Christella dentata (soft fern)
Index
- Pictures
- Identity
- Summary of Invasiveness
- Taxonomic Tree
- Notes on Taxonomy and Nomenclature
- Description
- Plant Type
- Distribution
- Distribution Table
- History of Introduction and Spread
- Risk of Introduction
- Habitat
- Habitat List
- Host Plants and Other Plants Affected
- Biology and Ecology
- Climate
- Latitude/Altitude Ranges
- Air Temperature
- Soil Tolerances
- Means of Movement and Dispersal
- Pathway Causes
- Pathway Vectors
- Impact Summary
- Threatened Species
- Risk and Impact Factors
- Uses List
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Gaps in Knowledge/Research Needs
- References
- Organizations
- Contributors
- Distribution Maps
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Top of pagePreferred Scientific Name
- Christella dentata (Forssk.) Holttum
Preferred Common Name
- soft fern
Other Scientific Names
- Aspidium molle Sw., J. Bot. (Schrader) 1800: 34 (1801)
- Aspidium nymphale (G. Forst) Schkuhr (1804)
- Christella dentata var. caespitosa Holttum (1986)
- Cyclosorus dentatus (Forssk.) Ching
- Cyclosorus nymphale (G. Forst) Ching (1941)
- Cyclosourus nymphalis (G.Forst.) Ching
- Dryopteris dentata (Forssk.) C. Chr. (1920)
- Dryopteris molle (Sw.) Hieron (1907)
- Dryopteris nymphalis (G. Forst.) Copel., 59:46 (1929 [1929])
- Nephrodium dentatum (Forssk.) Kümmerle
- Nephrodium molle (Sw.) R.Br. (1810)
- Nephrodium nymphale (G. Forst) Desv. (1827)
- Nephrodium remotum Heward (1842)
- Polypodium dentatum Forssk (1775)
- Polypodium molle Jacq. (1791)
- Polypodium nymphale G. Forst. (1786)
- Thelypteris dentata (Forssk.) E.P. St. John
- Thylepteris nymphalis (G. Forst) C. F. Reed (1968)
International Common Names
- English: downy maiden fern; downy shield fern; downy wood fern; tapering tri-vein fern
- Spanish: helecha
Local Common Names
- Cuba: helecho
Summary of Invasiveness
Top of pageC. dentata is a small fern widespread throughout the tropics and appears to be introduced in Hawaii and the Americas, where it was collected for the first time only relatively recently, having probably established prior to 1900 (Strother and Smith, 1970; Wagner, 1972). Elsewhere in the Pacific it is well established but its status as an introduced species is debated. With long distance dispersal (100s of kilometers) being possible via dispersal of its spores, it is believed to have arrived in New Zealand under its own volition.
Throughout its range it has a tendency to hybridize with other congeners, including other weeds like C. parasitica (=Cyclosorus parasiticus) in Guam, Hawaii and Taiwan, and the endemic C. cyatheoides in Hawaii, and even species from other genera such as Pneumatopteris afra (Fosberg and Sachet 1981; Quansah and Edwards 1986; Palmer 2003). In addition it can be difficult to tell C. dentata apart from some other congeners (Wagner 1950; Brownlie 1959; Lange et al. 1999).
In Hawaii it can form dense stands in disturbed sites, where it can outcompete some native species (J Beachy, US Fish and Wildlife Service, personal communication, 2010a, 2010b, 2010c). It can be an early colonizer after invasive pigs disturb a site (C Buddenhagen, Florida State University, personal observation).
C. dentata is not invasive in New Zealand. Of the two forms present (see Biology and Ecology), the 'true' form occurs only in a few very restricted places in northern New Zealand and is very rare. The thermal form, although more abundant, shows no sign of spreading out from its specialized habitat to other parts of the country. In New Zealand the 'true' C. dentata is regarded as 'Nationally Critical', whilst the other form is deemed 'At Risk'.
Taxonomic Tree
Top of page- Domain: Eukaryota
- Kingdom: Plantae
- Phylum: Pteridophyta
- Class: Filicopsida
- Family: Thelypteridaceae
- Genus: Christella
- Species: Christella dentata
Notes on Taxonomy and Nomenclature
Top of pageChristella dentata (Forssk.) Brownsey & Jermy has been in use for this species since 1973, and much of the existing literature refers to this name (Brownsey and Jermy, 1973). However, in North America and elsewhere Thelypteris dentata (Forssk.) E.P. St. John is still applied to this taxon (USDA, 2012).
It appears though that the genus Christella Léveillé is not monophyletic, and is best subsumed within Cyclosorus, making Cyclosorus dentatus (Forssk.) Ching the preferred name under modern systematic standards (Smith et al., 2006; Evenhuis and Eldredge, 2011; He and Zhang, 2012). All these names are derived from the basionym: Polypodium dentatum Forsskål 1775.
