S. latifolia is an erect emergent aquatic plant, an obligate wetland species found from southern Canada to northern and western South America. It is widely cultivated as an ornamental pond plant in Europe and is also introduced in F...
S. latifolia is an erect emergent aquatic plant, an obligate wetland species found from southern Canada to northern and western South America. It is widely cultivated as an ornamental pond plant in Europe and is also introduced in French Polynesia and Hawaii where is considered invasive. S. latifolia is recognized as being potentially invasive due to clonal growth (Weber and Gut, 2004). It can grow aggressively, spreading to form large patches of plants which can span slow-moving streams and form solid stands in artificial waterways (Iverson et al., 1999).
In its native range, S. latifolia has been declared an aquatic weed in Puerto Rico (USDA-ARS, 2009) and is recognized in some areas of North America as a weed by the Southern Weed Science Society (Bryson, 2004).
The Alismataceae has 11 genera and some 95 species, all of which are aquatic, with a cosmopolitan distribution. Sagittaria is one of the larger genera in the Alismataceae, with 20 species. Most of them are found in the New World (Preston and Croft, 1997). Sagittaria latifolia has been divided into two varieties, based upon whether or not the whole vegetative plant is pubescent (Bogin, 1955; Rataj, 1972). However, for Haynes and Holm-Nielsen (1993, 1994) this character alone is insufficient for recognition of the varieties, so it is considered to be a single species (Novelo, 2003; FNA, 2009). S. latifolia Willd. (1805) is the accepted name by IPNI (2009).
Herbs, perennial, to 45 cm, arising from stout, tuberous rhizomes; stolons present; corms present. Root depth, minimum 0.45 cm (USDA-NRCS, 2009). Leaves erect, those submerged, if present, linear and ribbon-like, emersed ones with blades sagittate, lateral lobes as long as terminal one, linear or ovate-deltate, 2-20 cm long, 0.5-12 cm wide; terminal lobe deltate to ovate-deltate or linear, 3-25 cm long, 0.7-35 cm wide, apex acuminate to subobtuse; petioles 20-70 cm long. Inflorescences racemes, rarely panicles, of 3-9 whorls, emersed, 4.5-28.5, (4-23) cm; peduncles 10-59 cm; bracts connate more than or equal to 1/4 total length, elliptic to lanceolate, 3-8 mm, delicate, not papillose; fruiting pedicels spreading, cylindric, 0.5-3.5 cm. Flowers to 4 cm diameter; unisexual (and the plants monoecious or dioecious), lower flowers pistillate, upper ones staminate, and usually with some perfect flowers in the middle, or rarely all flowers perfect, scapes few, 15-70 (-90) cm long, shorter than or slightly longer than leaves, each with 2-7 verticils of flowers, pedicels 0.5-6 cm long, bracts 2-3 per flower, papery, lanceolate to deltate, 0.5-1 (-1.5) cm long, usually gibbous; sepals ovate, 5-10 mm long; petals white, very broadly elliptic, 1-2 cm long, abruptly narrowed into a claw.
Achenes 2.5-4 mm long, dorsal margin winged, beak stout, extending at a right angle from the body, 0.5-1.5 mm long (Wagner et al., 1999; FNA, 2009).
S. latifolia is a native species in the N. American continent and is well distributed throughout southeastern Canada and the eastern United States, being the commonest and most widespread species of the genus Sagittaria, overlapping with Sagittaria cuneata. It is found in temperate and subtropical wetlands throughout the continent and extending south to Central America, Guatemala, Honduras, Nicaragua, Colombia, Ecuador and Venezuela (FNA, 2009; USDA-ARS, 2009; USDA-NRCS, 2009). It is introduced in the Hawaiian Islands (USDA-NRCS, 2009) and naturalized in several European countries.
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.
