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

mat-atriplex, mat-saltbush, matscale

Habit Herbs, perennial, sometimes flowering as an annual, spreading 0.7–10 dm, slightly woody at base. Shrubs dioecious (rarely monoecious), low spreading (often appearing as if prostrate), mainly 0.3–1.5 × 3–15 dm.
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, sessile, opposite proximally, alternate distally;

blade linear to linear-oblanceolate, or oblong, 3–18 × 2–6 mm, margin entire, apex obtuse.

Staminate flowers

in glomerules in distal axils and short terminal spikes.

yellow to brownish, in clusters 3–6 mm wide, borne in spikes 1–8 cm.

Pistillate flowers

in small axillary clusters.

in leafy bracteate spikes 5–15 cm.

Seeds

brown, 1.3–1.5 mm.

brown, 1.5 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, panduriform, 3–5 × 4–6 mm, united to beyond middle, margin entire or undulate, apex rounded to acute, densely tuberculate (or smooth).

2n

= 36.

Atriplex coulteri

Atriplex corrugata

Phenology Flowering spring–fall. Flowering spring–fall.
Habitat Somewhat alkaline or clay low places, valley grasslands, coastal sage scrub, coastal slopes Saline, usually fine-textured substrates derived from Mancos Shale, Tropic Shale, Morrison, Duchesne River, and other similar formations in mat-atriplex and Castle Valley saltbush communities
Elevation 0-500 m (0-1600 ft) 1200-2200 m (3900-7200 ft)
Distribution
from FNA
CA
[WildflowerSearch map]
[BONAP county map]
from FNA
CO; NM; UT
[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.)

Mat-saltbush is known to form intermediates with both Atriplex confertifolia and A. gardneri var. cuneata. This saltbush is a valuable browse plant on the sparsely vegetated clays and silts of eastern Utah, especially on the Mancos Shale exposures, where it is often the only woody vegetation present.

(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. confertifolia, A. cordulata, A. coronata, 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 A. nuttallii var. corrugata
Name authority (Moquin-Tandon) D. Dietrich: Syn. Pl. 5: 537. (1852) S. Watson: Bot. Gaz. 16: 345. (1891)
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