Several common characters exhibit continuous variation across generic boundaries in the clade containing Christella, and some taxa currently within Christella are polyphyletic (He and Zhang, 2012). Christella could be made monophyletic if the few taxa that are polyphyletic were dropped and placed elsewhere; such a decision may be justifiable on the basis of morphological and or molecular (DNA) differences (He and Zhang, 2012). It is worth noting that the type specimen (from Yemen) is unhelpful because it consists of a single portion of the middle of a frond, and so does not show the critical features people traditionally use to define the species (P de Lange, personal communication). Unless this is resolved, understanding when a Christella specimen is naturalized or indigenous anywhere in the Pacific or New World where that name is used is likely to be difficult (Brownlie, 1959).
Given the possibility of Christella becoming monophyletic again, and in view of the fact that The Plant List (2013) lists Christella dentata as a preferred name and Cyclosorus dentatus as a synonym, this datasheet uses the name Christella dentata as the preferred scientific name.
Description
Top of pageStems short-creeping, 4-6 mm in diameter. Leaves often somewhat dimorphic, evergreen, often closely placed, 50-150 cm, fertile, with longer petioles and more contracted pinnae. Petiole often purplish brown, 15-50 cm by 3-6 mm at the base with brown, linear-lanceolate, hairy scales. Blade (25-) 40-100 cm, 1-4(-6) proximal pairs of pinnae reduced, blade gradually tapered to pinnatifid apex. Pinnae 7-17 by 1-3 cm, incised 1/2-3/4 of width; segments rounded at apex, basal acroscopic segment of proximal pinnae often auriculate; proximal pair of veins from adjacent segments united at obtuse angle below sinus with excurrent vein 2-4 mm. Indument abaxially of uniformly short hairs 0.1-0.2 mm on costae, veins, and blade tissue; veins adaxially with stouter hairs, also with hairs 0.1-0.2 mm on blade tissue. Sori round, medial to supramedial; indusia tan, pubescent, hairs 0.1-0.3 mm; sporangial stalks with orangish, stalked glands (Flora of North America, 1993).
Distribution
Top of pageC. dentata is native to the Old World tropics (widespread in Asia and Africa) and temperate parts of Australia and New Zealand (McCarthy, 1998), but is adventive in North and Central America. It has been described as having a tropical cosmopolitan distribution (Iwatsuki, 1963), but it also occurs in subtropical sites that are frost-free or nearly so, perhaps surviving a few frosts a year in northern Florida (GBIF, 2012).
C. dentata was first recorded in Japan in the 1950s and has since spread northward (possibly as a greenhouse contaminant) at a rate of 3 km per year, persisting through the winters probably as a result of urban heat islands (Murakami et al., 2007). In Hawaii the species was collected much earlier and was probably introduced in and established by the late 1800s (MacCaughey, 1918; Wagner, 1950).
It is not clear whether the two forms of C. dentata present in New Zealand (see Biology and Ecology) arrived within historic time or whether they have been established there rather longer, although the species was recorded early in the country's history, so it seems unlikely to have been introduced (P Brownsey, Museum of New Zealand, personal communication). There is similar uncertainty over C. dentata in Fiji.
C. dentata is regarded as native in Lord Howe Island, Norfolk Island, Tonga and Tahiti, although one publication suggests it is introduced in Tahiti (Iwatsuki 1963; Rodd and Pickard 1983; Murdock and Smith 2003; Orchard, 1994; Meyer et al., 2009). It has also been recorded from New Caledonia, Vanuatu, Samoa and the Cook Islands.
Distribution Table
Top of pageThe 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.