S. latifolia outside its native range has been reported in Pacific islands and Europe. It has been introduced in French Polynesia (PIER, 2009); in 1916 to Hawaii where it is considered invasive (Stone et al., 1992). In Europe it was reported in Romania in 1931 (DAISIE, 2009), from here to Italy (1940), in the UK in 1941 (Preston and Croft, 1997), Austria in 1950, Germany in 1966 (NOBANIS, 2009) and is reported to be present in Belgium, France, the Czech Republic and Ukraine. In Europe it is established but it is not widely naturalized.
S. latifolia has been introduced for ornamental and amenity purposes and has therefore been intentionally introduced into many countries in Europe. This species has escaped and established populations in the wild (DAISIE, 2009; NOBANIS, 2009); in most cases it has become established in the area in which it was originally planted, but it may be spreading along river banks (Preston and Croft, 1997).
S. latifolia is included in the Western Australian Prohibited List (GIST, 2003), and in New Zealand S. latifolia’s seeds are Regulated Weed Seeds and prohibited from all consignments (MAF Bisosecurity, 2009). In Europe S. latifolia is regulated at the national level for horticultural nurseries (Heywood and Brunel, 2008), so further introductions in these countries are therefore unlikely.
S. latifolia is extremely frequent as an emergent plant on very wet soils, and it is classified as wetland obligate in wetland indicator status in America (U.S. Fish and Wildlife Service, 1988), forming colonies in shallow waters, in long bands following the curves of rivers, ponds and lakes. It is also found in ditches, in open woodlands that are prone to frequent flooding, in swamps, marshes, bogs, seeps and freshwater wetlands, stream-sides, ditches, floodplains, low-lying areas with wet mud, and the borders of lakes or ponds (Hickman, 1993; FNA, 2009). In Europe, it is found in shallow water in lowland and ponds, roadside ditches and at the edge of canals, stream and rivers and wetlands (Preston and Croft, 1997; NOBANIS, 2009). In Hawaii, it is naturalized in low elevation wetlands, slow streams, and taro paddies (Wagner et al., 1999).
S. latifolia is an important perennial herbaceous wetland plant, propagated by rhizomes, corms, or seed (Marburger, 1993; Sutton, 1995). The populations of this clonal aquatic plant are either monoecious or dioecious; both populations exist throughout the species' range in close geographic proximity (Smith, 1894) and the relative pollination success of dioecious versus monoecious populations decreases with increased floral display (Vamosi et al., 2006). One plant can produce up to 20,000 viable achenes and each achene contains a flattened ovate green nutlet (USDA-NRCS, 2002). Exposed mud is required for successful seedling establishment. Germination occurs once the seed coat has been eroded or ruptured, which usually happens during the winter (Kaul, 1985; Wooten, 1971; Muenchow and Delesalle, 1994; Sarkissianet al., 2001). Flowering individuals produce racemes with three flowers at each node. Inflorescences on monoecious plants produce female flowers at basal nodes and male flowers at distal nodes. Because the single-day flowers open from the bottom to the top of the inflorescence, in monoecious populations the inflorescences are protogynous. There is considerable gender variation among populations of S. latifolia (Sarkissian et al. 2001). Plants are self-compatible, clonal, and visited by non-specialist insects including flies, bees, wasps, and butterflies (Muenchow and Delesalle 1994),
In the native range some populations consist of monoecious plants, which usually reproduce vegetatively (Wooten, 1971). In Europe, only clonal monoecious plants are present and there are no reported occurrences of ripe seed or seedlings (Preston and Croft, 1997). Clonal spread occurs through growth of rhizomes and tubers.
