Atriplex argentea |
Atriplex covillei |
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maidenhair spleenwort, silver orach, silver orache, silver saltbush, silverscale, silverscale orache, silverscale saltbush, silvery orache |
Coville's orach |
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Habit | Herbs, simple or freely branched, 0.5–6 dm; branches rather stout, angled, scurfy when young. | Herbs, spreading, 1–4(–5) dm and as broad. | ||||||||||||||||
Stems | terete, sparsely scurfy when young. |
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Leaves | often opposite proximally, petiolate or distal bracteate ones subsessile, blade lance-ovate, lanceolate, deltoid, or cordate, 5–75 × 4–50(–75) mm, base subhastate or obtuse to acute, margin entire or essentially so, sometimes closely repand-dentate, apex obtuse to acute or rounded, scurfy (glabrous). |
petiole to 1/2 as long as blade (becoming subsessile distally); blade green or finally stramineous, (10–)20–50 × 6–30 mm, firm, base abruptly acute to narrowly cuneate, apex acute to attenuate, sparsely scurfy. |
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Flowers | in axillary glomerules and terminal, interrupted spikes. |
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Staminate flowers | borne in distal axils, or in short dense spikes or panicles, or intermixed with pistillate, with 4–5-parted calyx. |
in sessile glomerules in distal axils, often mixed with pistillate ones, staminate calyx deeply 5-cleft; lobes obtuse, not appendaged. |
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Pistillate flowers | with calyx of (1–)3(–5) hyaline sepals. |
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Seeds | brown, 1.5–2 mm wide; radicle superior or lateral. |
dark reddish brown, 1–1.5 mm. |
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Fruiting | bracteoles sessile, subsessile, or stipitate (stipe 0.5–5 mm), cuneate-orbicular, (2.5–)4–11.2 × 2–8.8(–14) mm, margin foliaceous below apex, subentire or dentate to laciniate, face smooth, tuberculate, or crested, processes sometimes again toothed, teeth then aligned with axis of process. |
bracteoles sessile or stipitate, 6–12 × 4–7 mm, margin mostly 3-lobed, with elongate terminal lobe triangular to lanceolate, 2 short rounded lobes at base or sides merely rounded at base, united to beyond middle. |
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2n | = 18, 36, 54. |
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Atriplex argentea |
Atriplex covillei |
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Phenology | Flowering summer–fall. | |||||||||||||||||
Habitat | Mixed saltbush-greasewood, rabbitbrush, warm desert shrub, and salt grass communities in saline substrates | |||||||||||||||||
Elevation | 800-1700 m (2600-5600 ft) | |||||||||||||||||
Distribution |
AZ; CA; CO; ID; KS; MT; ND; NE; NM; NV; OK; OR; SD; TX; UT; WA; WY; AB; BC; MB; SK; Mexico
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CA; NV; OR |
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Discussion | Varieties 5 (5 in the flora). Herbarium materials have tended to represent a catchall for annual specimens not readily assignable to other taxa. Indeed, the distinguishing features of the Atriplex argentea complex are shared singly and often in combination with other taxa. Only by use of combinations of features can this taxon be defined. Those features, with much variation, center around the broad, typically ovate to deltoid leaf blades (often definitely 3-veined) and more-or-less compressed, sessile to subsessile (or short stipitate), fruiting bracteoles on which the marginal processes, or teeth, are mainly aligned with the plane compression, and with the faces quite smooth to variously appendaged. Still some specimens are apparently intermediate with other species, especially with the closely allied A. saccaria, with which it is at least partially sympatric. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Endolepis covillei was treated within the synonymy of Atriplex phyllostegia (Torrey) S. Watson by H. M. Hall and F. E. Clements (1923). H. C. Stutz et al. (1993) placed Atriplex covillei within Endolepis, based in large part on the presence of a perianth subtending the pistil within the fruiting bracteoles and on the lack of Kranz anatomy in the leaves. The pattern of venation is, nevertheless, very similar to that in species with Kranz anatomy. The presence of perianth scales in the pistillate flowers of A. covillei has been regarded as evidence of relationship with A. suckleyi. Despite placement of these taxa within Endolepis by Stutz et al. Atriplex covillei is possibly more closely allied to the morphologically similar and partially sympatric A. phyllostegia than it is to strongly dissimilar and the distantly disjunct A. suckleyi. Stutz and his associates placed great emphasis on the presence of reduced perianth segments subtending the pistil within the fruiting bracteoles of A. covillei. Calyces per se, otherwise known only in A. suckleyi and A. pleiantha, probably have arisen independently. Their presence does not necessarily indicate a close relationship. Stutz et al. pointed to other differences aside from the calyx of the pistillate flowers, and it is apparent that the two entities can stand as distinct species. To segregate A. covillei within a separate genus and to ally it with a species to which its relationships are obscure at best, stretches logic beyond reason. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 4. | FNA vol. 4. | ||||||||||||||||
Parent taxa | Chenopodiaceae > Atriplex > subg. Obione > sect. Obione > subsect. Argenteae | Chenopodiaceae > Atriplex > subg. Obione > sect. Covilleiae | ||||||||||||||||
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Subordinate taxa | ||||||||||||||||||
Synonyms | Obione argentea | Endolepis covillei | ||||||||||||||||
Name authority | Nuttall: Gen. N. Amer. Pl. 1: 198. (1818) | (Standley) J. F. Macbride: Contr. Gray Herb. 53: 11. (1918) | ||||||||||||||||
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