Last updated: 17 Dec 2021Continent/Country/Region | Distribution | Last Reported | Origin | First Reported | Invasive | Reference | Notes |
---|---|---|---|---|---|---|---|
Africa |
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Angola | Present | Native | |||||
Benin | Present | Native | Atacora | ||||
Burkina Faso | Present | Native | |||||
Burundi | Present, Widespread | Native | Bubanza Bururi | ||||
Cabo Verde | Present | Native | |||||
Cameroon | Present | Native | |||||
Central African Republic | Present | Native | |||||
Comoros | Present | Native | |||||
Congo, Democratic Republic of the | Present | Native | |||||
Congo, Republic of the | Present | Native | |||||
Côte d'Ivoire | Present, Widespread | Native | |||||
Equatorial Guinea | Present | Native | |||||
Eswatini | Present, Localized | Native | |||||
Ethiopia | Present | Native | |||||
Gabon | Present, Widespread | Native | |||||
Ghana | Present, Widespread | Native | |||||
Kenya | Present, Widespread | Native | |||||
Liberia | Present | Native | |||||
Madagascar | Present, Widespread | Native | |||||
Mayotte | Present | Native | |||||
Morocco | Present | Native | |||||
Mozambique | Present | Native | |||||
Rwanda | Present | Native | |||||
Senegal | Present | Native | |||||
Sierra Leone | Present | Native | |||||
South Africa | Present, Widespread | Native | Eastern Cape | ||||
Tanzania | Present, Widespread | Native | |||||
Togo | Present, Localized | Native | |||||
Uganda | Present, Widespread | Native | |||||
Zambia | Present | Native | |||||
Zimbabwe | Present | Native | |||||
Asia |
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China | Present | Present based on regional distribution. | |||||
-Yunnan | Present | Native | |||||
India | Present | Present based on regional distribution. | |||||
-Himachal Pradesh | Present, Few occurrences | Native | Growing in ditches in towns and farmland, Beas River. | ||||
-Uttarakhand | Present | Native | |||||
-West Bengal | Present | ||||||
Indonesia | Present, Widespread | Native | |||||
Japan | Present, Localized | Introduced | Invasive | Nara, Kochi, Wakayama, Kinki; First reported: 1950s | |||
Malaysia | Present | Native | |||||
Philippines | Present, Widespread | Native | |||||
Singapore | Present | Native | |||||
Thailand | Present | Native | |||||
Yemen | Present | Native | Also the type specimen for the species is from here. | ||||
Europe |
|||||||
Greece | Present | Present based on regional distribution. | |||||
-Crete | Present | ||||||
Italy | Present | Introduced | 2017 | ||||
Portugal | Present | Native | |||||
-Azores | Present | Introduced | 1844 | ||||
Spain | Present | Native | |||||
-Canary Islands | Present, Widespread | Native | |||||
North America |
|||||||
Antigua and Barbuda | Present | Introduced | |||||
Belize | Present, Widespread | Introduced | |||||
Costa Rica | Present, Widespread | Introduced | |||||
Cuba | Present | Introduced | Invasive | ||||
Dominica | Present, Widespread | Introduced | |||||
Dominican Republic | Present, Widespread | Introduced | |||||
El Salvador | Present, Widespread | Introduced | |||||
Guatemala | Present, Widespread | Introduced | |||||
Honduras | Present, Widespread | Introduced | |||||
Mexico | Present, Localized | Introduced | |||||
Nicaragua | Present, Widespread | Introduced | |||||
Panama | Present, Widespread | Introduced | |||||
Trinidad and Tobago | Present | Introduced | 1897 | ||||
United States | Present | Present based on regional distribution. | |||||
-Alabama | Present, Localized | Introduced | |||||
-Arkansas | Present, Localized | Introduced | |||||
-Florida | Present, Widespread | Introduced | |||||
-Georgia | Present, Localized | Introduced | |||||
-Hawaii | Present | Introduced | 1887 | ||||
-Kentucky | Present | Introduced | |||||
-Louisiana | Present, Localized | Introduced | |||||
-Mississippi | Present, Localized | Introduced | |||||
-South Carolina | Absent, Formerly present | Reported as a native species | |||||
-Texas | Present, Localized | Introduced | |||||
Oceania |
|||||||
American Samoa | Present | Native | |||||
Australia | Present, Widespread | Native | Including Lord Howe Island | ||||
-New South Wales | Present, Widespread | Native | |||||
-Northern Territory | Present, Localized | Native | |||||
-Queensland | Present, Widespread | Native | |||||
-South Australia | Present, Few occurrences | Native | |||||
-Victoria | Present, Few occurrences | Native | |||||
-Western Australia | Present, Few occurrences | Native | |||||
Fiji | Present | Native | |||||
French Polynesia | Present | Native | Recent studies say it is native | ||||
Guam | Present | Native | |||||
New Zealand | Present, Few occurrences | Native | Raoul Islands, Northern North Island, Geothermal sites in the Waikato | ||||
Norfolk Island | Present | Native | |||||
Papua New Guinea | Present | Native | |||||
Tonga | Present | Native | |||||
South America |
|||||||
Argentina | Present | Introduced | |||||
Bolivia | Present | Introduced | Chuquisaca, Cochabamba, La Paz, Santa Cruz | ||||
Brazil | Present | Present based on regional distribution. | |||||
-Goias | Present | Introduced | |||||
-Maranhao | Present | ||||||
-Mato Grosso do Sul | Present | Introduced | |||||
-Minas Gerais | Present | Introduced | |||||
-Parana | Present | Introduced | |||||
-Sao Paulo | Present | Introduced | |||||
Chile | Present | Native | |||||
Colombia | Present, Widespread | Native | |||||
Ecuador | Present, Widespread | Native | |||||
Paraguay | Present, Widespread | Native | |||||
Peru | Present, Localized | Native | |||||
Venezuela | Present, Widespread | Introduced |
History of Introduction and Spread
Top of pageC. dentata is native to the Old World tropics (widespread in Asia and Africa) and temperate parts of Australia and New Zealand (McCarthy, 1998), but is adventive in the Americas, where it was most likely introduced around 1900 as a greenhouse contaminant (Strother and Smith, 1970; Holttum, 1976; Smith, 1993). It has been described as having a tropical cosmopolitan distribution (Iwatsuki, 1963), but it also occurs in subtropical sites that are frost-free or nearly so, perhaps surviving a few frosts a year in northern Florida (GBIF, 2012). Specimens of this plant were not collected in the New World (e.g. Brazil, Florida) prior to the 1930s, and in some cases only after the 1940-1950s (e.g. Costa Rica and Hispaniola) (Strother and Smith, 1970).