Physiology and Phenology
Flowering from summer to autumn (Novelo, 2003; FNA, 2009). Vegetative production peaks in July and aboveground biomass of about 500 +/- 80 g DW/m2 has been reported (Rothman and Bouchard, 2007). From August to October round clusters of seeds (achenes) develop; the seedlings are very abundant in spring and early summer (Kaul, 1985) but by mid-autumn the emergent plant parts die back to the root crown to tubers, which are borne on stolons in the leaf axils. They act as a means of perennation and vegetative spread: a single plant can annually yield up to 40 tubers (USDA-NRCS, 2002). S. latifolia only grows well in freshwater habitats (Martin and Shaffer, 2005). It can germinate; but cannot grow well under low-salinity conditions and in high-salinity conditions the germination decreases, and there is delayed emergence and decreased survival and growth rates (Delesalle and Blum, 1994). The growth is inhibited when ammonia levels are in excess of 200 mg/l (Clarke and Baldwin, 2002) and moist soils to standing water are required for successful revegetation (Sarkissian et al., 2001).
The populations of monoecious and dioecious S. latifolia occur in close geographic proximity but often occupy different types of aquatic habitats and exhibit different life history characteristics: monoecious populations grow in a variety of wetland habitats, including shorelines, creeks, roadside ditches, and ponds associated with agriculture. These habitats are characterized by frequent disturbance and are often ephemeral. In contrast, dioecious populations are primarily restricted to large, permanent wetlands, and lakes (Sarkissian et al., 2001). In addition, the two sexual systems display divergent patterns of plasticity. The corm production increases in monoecious populations and time of flowering (delayed in dioecious populations) and the leaf size generally increases due to the addition of fertilizer; however, this increase is substantially greater in dioecious populations (Dorken and Barrett, 2004b) and it shows significant plasticity for female sex allocation in monoecious populations which flower earlier and produce more flowers, clonal ramets, and corms than dioecious populations (Dorken and Barrett, 2003b).
Extremely frequent as an emergent plant, S. latifolia forms dense colonies on very wet soils that become more open as the species mixes with other species of deeper water levels. In its native range it is associated with pickerel weed (Pontederia cordata), cattails (Typha spp.), sedges, rushes, grasses, and lesser bur-reed (Sparganium americanum). In the UK, it has been reported to be associated with Glyceria maxima, Lagarosiphon mayor, Myriophyllum aquaticum and Nymphaea alba (Preston and Croft, 1997) and also with reeds and tall sedges (BiolFlor, 2009).
This broadleaf emergent thrives in finely textured unconsolidated organic and silty wet soils that are submerged in water for most or all of the year. S. latifolia thrives in fresh water 15-30 cm deep, and tolerates water up to 50 cm deep, with few draw-downs and full sun exposure, (USDA-NRCS, 2002), and with pH ranging from 5.9 to 8.8 (USDA-NRCS, 2009). It can withstand turbid conditions, and it does not tolerate severe sediment deposition. The plant has strong roots and can survive through wide variations of the water level, slow currents and waves. It displays an affinity for high levels of phosphates and hard waters (USDA-NRCS, 2009). It is found from sea level up to more than 2000 m altitude (FNA, 2009; Missouri Botanic Garden, 2009).
Center et al. (1999) reported four native plant-feeding insects in USA found in Sagittaria spp. The most commonly encountered are arrowhead weevils, Listronotus spp. (Coleoptera: Curculionidae: Brachycerinae: Rhytirrhinini), which feed on and breed in various species of Sagittaria (Alismataceae). The larvae feed and develop within the flower stalks (peduncles). Adults feed on the flowers and fruits. The adults of pickerel weed weevil, Onychylis nigrirostris (Coleoptera: Curculionidae: Curculioninae: Erirhinini) feed on the surfaces of the leaves. The waterlily aphid, Rhopalosiphum nymphaeae (Homoptera: Aphididae) is extremely destructive in aquatic gardens and nurseries and is known to transmit at least five plant viruses. Waterlily leaf beetle, Pyrrhalta (=Galerucella) nymphaeae (Coleoptera: Chrysomelidae: Galerucinae) adults feed on the leaves. The last three species are not specific to the genus Sagittaria.
