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Published In: Species Plantarum 2: 1052. 1753. (1 May 1753) (Sp. Pl.) Name publication detailView in BotanicusView in Biodiversity Heritage Library
 

Project Name Data (Last Modified On 8/26/2009)
Acceptance : Accepted
Project Data     (Last Modified On 7/9/2009)
Status: Introduced

 

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1. Atriplex L. (saltbush, orach, orache)

Plants annual, monoecious (dioecious perennial herbs or shrubs elsewhere), the roots not tuberous-thickened. Stems prostrate to erect, sometimes weak and supported by surrounding plants, not succulent, not appearing jointed, usually much-branched, glabrous or sparsely to moderately mealy, at least when young. Leaves alternate or opposite toward the stem base, well developed, not or only slightly succulent, mostly petiolate. Leaf blades narrowly lanceolate to ovate or triangular, often with a pair of pronounced, spreading basal lobes, flattened in cross-section, not clasping the stem, rounded or narrowed to a sharply pointed tip, the margins entire or sometimes slightly wavy, the surfaces glabrous or sparsely to densely mealy. Inflorescences axillary and/or terminal, consisting of small flower clusters (sometimes solitary flowers), these often appearing as interrupted spikes, or small panicles of interrupted spikes, the staminate flowers intermingled with the pistillate flowers or positioned more terminally along the inflorescence, the flowers not sunken into the axis. Bracts of staminate flowers absent (or sometimes minute bracts subtending flower clusters); bracts of pistillate flowers 2, longer than the flower (absent in some flowers of dimorphic species), more or less fused basally, enclosing the fruit, broadly triangular to rhombic or nearly circular, sometimes strongly veined or ornamented with flaplike or hornlike projections, the margins entire or toothed. Calyx absent in pistillate flowers (present sometimes in dimorphic species, then similar to that of staminate flowers), calyx in staminate flowers 1.5–2.5 mm long, deeply (3–)5-lobed, the lobes spaced evenly around the flower, the tips erect or incurved. Staminate flowers with (3–)5 stamens. Pistillate flowers with the ovary superior. Styles 2, short, sometimes fused at the very base, the stigmas 1 per style, linear. Fruits broadly obovate to nearly circular in outline, somewhat flattened laterally, usually indehiscent, the wall thin and papery to membranous. Seed adhering loosely to the fruit wall, usually positioned vertically, sometimes dimorphic, somewhat flattened, the surface smooth, brown or black, shiny, the coiled embryo usually apparent. About 300 species, nearly worldwide.

Some shrubby species of Atriplex (saltbushes) are major components of scrubby vegetation types in the arid portions of the western United States. Nearly all of the species are adapted to grow well in saline soils. The eastern species are annuals of disturbed habitats and for the most part are closely related components of a circumboreal polyploid complex. Species determinations among the taxa present in Missouri are difficult, and mature fruits are usually necessary for certain identification.

 

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1 1. Pistillate flowers with the bracts fused to well above the base, at maturity the fused portion becoming hardened and somewhat bony, the fruit difficult to separate from the bracts

2 2. Leaf blades with the margins all irregularly wavy or more commonly with irregular blunt teeth ... 6. A. ROSEA

Atriplex rosea
3 2. Some or all of the leaves with the margins entire, sometimes most of the leaves with a single pair of spreading basal lobes

4 3. Lowermost leaves opposite or subopposite; leaf blades linear to oblanceolate or elliptic, mostly more than 4 times as long as wide and widest at or above the midpoint, appearing green on the upper surface, silvery gray on the undersurface ... 8. A. WRIGHTII

Atriplex wrightii
5 3. Leaves all alternate, the blades ovate to ovate-triangular, less than 3 times as long as wide and widest toward the base, appearing silvery gray on both surfaces (this sometimes hard to see on older specimens)

6 4. Bracts at fruiting 36 mm long, obovate to depressed-circular in outline, the margins with several coarse teeth or lobes to below the midpoint ... 1. A. ARGENTEA

Atriplex argentea var. argentea
7 4. Bracts at fruiting 23 mm long, obtriangular to wedge-shaped, the margins entire except for usually 3 teeth along the truncate tip (sometimes also slightly irregular between the teeth) ... 7. A. TRUNCATA

Atriplex truncata
8 1. Pistillate flowers with the bracts fused only toward the base, at maturity becoming more or less uniformly papery or leathery (somewhat spongy-thickened toward the base in A. prostrata), the fruit easily separable from the bracts

9 5. Pistillate flowers of 2 kinds on the same plant (best seen at fruiting), differing in the size or presence of the 2 bracts, these (when present) elliptic-ovate to broadly ovate or nearly circular at fruiting

10 6. Some pistillate flowers lacking bracts but with a minute, 5-lobed calyx, other pistillate flowers with 2 bracts but lacking a calyx, the bracts enlarging to 618 mm long at fruiting ... 2. A. HORTENSIS

Atriplex hortensis
11 6. All pistillate flowers lacking a calyx, both kinds of flowers with 2 bracts; at fruiting some flowers with the bracts 1.52.5 mm long, others with the bracts enlarging to 56 mm long at fruiting ... 3. A. MICRANTHA

Atriplex micrantha
12 5. Pistillate flowers all similar (but sometimes producing fruits with 2 different kinds of seeds), with 2 bracts, these triangular to broadly ovate-triangular or rhombic at fruiting

13 7. Bracts not spongy-thickened, more or less evenly herbaceous; leaves mostly without a pair of basal lobes, when present these loosely angled toward the leaf tip ... 4. A. PATULA

Atriplex patula
14 7. Bracts more or less spongy-thickened toward the base; leaves all or mostly with a pair of basal lobes, these spreading ... 5. A. PROSTRATA Atriplex prostrata
 
 
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