C. dentata was first recorded in Japan in the 1950s and has since spread northward (possibly as a greenhouse contaminant) at a rate of 3 km per year, persisting through the winters probably as a result of urban heat islands (Murakami et al., 2007). In Hawaii the species was collected much earlier and was probably introduced in and established by the late 1800s (MacCaughey, 1918; Wagner, 1950).
It is not clear whether the two forms of C. dentata present in New Zealand (see Biology and Ecology) arrived within historic time or whether they have been established there rather longer, although the species was recorded early in the country's history, so it seems unlikely to have been introduced (P Brownsey, Museum of New Zealand, personal communication). There is similar uncertainty over C. dentata in Fiji.
C. dentata is regarded as native in Lord Howe Island, Norfolk Island, Tonga and Tahiti, although one publication suggests it is introduced in Tahiti (Iwatsuki 1963; Rodd and Pickard 1983; Murdock and Smith 2003; Orchard, 1994; Meyer et al., 2009).
Risk of Introduction
Top of pageC. dentata is an effective disperser that has reached some Pacific islands (e.g. New Zealand, Fiji, Raoul and Norfolk Islands) probably via natural means (Brownsey and Smith-Dodsworth, 1989; Wolf et al., 2001).
Its presence in Hawaii and the Americas is likely to be the result of accidental introduction (Strother and Smith 1970). The most probable human-mediated pathway for this plant’s introduction is accidentally via the horticultural trade. However, C. dentata is rarely traded as an ornamental plant now (Ko et al., 1997).
Habitat
Top of pageC. dentata is regarded as a facultative wetland plant. Both in its native and introduced ranges forested wetlands, damp woods and disturbed or open wet areas are typical habitats (Viane 1985; Flora of North America Editorial Committee 1993; USDA 2012). In Hawaiian forests it has colonized trails and road sides, weedy gulches and areas disturbed by pigs (C Buddenhagen, Florida State University, personal communication). In general it grows well in disturbed, wet sites. It often co-occurs with another widespread adventive fern, C. parasitica (=Cyclosorus parasiticus).
It is tolerant of a range of soil conditions, although it has been suggested as an indicator of calcareous conditions in South Carolina (Hill 1992) and has been found on limestone substrates in the Bahamas (Correll 1976). C. dentata can tolerate some shade.
Fronds of C. dentata are killed by exposure to -3 degrees Celsius for 2 hours or more (Given 1980). Frosts seem to limit the range of this species, although occasional frosts may be tolerated considering that it has been found growing in Kyoto (Japan) and South Carolina and Georgia (USA) (Norsworthy, 1966; Faircloth, 1975; Hill, 1992; Murakami et al., 2007; GBIF, 2012; USDA, 2012). In New Zealand C. dentata occurs in geothermal sites (Lange et al. 1999).
Habitat List
Top of pageCategory | Sub-Category | Habitat | Presence | Status |
---|---|---|---|---|
Terrestrial | Managed | Cultivated / agricultural land | Present, no further details | |
Terrestrial | Managed | Protected agriculture (e.g. glasshouse production) | Present, no further details | Harmful (pest or invasive) |
Terrestrial | Managed | Managed forests, plantations and orchards | Present, no further details | Natural |
Terrestrial | Managed | Disturbed areas | Principal habitat | |
Terrestrial | Managed | Urban / peri-urban areas | Principal habitat | Harmful (pest or invasive) |
Terrestrial | Natural / Semi-natural | Natural forests | Principal habitat | Harmful (pest or invasive) |
Terrestrial | Natural / Semi-natural | Wetlands | Principal habitat | Harmful (pest or invasive) |
Host Plants and Other Plants Affected
Top of pagePlant name | Family | Context | References |
---|---|---|---|
Ananas comosus (pineapple) | Bromeliaceae | Main | |
Hevea brasiliensis (rubber) | Euphorbiaceae | Unknown | |
Oryza sativa (rice) | Poaceae | Unknown |
Biology and Ecology
Top of pageGenetics
2 n = 144 (Flora of North America, 1993).
