Atriplex covillei |
Atriplex linearis |
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Coville's orach |
slenderleaf saltbush, thinleaf fourwing saltbush |
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Habit | Herbs, spreading, 1–4(–5) dm and as broad. | Shrubs dioecious, erect, mainly 10–25 dm; branchlets slender, terete. |
Stems | terete, sparsely scurfy when young. |
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Leaves | 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. |
sessile; blade narrowly linear-elliptic, 10–50 × 2–3 mm, firm, revolute, often acute apically. |
Staminate flowers | in sessile glomerules in distal axils, often mixed with pistillate ones, staminate calyx deeply 5-cleft; lobes obtuse, not appendaged. |
in glomerules borne in slender interrupted mostly paniculate spikes. |
Pistillate flowers | with calyx of (1–)3(–5) hyaline sepals. |
paniculate or in few-flowered axillary glomerules. |
Seeds | dark reddish brown, 1–1.5 mm. |
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Fruiting | 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. |
bracteoles sessile or subsessile, lanceolate to ovate, 4–6 mm, about as wide, each bract with a pair of thin wings 3 mm broad or less, irregularly dentate or laciniate, free tips of bracts much exceeding the wings. |
2n | = 18. |
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Atriplex covillei |
Atriplex linearis |
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Phenology | Flowering summer–fall. | Flowering spring–fall. |
Habitat | Mixed saltbush-greasewood, rabbitbrush, warm desert shrub, and salt grass communities in saline substrates | Saline deserts, with shadscale, Canotia, Yucca, Opuntia, Rhus, and Eriogonum |
Elevation | 800-1700 m (2600-5600 ft) | 0-800 m (0-2600 ft) |
Distribution |
CA; NV; OR |
AZ; CA; nw Mexico (Baja California, Sonora)
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Discussion | 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.) |
Specimens of Atriplex canescens var. macilenta resemble A. linearis. The taxa have been placed together by some previous workers. Nevertheless, the stems of A. linearis are consistently more slender, the leaves proportionally narrower, and the bracts, though smaller, more closely simulate those of A. canescens. Its diploid nature signals a different evolutionary pathway than that for most of A. canescens, considered broadly. Narrow leaves occur within A. canescens, in the broad sense, sometimes with geographic correlation, sometimes not. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 4. | FNA vol. 4, p. 381. |
Parent taxa | Chenopodiaceae > Atriplex > subg. Obione > sect. Covilleiae | Chenopodiaceae > Atriplex > subg. Pterochiton |
Sibling taxa | ||
Synonyms | Endolepis covillei | A. canescens subsp. linearis, A. canescens var. linearis |
Name authority | (Standley) J. F. Macbride: Contr. Gray Herb. 53: 11. (1918) | S. Watson: Proc. Amer. Acad. Arts 24: 72. (1889) |
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