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Practical ecological knowledge for the temperate reader. |
Family: Asteraceae (Aster) [E-flora]
"Waterbutton (Cotula coronopifolia) has long been regarded as native, but by the late 1990s was increasingly being listed in various Floras as an exotic.... I will use this species to show how dubious the unwelcome brand of exotic origin can sometimes be, and also present evidence from three overlooked papers that shows waterbutton was already widespread in south-eastern Australia thousands of years ago, and possibly elsewhere.
Waterbutton was a familiar plant around the Port Jackson settlement where it was first collected by Robert Brown, just after the turn of the nineteenth century. He had already seen the same species in southern Africa on the journey here, so included it on a list of 29 introduced and possibly introduced species for the Port Jackson area. Of these, waterbutton was one of the two species he tagged with a question mark, because its wide distribution around Port Jackson (presumably much wider than for plants which were obviously recent introductions) suggested it had long been established there.
As exploration of Australia continued over the next half century, waterbutton was found in wetlands both inland and along most of our southern coasts. If it had been a recent introduction at Port Jackson, it must have been one of the fastest spreading weeds on record, yet it has not been observed to spread into any new area since those times. In comparable areas of the Northern Hemisphere where it is definitely introduced, waterbutton has spread at a much slower rate, taking centuries to achieve its present and still expanding range. Waterbutton is also native to the southern parts of South America.
...If waterbutton is native to all these continents, separated by oceanic distances, or even just South Africa and South America, how did it spread? As this species will tolerate salinities nearly twice that of seawater, and broken-off pieces I have floated in seawater have started putting out roots after four months, it isn’t hard to see how living pieces of this plant could survive a sea journey. Stranger and much more delicate things have floated across the Indian Ocean, not least two sub-fossil Aepyornis eggs from Madagascar (the largest of all eggs known) which washed up undamaged in Western Australia. Broken-off pieces of waterbutton are far less delicate and vastly more common, as can be seen along some of our southern coasts after a south-westerly storm." [Romanowski]
"Cotula coronopifolia is a ANNUAL/PERENNIAL growing to 0.1 m (0ft 4in) by 0.5 m (1ft 8in). It is hardy to zone (UK) 7. It is in flower from July to August. The species is hermaphrodite (has both male and female organs) and is pollinated by Insects. Suitable for: light (sandy), medium (loamy) and heavy (clay) soils. Suitable pH: acid, neutral and basic (alkaline) soils. It cannot grow in the shade. It prefers moist or wet soil." [PFAF]
"Habitat / Range: "Wet tidal flats and marshes in the lowland zone; infrequent on the north coast and islands, common in SW BC, known from SE Vancouver Island and the adjacent mainland; introduced from South Africa." [IFBC-E-flora]
Status: Exotic [E-flora]
Cultivation & Propagation
"A marginal plant for the shallow edges of ponds, bog gardens and waterside plantings[200], it succeeds in ordinary soil[1]. Plants are short-lived perennials[188]. The whole plant, when handled, releases an aromatic, pungent smell[245]." [PFAF]
"Seed - where possible, sow the seed as soon as it is ripe in a cold frame. Stand the pot in 2cm of water in order to keep the soil moist. When they are large enough to handle, prick the seedlings out into individual pots and plant them out into their permanent positions in late spring or early summer. Division of rooted pieces in the spring." [PFAF]
"Annual, perennial herb, sometimes aromatic, glabrous or minutely strigose to long-soft-hairy. Stem: prostrate to erect. Leaf: generally mostly cauline, alternate, petioled or sessile, linear or lanceolate to obovate, entire to toothed or 1–3-pinnately lobed. Inflorescence: heads disciform [discoid or radiate], 1, peduncled; involucre widely hemispheric to saucer-shaped; phyllaries persistent, 13–30+ in 2–3+ series, margins and tips scarious; receptacle flat to convex [conic], epaleate, sometimes ± covered with persistent fruit stalks. Pistillate flower: 8–80 in 1–3+ series; corolla generally 0 [ray flowers 5–8+, pistillate, fertile; corolla white]. Disk flower: 12–200+ bisexual [staminate]; corolla very short, yellow or ± white, tube widely cylindric, << throat, ± expanded at base, sometimes enveloping top of ovary, lobes generally 4; stamen tip rounded-triangular; style tips truncate, brush-like. Fruit: obovoid to oblong, compressed front-to-back, 2-ribbed or -winged, faces ± papillate; pappus 0.
55 species: mostly southern hemisphere in Old World. (Greek: cup) [Watson 2006 FNANM 19:543–544] Cotula mexicana (DC.) Cabrera <Noxious weed> (annual, leaves generally 1-pinnate, disk flowers staminate), a noxious weed of California golf courses, expected in wildlands." [Jepson]
"Cotula. (Asteraceae) These are creeping daisies found from the water’s edge to moderately deep waters, depending on species. Waterbutton (C. coronipifolia) is presently treated as a possible exotic in some contemporary Floras but there is good evidence that it has been in Australia for many thousands of years, as has been discussed in Chapter 4. There are also several smaller native species but only waterbutton is a significant habitat species, particularly in slightly saline wetlands. All species are readily propagated by seed sown onto wet soils, by division, or for waterbutton from elongated, submerged cuttings." [Romanowski]
Information on Non-local Species
"Two further C-methylated flavonols have been found in glycosidic combination, ... and the 7-galactosyl(1!2)rhamnoside of 5,7-dihydroxy-6,8-di-C-methyl-3-methoxyflavone from Cotula anthemoides (Compositae)." [Andersen FCBA]
"Luteolin 5-0-glucoside is known from a Cotula species (Glennie and Harborne, 1971)" [Bohm FSF]
"Glennie and Harborne (1971) reported quercetin and isorhamnetin 5-0-glucosides from C. australis and C. barbata, kaempferol 5-0-glucoside from C. goughensis, and quercetin and luteolin 5-0-glucosides from C. turbinata. Cotula cinerea accumulates apigenin 7-0-rhamnoside, luteolin 7-0-mono- and diglucosides, 6-hydroxyluteolin 7-0-glucoside, several quercetin glycosides, and quercetagetin- 3,6,7-trimethyl ether (chrysosplenol-D) (Ahmed et aI., 1987a). Mahran et aI. (1975) had reported kaempferol and quercetin glycosides from C. cinerea." [Bohm FSF]
Cotula cinerea
Aphid Host Plant
Journals of Interest
Related Genera
"Leptinella consists of 33 species that occur in New Guinea, Australia including Tasmania, and New Zealand including the subantarctic islands. One of the species also occurs in southern South America. Several species of Leptinella were formerly considered as belonging to Cotula. One of these, C. squalida, a New Zealand taxon, was reported to accumulate isorhamnetin (Greger, 1969)." [Bohm FSF]