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

four-corners orach

Habit Herbs, perennial, sometimes flowering as an annual, spreading 0.7–10 dm, slightly woody at base. Herbs, branching from base, mainly 0.5–1.5 dm, glabrous or sparingly scurfy.
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.

alternate to subopposite, petiolate;

blade ovate to suborbiculate, 5–18(–20) mm, about as wide, margin entire, apex obtuse to acute.

Staminate flowers

in glomerules in distal axils and short terminal spikes.

in short terminal spikes.

Pistillate flowers

in small axillary clusters.

Seeds

brown, 1.3–1.5 mm.

falling at maturity, black, 1.5 mm, shining, smooth.

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 short stipitate, compressed, 3–7 mm wide and about as long, entire;

perianth consisting of 5 hyaline, sparsely ciliate scales 1–1.2 mm.

Atriplex coulteri

Atriplex pleiantha

Phenology Flowering spring–fall. Flowering late summer–fall.
Habitat Somewhat alkaline or clay low places, valley grasslands, coastal sage scrub, coastal slopes Salt-desert shrub community
Elevation 0-500 m (0-1600 ft) 1400-1500 m (4600-4900 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
AZ; CO; NM; UT
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.)

Source FNA vol. 4, p. 363. FNA vol. 4, p. 345.
Parent taxa Chenopodiaceae > Atriplex > subg. Obione > sect. Obione > subsect. Arenariae Chenopodiaceae > Atriplex > subg. Obione > sect. Pleianthae
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. confertifolia, 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. 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 Proatriplex pleiantha
Name authority (Moquin-Tandon) D. Dietrich: Syn. Pl. 5: 537. (1852) W. A. Weber: Madroño 10: 189, figs. 1, 2. (1950)
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