Cotula australis |
Cotula |
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Australian cotula, Australian water-buttons, brass buttons |
cotula, water-buttons |
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Habit | Annuals, 2–10(–25+) cm. | Annuals or perennials, 2–25[–50+] cm (sometimes aromatic). | ||||
Stems | branched ± throughout, ± strigillose to villous, glabrescent. |
usually 1, erect or prostrate to decumbent or ascending (sometimes rooting at nodes), usually branched, glabrous or ± strigillose to villous (hairs mostly basifixed). |
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Leaves | petiolate or sessile; blades obovate to spatulate, 2–3-pinnately lobed (ultimate lobes narrowly spatulate to linear), (1–)2–3(–6) cm. |
usually mostly cauline [basal]; alternate [opposite]; petiolate or sessile; blades obovate or spatulate to lanceolate or linear, sometimes 1–3-pinnately [palmati-pinnately] lobed, ultimate margins entire or irregularly toothed, faces glabrous or ± strigillose to villous [lanate] (hairs mostly basifixed). |
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Involucres | 3–4(–6) mm diam. |
broadly hemispheric to saucer-shaped, 3–12+[–15+] mm diam. |
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Receptacles | flat to convex [conic], epaleate (sometimes ± covered with persistent stalks of florets). |
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Ray florets | 0 (peripheral pistillate florets 8–80+ in 1–3+ series; corollas 0). |
0 [5–8+, pistillate, fertile; corollas white] (peripheral pistillate florets 8–80+ in 1–3+ series; corollas usually none). |
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Disc florets/ |
ochroleucous to pale yellow, 0.5–0.8 mm. |
12–200+[–600+], bisexual, fertile [functionally staminate]; corollas ochroleucous or yellow, tubes ± cylindric (bases sometimes adaxially saccate), throats abruptly ampliate, lobes (3–)4, ± deltate (sometimes one larger than others, usually each with central resin canal). |
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Phyllaries | 13–22+ in 2–3 series, subequal (apices brown). |
persistent, 13–30+ in 2–3+ series, margins and apices (colorless, light to dark brown, or purplish) scarious. |
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Heads | disciform [discoid or radiate], borne singly (peduncles sometimes dilated). |
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Cypselae | outer stalked, 1–1.2 mm, ± winged, faces ± papillate; inner sessile, 0.8–1 mm, not winged, not papillate. |
obovoid to oblong, ob-compressed or -flattened, ribs 2, lateral, sometimes becoming wings, faces ± papillate (pericarps relatively thin, sometimes with myxogenic cells and/or 2 lateral resin sacs); pappi 0. |
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x | = 10. |
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2n | = 36, 40. |
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Cotula australis |
Cotula |
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Phenology | Flowering Jan–Sep. | |||||
Habitat | Disturbed sites | |||||
Elevation | 0–800 m (0–2600 ft) | |||||
Distribution |
AZ; CA; FL; ME; OR; TX; South America; Australia; Africa [Introduced in North America; also introduced in Northern Hemisphere: Mexico (Baja California)]
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s Old World [Introduced in North America; introduced also (perhaps some native) in Mexico, South America, s Oceanic Islands] |
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Discussion | Species 55 (2 in the flora). Some species of Cotula are widely naturalized. F. Hrusa et al. (2002) reported Cotula mexicana (de Candolle) Cabrera as established on golf courses in California; it is similar to C. australis and differs in leaf blades mostly 1-pinnate, receptacles pilose, and disc florets functionally staminate. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 19, p. 544. | FNA vol. 19, p. 543. | ||||
Parent taxa | Asteraceae > tribe Anthemideae > Cotula | Asteraceae > tribe Anthemideae | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Anacyclus australis | |||||
Name authority | (Sieber ex Sprengel) Hooker f.: Fl. Nov.-Zel. 1: 128. (1852) | Linnaeus: Sp. Pl. 2: 891. (1753): Gen. Pl. ed. 5, 380. (1754) | ||||
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