Atriplex dioica
Atriplex fruticulosa
rillscale, saline orache, saline saltbush, spike saltbush, thick-leaf orache, thickleaf orach, thinleaf orache
ball saltbush, ballscale, little oak orach
simple or much branched, scurfy, finally glabrate.
opposite or subopposite at least proximally;
petiole 1–3 cm;
blade strongly 3-veined from near base, lanceolate to linear-lanceolate or often triangular-ovate or lance-ovate, 30–125 × 25–60(–80) mm, thickened, basal or subbasal lobes spreading to mainly antrorse, obtuse, blade otherwise entire to sparingly dentate, typically scurfy.
numerous, proximal ones mostly short petiolate, distal ones sessile;
blade narrowly lanceolate to elliptic, 5–15(–20) × 2–4 mm, mostly acute at both ends, margin entire, densely gray scurfy.
in terminal or terminal on lateral branches, in spiciform spikes, 2–9 cm, naked except at base.
in short, dense, interrupted terminal spikes.
in small, axillary clusters.
ellipsoid, wider than long, dimorphic: brown, 1.5–3 mm wide, flattened at base, or black, 1–2 mm wide, shiny;
radicle inferior.
dark brown, 1.4–1.7 mm.
bracteoles green, blackening in age, sessile, veined or veins obscure, broadly triangular to ovate, 3–10 mm, thick, usually longer than wide, base truncate to obtuse, margin united at base, apex acute lateral angles entire or with short, sharp teeth, faces smooth or with 2 tubercles, with an inflated inner spongy layer.
bracteoles sessile or subsessile, broadly obovate to suborbicular in profile, slightly if at all compressed, 3–5 mm and almost as wide, united to middle, narrowly margined and acutely dentate beyond middle, sides tooth-crested or muricate, ± indurate.
= 36, 54.
Atriplex dioica
Atriplex fruticulosa
The distribution of the species is evidently bipartite, with an eastern coastal series extending northward mainly from New Jersey to Newfoundland and along the St. Lawrence seaway, and perhaps extending to James Bay of Hudson Bay. The western grouping lies mainly west of the 95th meridian of longitude, where it has been collected since early historical times to the present in saline marshes or other saline sites from the Yukon Territory and Northwest Territories, southward to southern California, northern Arizona, northern New Mexico, and Oklahoma.
Rafinesque gave the following information: “Stem upright angular branched, leaves petiolate, deltoid, acute, thick, scaly, the proximal opposite toothed, the distal alternate, hastated, entire: flowers dioical glomerate, male spiked naked, female unequal, sepals deltoid, warty-crested.”
The name Atriplex dioica Rafinesque antedates Chenopodium subspicatum Nuttall by half a year, being published in December 1817. Hence, it is the correct name for the widely ranging species, which has passed most recently under the name A. subspicata. Nuttall’s description of the habitat of Chenopodium subspicatum is: “In saline soils around Mandan Village, Missouri,” a designation of habitat that applies to this day.
The species forms a mirror-image set of specimens with the remarkably similar Atriplex prostrata, from which it may be distinguished in most cases by the thickened, merely ovate to lanceolate leaf blades, and less commonly but in some localities exclusively triangular-hastate to lanceolate, mostly scurfy and prominently 3-veined leaf blades. In some specimens, including the types of both Chenopodium subspicatum and Atriplex carnosa, the blades bear a hastate lobe at or above the base and sometimes match triangular-hastate profile of A. prostrata. The leaves of A. prostrata are typically thin-textured, green, not scurfy, and the veins of the blade are obscure. I. J. Bassett et al. (1983) disallowed within A. dioica (as A. subspicata) any but those with lanceolate blades, including those with the proximalmost leaves with a pair of subbasal hastate lobes. However, there are numerous specimens in which the blades are thickened and transitional in that regard to the triangular-hastate profile as in A. prostrata. Certainly those specimens with triangular or triangular-hastate leaves taken prior to the introduction of A. prostrata sometime late in the nineteenth or early twentieth century, clearly belong to the indigenous A. dioica. Whether there are intermediates between diploid (2n = 18) A. prostrata and tetraploid or hexaploid (2n = 36, 54) A. dioica is not known. There does not seem to be any consistent feature or combination of features by which all specimens can be assigned to one or the other of the two taxa. It seems probable, however, that A. prostrata is a late introduction from Europe, and that it, along with the related A. heterosperma, is now invading habitats previously occupied exclusively by the indigenous A. dioica.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
H. M. Hall and F. E. Clements (1923) indicated a close relationship between Atriplex fruticulosa and A. coulteri. Both species are described as being perennial by D. Taylor and D. H. Wilken (1993), wherein A. coulteri was inadvertently left out of the key. Perhaps the size of the fruiting bracteoles, 3–5 mm in A. fruticulosa and 2–3 mm in A. coulteri, is diagnostic. Hall and Clements pointed to differences in habit of the plant, which vary from the erect woody forms represented by the type collection (and known only from them?) to the evidently more common phase in which the leafy stems are spreading or prostrate, and herbaceous throughout except at the very base, where they are attached to a more or less woody root crown.
In some fruiting bracteoles the faces are bicristate as in the thornberi phase of Atriplex elegans, in which the teeth radiate around much of the bracteole margin, not mainly from above the middle as in the present species.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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