For other chromosome counts see Löve et al. (1977). There is also evidence of polyploidy in C. dentata.
Diversity
There are believed to be two forms in New Zealand: one is the true C. dentata, with a long-creeping rhizome and which occurs only in a couple of places in the northern North Island (and is also reasonably common on Raoul Island and Norfolk islands) (P Brownsey, Museum of New Zealand, personal communication). The other has an erect or short-creeping rhizome and occurs around thermal areas and also on Raoul Island (although occurs less commonly there than true C. dentata) (Brownsey and Smith-Dodsworth, 1989). The relationship between these two forms and whether they are both attributable to C. dentata remains to be determined.
Climate
Top of pageClimate | Status | Description | Remark |
---|---|---|---|
A - Tropical/Megathermal climate | Preferred | Average temp. of coolest month > 18°C, > 1500mm precipitation annually | |
Af - Tropical rainforest climate | Preferred | > 60mm precipitation per month | |
Am - Tropical monsoon climate | Preferred | Tropical monsoon climate ( < 60mm precipitation driest month but > (100 - [total annual precipitation(mm}/25])) | |
C - Temperate/Mesothermal climate | Tolerated | Average temp. of coldest month > 0°C and < 18°C, mean warmest month > 10°C | |
Cf - Warm temperate climate, wet all year | Tolerated | Warm average temp. > 10°C, Cold average temp. > 0°C, wet all year | |
Cw - Warm temperate climate with dry winter | Tolerated | Warm temperate climate with dry winter (Warm average temp. > 10°C, Cold average temp. > 0°C, dry winters) |
Latitude/Altitude Ranges
Top of pageLatitude North (°N) | Latitude South (°S) | Altitude Lower (m) | Altitude Upper (m) |
---|---|---|---|
35 | 38 |
Soil Tolerances
Top of pageSoil drainage
- free
- impeded
- seasonally waterlogged
Soil reaction
- alkaline
- neutral
Soil texture
- light
- medium
Means of Movement and Dispersal
Top of pageOccasional long-distance dispersal (100s of kilometers) from Australia or elsewhere has been suggested as an explanation for C. dentata occurrences in New Zealand and South Pacific islands (Given, 1980; McGlone et al., 2001).
Its presence in Hawaii and the Americas is probably the result of accidental introduction (Strother and Smith, 1970). The most likely human-mediated pathway for this plant’s introduction is accidentally via the horticultural trade.
Spores and gametophytes could easily be transported and are likely contaminants of nurseries, greenhouses, house plants and the potted plant trade, provided the climate is suitable.
Pathway Causes
Top of pageCause | Notes | Long Distance | Local | References |
---|---|---|---|---|
Disturbance | Colonizes disturbed gullies, trailsides and areas frequented by pigs. For references, please see te | Yes | ||
Escape from confinement or garden escape | This is not an example of an escape but the planting of it as an ornamental | Yes | Drummond (1959) | |
Flooding and other natural disasters | As a facultative wetland plant one could imagine its spread by this means. | Yes | USDA-NRCS (2012) | |
Garden waste disposal | Weed of urban areas | Yes | CSIRO (1998); Randall (2002); Randall (2009) | |
Hitchhiker | Spores and gametophytes could be easily transported | Yes | ||
Horticulture | Associated with greenhouse cultivation | Yes | Drummond (1959); Murakami et al. (2007); Strother and Smith (1970); Wagner (1950) | |
Ornamental purposes | Attractive ferns such as this could be spread intentionally in some cases. | Yes | Drummond (1959) |
Pathway Vectors
Top of pageVector | Notes | Long Distance | Local | References |
---|---|---|---|---|
Plants or parts of plants | Unknown speculated about in the literature. | Yes | Yes | Murakami et al. (2007); Strother and Smith (1970); Wagner (1950); Wagner (1972) |
Threatened Species
Top of pageThreatened Species | Conservation Status | Where Threatened | Mechanism | References | Notes |
---|---|---|---|---|---|
Poa mannii (Mann's bluegrass) | CR (IUCN red list: Critically endangered); USA ESA listing as endangered species | Hawaii | Competition | US Fish and Wildlife Service (2010b) | |
Pritchardia napaliensis | CR (IUCN red list: Critically endangered); USA ESA listing as endangered species | Hawaii | Competition | US Fish and Wildlife Service (2010a) | |
Remya montgomeryi (Kalalau Valley remya) | CR (IUCN red list: Critically endangered); USA ESA listing as endangered species | Hawaii | Competition | US Fish and Wildlife Service (2010d) | |