Another natural enemy is the smut fungus: up to five species of the genus Doassansia have been reported to attack S. latifolia, including Doassansia sagittariae. The fungi develop in leaves, but the general growth of the host plants is not noticeably affected (Piepenbring and Hagedorn, 2002). Another natural enemy is the nutria which causes deleterious effects due to high herbivory on S. latifolia and S. platyphylla (Grace and Ford 1996; Evers et al., 1998).
The tubers can be dispersed by water in streams and rivers.
Vector Transmission (Biotic)
The seeds could be dispersed by animals.
There are no reports that this species has been accidentally introduced.
S. latifolia has been introduced for ornamental and amenity purposes and has therefore been intentionally introduced to many countries in Europe. This species has escaped and established populations in the wild (DAISIE, 2009; NOBANIS, 2009).
The starchy tuber of S. latifolia has been used since ancient times as a food and trading commodity by native Americans, who call it wapato (Kuhnlein and Turner, 1991; Darby, 1996; Spurgeon, 1996), as well as by Chinese and Japanese immigrants in California (Bogin, 1955). The Chinese, on coming to California, used it for food and may have cultivated it to some extent. S. latifolia is extensively cultivated in the San Francisco Bay area in California to supply the Chinese markets, and the tubers are commonly to be found on sale. This is believed to have extended the plant’s range into the southern part of the state (Mason, 1957). It is also used as a medicinal plant.
S. latifolia tolerates and assimilates high levels of nutrients, particularly phosphorus (Boyd, 1970). For this reason S. latifolia is often selected for use in municipal and domestic wastewater treatment systems, constructed wetlands and stormwater runoff treatment, and for wetland enhancement, restoration, and creation (Marburger, 1993). Muskrats eat the whole plant including tubers, leaves, and seeds. For canvas-back duck (Aythya valisineria), S. latifolia and Cyperus esculentus make up 94% of its diet (Hohman et al., 1990).
This species is important as food and cover for aquatic animal life (Thunhorst, 1993). The emergent and submerged leaves are used as shelter for different species of fish and macroinvertebrates (USDA-NRCS, 2002). These dense patches are important spawning and nursery grounds for some species of fish. Many shorebirds, other waterfowl, and aquatic mammals like the otter, beavers, North American porcupines and muskrat eat the whole plant including tubers, leaves, and seeds.
In its native range, S. latifolia could be confused with S. cuneata. Both species have white or bluish tubers, which are edible. A diagnostic feature distinguishing the two species is the beak on the fruit of S. cuneata, which is ascending to erect and <0.5 mm; the beak on the fruit of S. latifolia is spreading and 1-2 mm (USDA-NRCS, 2002). In Europe, it may be confused with the native S. sagittifolia (Preston and Croft, 1997). It can be identified to genus using vegetative characters but ripe fruit is required for identification to species; the alien taxa apparently rarely produce ripe fruit. Consequently, it is rarely possible to identify them with confidence. In some cases, it may not be possible to separate S. latifolia from S. sagittifolia without flowers; however, the extremely fine long leaves apparently do not occur in S. sagittifolia. When in flower, S. sagittifolia has entirely white petals and yellow anthers, whereas in S. latifolia there is a purple spot at the base of the petal (Lansdown, 2008).
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.
In Europe S. latifolia is regulated at the national level for horticultural nurseries, being considered an ecological threat, and cultivation, sale, exchange, transport, cultivation and detention in a confined place are prohibited so as to prevent their introduction in the wild (Heywood and Brunel, 2008).
As Marburger (1993) suggests, there is still much to be learned about S. latifolia’s ecology and physiology as regards its use for wetland restoration; and overall it is necessary to know more about its invasive character in its introduced range and the precise nature of its impacts.
NOBANIS, 2009. Sagittaria latifolia. In: North European and Baltic Network on Invasive Alien Species. Gateway to information on Invasive Alien species in North and Central Europe, http://www.nobanis.org