Salsola soda |
Salsola |
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alkali Russian thistle, oppositeleaf Russian thistle |
Russian-thistle, salsovie, saltwort, soude, tumbleweed |
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Habit | Herbs, 5–70 cm, glabrous. | Herbs, annual, or subshrubs [shrubs and small trees], glabrous, or ± pubescent or hispid. | ||||||||||||||||||||||||
Stems | erect or ascending, branched from base or nearly so; branches straight or slightly arcuate (proximal ones sometimes almost prostrate). |
erect, ascending, or prostrate, branched (rarely simple), not jointed, not armed, not fleshy. |
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Leaves | (especially proximal ones) mostly opposite; blade linear, usually more than 1.5 mm wide in herbarium specimens, fleshy, distinctly swollen or ovate at base, apex mucronulate, not spinose. |
mostly alternate (rarely opposite, especially proximal ones), sessile; blade lanceolate, linear, or filiform to subulate, semiterete, margins entire basally, apex obtuse, soft and subspinescent or narrowed to spine or soft bristle. |
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Inflorescences | distinctly interrupted, 1-flowered; bracts alternate or almost opposite, not imbricate, horizontally reflexed at maturity, swollen at base, abruptly narrowing into mucronulate nonspinose apex. |
spicate, flowers solitary in axils of bracts or reduced distal leaves (rarely 2–3-flowered with lateral flowers poorly developed); bracts ovate-lanceolate, spine-tipped. |
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Flowers | bracteoles distinct, not adnate to perianth segments; perianth segments wingless or with rudimental triangular tubercles at maturity, margins crenate or pectinate-ciliate apically, glabrous; fruiting perianth ca. 3–6(–7) mm diam. 2n = 18. |
bisexual, with 2 bracteoles; perianth segments persistent, 5, covering utricle at maturity, often developing transverse, dorsal, membranous or ± coriaceous wing (sometimes only 2–3 segments winged, sometimes wingless or nearly so); stamens 5; styles and stigmas 2 (or 3). |
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Fruits | utricles, covered by perianth segments at maturity; pericarp adherent. |
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Seeds | usually horizontal, orbicular; seed coat black or brown; perisperm absent. |
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x | = 9. |
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Salsola soda |
Salsola |
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Phenology | Flowering spring–summer. | |||||||||||||||||||||||||
Habitat | Coastal and disturbed saline habitats | |||||||||||||||||||||||||
Elevation | 0-50 m (0-200 ft) | |||||||||||||||||||||||||
Distribution |
CA; Eurasia; n Africa [Introduced in North America; introduced in South America]
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almost worldwide; Mediterranean region; arid and coastal zones of Eurasia; n Africa; e Africa; s Africa [Introduced in North America] |
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Discussion | Salsola soda can be expected to spread in California, or to appear in inland or coastal saline habitats in southern states. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Species ca. 130 (6 in the flora). In this treatment, a rather broad and traditional generic concept is accepted for Salsola, including Caroxylon and other segregate genera. It is evident that Salsola in the traditional sense should be regarded as a group of genera rather than a natural monophyletic genus. V. I. Pyankov et al. (2001) recently discussed phylogenetic relationships inferred from parsimony analysis of nucleotide sequences of the internal transcribed spacer regions (ITS) of the 18S–26S nuclear ribosomal DNA of 34 species of Salsola and related genera (Halothamnus Jaubert & Spach, Climacoptera Botschantzev, Girgensohnia Bunge, Halocharis Moquin-Tandon, and Haloxylon Bunge) and four species from representative outgroups (tribes Camphorosmeae and Atripliceae). The study confirmed that Salsola sensu lato is polyphyletic, with several currently recognized related genera rooted within the group. Results of the V. I. Pyankov et al. study also contradict V. P. Botschantzev’s (1969) hypothesis of a South African origin of Salsola sensu lato and place the “cradle” of the genus in central Asia. A comparative taxonomic and phytogeographic analysis (S. L. Mosyakin 2002) also suggests the place of origin of the Salsola generic aggregate is somewhere in the Tethyan region of south-central Asia (probably northern coasts of the ancient Tethys, or adjacent inland lacustrine habitats). Almost all North American taxa belong to Salsola sensu stricto. Species of Salsola sect. Caroxylon (Thunberg) Fenzl, which is represented in North America only by the introduced S. vermiculata, may be recognized in the distinct genus Caroxylon Thunberg following a comprehensive study of the group worldwide. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 4, p. 402. | FNA vol. 4. | ||||||||||||||||||||||||
Parent taxa | Chenopodiaceae > Salsola | Chenopodiaceae | ||||||||||||||||||||||||
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Subordinate taxa | ||||||||||||||||||||||||||
Name authority | Linnaeus: Sp. Pl. 1: 233. (1753) | Linnaeus: Sp. Pl. 1: 222. (1753): Gen. Pl. ed. 5, 104. (1754) | ||||||||||||||||||||||||
Web links |