Schiedea apokremnos (Kauai schiedea) | CR (IUCN red list: Critically endangered); USA ESA listing as endangered species | Hawaii | Competition | US Fish and Wildlife Service (2010c) |
Risk and Impact Factors
Top of page- Invasive in its native range
- Proved invasive outside its native range
- Has a broad native range
- Abundant in its native range
- Highly adaptable to different environments
- Is a habitat generalist
- Pioneering in disturbed areas
- Tolerant of shade
- Highly mobile locally
- Long lived
- Has high reproductive potential
- Reproduces asexually
- Damaged ecosystem services
- Ecosystem change/ habitat alteration
- Modification of successional patterns
- Monoculture formation
- Reduced native biodiversity
- Threat to/ loss of endangered species
- Threat to/ loss of native species
- Competition - monopolizing resources
- Competition - shading
- Competition - smothering
- Hybridization
- Interaction with other invasive species
- Highly likely to be transported internationally accidentally
- Difficult to identify/detect as a commodity contaminant
- Difficult to identify/detect in the field
Detection and Inspection
Top of pageThis species is easily confused with C. parasitica (=Cyclosorus parasiticus)(Wagner 1950). Living plants of C. parasitica are paler, with a duller green, and its proximal pinnae are narrower. Most importantly, its fronds are not dimorphic and they do not have the sharp break between sterile and fertile fronds that C. dentata has. C. dentata’s sterile fronds are broader, shorter, more spreading than the others and generally entirely without sori.
Similarities to Other Species/Conditions
Top of pageThis species is easily confused with C. parasitica (=Cyclosorus parasiticus) (Wagner, 1950). Living plants of C. parasitica are paler and a duller green, and have narrower proximal pinnae. Most importantly, its fronds are not dimorphic and do not have the sharp break between sterile and fertile fronds that C. dentata has. C. dentata’s sterile fronds are broader, shorter, and more spreading than the others, and generally entirely without sori.
A key to Chinese species of the subgenus Cyclosoriopsis (including both Cyclosorus parasiticus and Christella dentata) is provided by Li et al. (2013).
Prevention and Control
Top of pageDue 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.
With long-distance dispersal (100s of kilometers) being possible via the dispersal of spores, as evidenced from its likely unassisted arrival to New Zealand and other South Pacific Islands, this is a species that may be difficult or impossible to contain once established in a region.
Hand weeding or treatment with herbicide have been used to control C. dentata. The application of triclopyr at standard foliar rates or at high concentrations with biodiesel to the rhizome has been shown to work (J Beachy, US Fish and Wildlife Service, personal communication).
Gaps in Knowledge/Research Needs
Top of pageMore could be done to understand the history of the spread of this species around the world, in both its introduced and its native range. The genetic connectivity between populations could tell us more about this species’ spread in short- and long-term evolutionary timeframes.
References
Top of pageBartsch I; Lawrence J, 1997. Leaf Size and Biomass Allocation in Thelypteris Dentata, Woodwardia Virginica and Osmunda Regalis in Central Florida. Leaf Size and Biomass Allocation in Thelypteris Dentata, Woodwardia Virginica and Osmunda Regalis. American Fern Journal:71-76.
Brownlie G, 1959. Some Problems in New Zealand Fern Nomenclature. Transactions of the Royal Society in New Zealand, 87:195-198.
Brownsey PJ; Jermy AC, 1973. A Fern Collection Expedition to Crete. The British Fern Gazette, 10(6):331-348.
Brownsey PJ; Perrie LR, 2011. A revised Checklist of Fijian ferns and lycophytes. Telopea, 13:513-562.
Correll D, 1976. Origin of the Pteridophyte Flora of the Bahamas, Caicos and Turks Islands. American Fern Journal, 66(2):46-48.
CSIRO, 1998. Ferns, gymnosperms and allied groups. Canberra, Australia: Australian Biological Resources Study/CSIRO.
Drummond WC, 1959. The Fern Dell, Los Angeles. American Fern Journal:2-9.
Evenhuis NL; Eldredge LG, 2011. Taxonomic Changes in Hawaiian Ferns and Lycophytes. Bishop Museum Occasional Papers, 110:11-16.
Faircloth WR, 1975. Ferns and Other Primitive Vascular Plants of Central South Georgia. Castanea 40(3):217-228.
