close as to be treated as a single entity.

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

Shadscale forms hybrids with Atriplex canescens, A. garrettii, A. corrugata, and A. gardneri varieties. It is, however, closely allied to A. parryi and A. spinifera. The plants are widely dispersed, typically on saline substrates but less commonly on essentially non-saline ones, through large areas of the western United States and adjacent Canada and Mexico, on both raw and exposed geological strata and on alluvium.

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

Source FNA vol. 4, p. 363. FNA vol. 4.
Parent taxa Chenopodiaceae > Atriplex > subg. Obione > sect. Obione > subsect. Arenariae Chenopodiaceae > Atriplex > subg. Pterochiton
Sibling taxa
A. acanthocarpa, A. amnicola, A. argentea, A. californica, A. canescens, A. confertifolia, A. cordulata, A. coronata, A. corrugata, A. covillei, A. dioica, A. elegans, A. fruticulosa, A. gardneri, A. garrettii, A. glabriuscula, A. gmelinii, A. graciliflora, A. heterosperma, A. holocarpa, A. hortensis, A. hymenelytra, A. joaquiniana, A. klebergorum, A. laciniata, A. lentiformis, A. leucophylla, A. lindleyi, A. linearis, A. littoralis, A. matamorensis, A. mucronata, A. nudicaulis, A. nummularia, A. oblongifolia, A. obovata, A. pacifica, A. parishii, A. parryi, A. patula, A. pentandra, A. phyllostegia, A. pleiantha, A. polycarpa, A. powellii, A. prostrata, A. pusilla, A. rosea, A. saccaria, A. semibaccata, A. serenana, A. spinifera, A. suberecta, A. suckleyi, A. tatarica, A. torreyi, A. truncata, A. tularensis, A. watsonii, A. wolfii, A. wrightii
A. acanthocarpa, A. amnicola, A. argentea, A. californica, A. canescens, A. cordulata, A. coronata, A. corrugata, A. coulteri, A. covillei, A. dioica, A. elegans, A. fruticulosa, A. gardneri, A. garrettii, A. glabriuscula, A. gmelinii, A. graciliflora, A. heterosperma, A. holocarpa, A. hortensis, A. hymenelytra, A. joaquiniana, A. klebergorum, A. laciniata, A. lentiformis, A. leucophylla, A. lindleyi, A. linearis, A. littoralis, A. matamorensis, A. mucronata, A. nudicaulis, A. nummularia, A. oblongifolia, A. obovata, A. pacifica, A. parishii, A. parryi, A. patula, A. pentandra, A. phyllostegia, A. pleiantha, A. polycarpa, A. powellii, A. prostrata, A. pusilla, A. rosea, A. saccaria, A. semibaccata, A. serenana, A. spinifera, A. suberecta, A. suckleyi, A. tatarica, A. torreyi, A. truncata, A. tularensis, A. watsonii, A. wolfii, A. wrightii
Synonyms Obione coulteri Obione confertifolia, A. collina, A. subconferta, Obione rigida
Name authority (Moquin-Tandon) D. Dietrich: Syn. Pl. 5: 537. (1852) (Torrey & Frémont) S. Watson: Proc. Amer. Acad. Arts 9: 119. (1874)
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