Fish and Wildlife Service US, 2010. Lo`ulu (Pritchardia napaliensis) 5-Year Review. A Status Review to Determine If They Are Appropriately Listed Under the U. Endangered Species Act. Lo`ulu (Pritchardia napaliensis) 5-Year Review. Honolulu, Hawaii, USA: Department of Interior, Fish and Wildlife Service. http://ecos.fws.gov/docs/five_year_review/doc3317.pdf
Fish and Wildlife Service US, 2010. Schiedea apokremnos (maolioli) 5-Year Review. A Status Review to Determine If They Are Appropriately Listed Under the U. Endangered Species Act. Schiedea apokremnos (maolioli) 5-Year Review. Honolulu, Hawaii, USA: US Fish and Wildlife Service. http://ecos.fws.gov/docs/five_year_review/doc3319.pdf
Fish and Wildlife Service US2, 2010. Remya montgomeryi (5-Year Review). A Status Review to Determine if They Are Appropriately Listed Under the U. Endangered Species Act. Remya montgomeryi (5-Year Review). Honolulu, Hawaii, USA: US Fish and Wildlife Service. http://ecos.fws.gov/docs/five_year_review/doc3343.pdf
Fosberg FR; Sachet MH, 1981. Nomenclatural Notes on Micronesian Ferns. American Fern Journal 71(3):82-84.
GBIF, 2012. Global Biodiversity Information Facility. Global Biodiversity Information Facility (GBIF). http://data.gbif.org
Given D, 1980. Vegetation on Heated Soils at Karapiti, Central North Island, New Zealand, and Its Relation to Ground. Vegetation on Heated Soils at Karapiti, Central North Island, New Zealand. Nwe Zealand Journal of Botany 18(1):1-13.
Grayum MH; Churchill HW, 1987. An Introduction to the Pteridophyte Flora of Finca La Selva, Costa Rica. American Fern Journal 77(3):73-89.
He LJ; Zhang XC, 2012. Exploring Generic Delimitation Within the Fern Family Thelypteridaceae. Molecular Phylogenetics and Evolution 65(2):757-764.
Hill SR, 1992. Calciphiles and Calcareous Habitats of South Carolina. Castanea 57(1):25-33.
Holttum RE, 1976. The Genus Christella Leveille, Sect. The Genus Christella Leveille. Kew Bulletin 31(2), Sect:293-339. [Christella Studies in the Family Thelypteridaceae, XI.]
Iwatsuki K, 1963. New or Noteworthy Ferns from the Tonga Islands. American Fern Journal 53(4):133-138.
Joncheere GJ de, 1960. Ferns in Oubangi, Congo. American Fern Journal 50(3):228-231.
Leonard J, 1994. Periodically flooded vegetation of the sandstone cliffs of the Yanonge (Yangambi-Kisangani, Zaire) (La vegetation periodiquement inondee des falaises greseuses de Yanonge (Yangambi-Kisangani, Zaire)). Bulletin of the National Botanical Garden of Belgium 63(1):101-123.
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MacCaughey V, 1918. An Ecological Survey of the Hawaiian Pteridophytes. Journal of Ecology 6(3):199-219.
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Nair VD; Bissett NJ; Portier KM; Graetz DA; Segal DS; Garren RA, 2000. Soil conditions and plant establishment on reclaimed phosphate-mined uplands. Proceedings of the Seventeenth Annual Meeting of the American Society for Surface Mining and Reclamation: A New Era of Land Reclamation, 2000.
Norsworthy J, 1966. Fern Records for Echols County and the State of Georgia. American Fern Journal 56(2):55-57.
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Palmer DD, 2002. Taxonomic Notes on Hawaiian Pteridophytes. American Fern Journal 92(2):97-104.
Palmer DD, 2003. Hawaii's Ferns and Fern Allies. Honolulu, Hawaii, USA: University of Hawai'i Press.
Porter DM, 1987. Darwin notes on Beagle plants. Bulletin of the British Museum (Natural History):145-233.
Quansah N; Edwards DS, 1986. A Natural Bi-generic Fern Hybrid in Thelypteridaceae from Ghana. Kew Bulletin 41(4):805-809.
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Rhymer JM; Simberloff D, 1996. Extinction by Hybridization and Introgression. Annual Review of Ecology and Systematics: 83-109.
Robinson RC, 2009. Invasive and Problem Ferns: a European Perspective. International Urban Ecology Review:83.
Rodd AN; Pickard J, 1983. Census of Vascular Flora of Lord Howe Island. Cunninghamia 1(2):267-280.
Schelpe E, 1954. Ecological Observations on Pteridophyta in the Kangra Himalaya. American Fern Journal:49-65.
Silva MC da; Izidine S; Amude AB, 2004. A preliminary checklist of the vascular plants of Mozambique. Pretoria, South Africa: South African Botanical Diversity Network.
Smith AR, 1993. Phytogeographic Principles and Their Use in Understanding Fern Relationships. Journal of Biogeography:255-264.
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St John EP, 1936. Rare ferns of central Florida. American Fern Journal 26(2):41-50.
Stone BC, 1971. The flora of Guam: A manual for the identification of the vascular plants of the island, 6. University of Guam, Guam: Micronesica, 659p.
Strother JL; Smith AR, 1970. Chorology, Collection Dates, and Taxonomic Responsibility. Taxon 19(6):871-874.
Tagawa M; Iwatsuki K, 1965. On a Small Collection of Thailand Ferns. Southeast Asian Studies 3:70-89.
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Velazquez TS, 2005. Taxonomic key of the Pterifoflora of the Canary Islands (Clave taxonomica de la pteridoflora de las Islas Canarias). Botanica Complutensis, 28:39-50.
Viane RLL, 1985. A New Species and a New Hybrid of Thelypteris (Pteridophyta) from the Ivory Coast. Bulletin of the Royal Botanical Garden of Belgium:41-56.
Wagner WH, 1950. Ferns Naturalized in Hawaii. Occasional Papers of the Bishop Museum 20(8):95-120.
Wagner WH, 1972. Disjunctions in Homosporous Vascular Plants. Annals of the Missouri Botanical Garden 59(2):203-217.
Whistler WA, 1998. A study of the rare plants of American Samoa. Report prepared for the US Fish and Wildlife Service. A study of the rare plants of American Samoa, 1. Honolulu, USA: US Fish and Wildlife Service, 18.
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Distribution References
Bartsch I, Lawrence J, 1997. Leaf Size and Biomass Allocation in Thelypteris Dentata, Woodwardia Virginica and Osmunda Regalis in Central Florida. In: American Fern Journal, 71-76.
Brownsey PJ, Jermy AC, 1973. A Fern Collection Expedition to Crete. In: The British Fern Gazette, 10 (6) 331-348.
Brownsey PJ, Perrie LR, 2011. A revised Checklist of Fijian ferns and lycophytes. In: Telopea, 13 513-562.
CABI, Undated. Compendium record. Wallingford, UK: CABI
CABI, Undated a. CABI Compendium: Status inferred from regional distribution. Wallingford, UK: CABI
CABI, Undated b. CABI Compendium: Status as determined by CABI editor. Wallingford, UK: CABI
Faircloth WR, 1975. Ferns and Other Primitive Vascular Plants of Central South Georgia. In: Castanea, 40 (3) 217-228.
Fosberg FR, Sachet MH, 1981. Nomenclatural Notes on Micronesian Ferns. In: American Fern Journal, 71 (3) 82-84.
GBIF, 2012. Global Biodiversity Information Facility. http://www.gbif.org/species
Hill SR, 1992. Calciphiles and Calcareous Habitats of South Carolina. In: Castanea, 57 (1) 25-33.
Iwatsuki K, 1963. New or Noteworthy Ferns from the Tonga Islands. In: American Fern Journal, 53 (4) 133-138.
Joncheere GJ de, 1960. Ferns in Oubangi, Congo. In: American Fern Journal, 50 (3) 228-231.
Norsworthy J, 1966. Fern Records for Echols County and the State of Georgia. In: American Fern Journal, 56 (2) 55-57.
Porter DM, 1987. Darwin notes on Beagle plants. In: Bulletin of the British Museum (Natural History), 145-233.
Rodd AN, Pickard J, 1983. Census of Vascular Flora of Lord Howe Island. In: Cunninghamia, 1 (2) 267-280.
Schelpe E, 1954. Ecological Observations on Pteridophyta in the Kangra Himalaya. In: American Fern Journal, 49-65.
Silva MC da, Izidine S, Amude AB, 2004. A preliminary checklist of the vascular plants of Mozambique., Pretoria, South Africa: South African Botanical Diversity Network.
St John EP, 1936. Rare ferns of central Florida. In: American Fern Journal, 26 (2) 41-50.
Stone BC, 1971. The flora of Guam: A manual for the identification of the vascular plants of the island., 6 Guam: University of Guam, Micronesica. 659.
Tagawa M, Iwatsuki K, 1965. On a Small Collection of Thailand Ferns. In: Southeast Asian Studies, 3 70-89.
Velazquez TS, 2005. Taxonomic key of the Pterifoflora of the Canary Islands. (Clave taxonomica de la pteridoflora de las Islas Canarias). In: Botanica Complutensis, 28 39-50.
Whistler WA, 1998. A study of the rare plants of American Samoa. In: Report prepared for the US Fish and Wildlife Service. A study of the rare plants of American Samoa, 1 Honolulu, USA: US Fish and Wildlife Service. 18.
Organizations
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USA: US Fish and Wildlife Service, http://www.fws.gov/
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