Invasive Species Compendium

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Datasheet

Christella dentata
(soft fern)

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Datasheet

Christella dentata (soft fern)

Summary

  • Last modified
  • 27 September 2018
  • Datasheet Type(s)
  • Invasive Species
  • Preferred Scientific Name
  • Christella dentata
  • Preferred Common Name
  • soft fern
  • Taxonomic Tree
  • Domain: Eukaryota
  •   Kingdom: Plantae
  •     Phylum: Pteridophyta
  •       Class: Filicopsida
  •         Family: Thelypteridaceae
  • Summary of Invasiveness
  • C. 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 establis...

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Pictures

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PictureTitleCaptionCopyright
Christella dentata (soft fern, downy wood fern); habit and habitat. Honokowai Ditch Trail, Maui. June 21, 2010.
TitleHabit and habitat
CaptionChristella dentata (soft fern, downy wood fern); habit and habitat. Honokowai Ditch Trail, Maui. June 21, 2010.
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (soft fern, downy wood fern); habit and habitat. Honokowai Ditch Trail, Maui. June 21, 2010.
Habit and habitatChristella dentata (soft fern, downy wood fern); habit and habitat. Honokowai Ditch Trail, Maui. June 21, 2010.©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (soft fern, downy wood fern); habit on bridge - many plants growing, in a line, below bridge parapet. Puaa Kaa Park, Hana Hwy, Maui. July 02, 2009
TitleHabit on bridge
CaptionChristella dentata (soft fern, downy wood fern); habit on bridge - many plants growing, in a line, below bridge parapet. Puaa Kaa Park, Hana Hwy, Maui. July 02, 2009
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (soft fern, downy wood fern); habit on bridge - many plants growing, in a line, below bridge parapet. Puaa Kaa Park, Hana Hwy, Maui. July 02, 2009
Habit on bridgeChristella dentata (soft fern, downy wood fern); habit on bridge - many plants growing, in a line, below bridge parapet. Puaa Kaa Park, Hana Hwy, Maui. July 02, 2009©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (soft fern, downy wood fern); habit. Waihee Ridge Trail, Maui.  September 25, 2002
TitleHabit
CaptionChristella dentata (soft fern, downy wood fern); habit. Waihee Ridge Trail, Maui. September 25, 2002
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (soft fern, downy wood fern); habit. Waihee Ridge Trail, Maui.  September 25, 2002
HabitChristella dentata (soft fern, downy wood fern); habit. Waihee Ridge Trail, Maui. September 25, 2002©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (dsoft fern, owny wood fern); fronds and habit. Garden of Eden Keanae, Maui.  March 30, 2011
TitleFronds and habit
CaptionChristella dentata (dsoft fern, owny wood fern); fronds and habit. Garden of Eden Keanae, Maui. March 30, 2011
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (dsoft fern, owny wood fern); fronds and habit. Garden of Eden Keanae, Maui.  March 30, 2011
Fronds and habitChristella dentata (dsoft fern, owny wood fern); fronds and habit. Garden of Eden Keanae, Maui. March 30, 2011©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (soft fern, downy wood fern); sori. Sacred Garden of Maliko, Maui.  January 24, 2011
TitleSori
CaptionChristella dentata (soft fern, downy wood fern); sori. Sacred Garden of Maliko, Maui. January 24, 2011
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (soft fern, downy wood fern); sori. Sacred Garden of Maliko, Maui.  January 24, 2011
SoriChristella dentata (soft fern, downy wood fern); sori. Sacred Garden of Maliko, Maui. January 24, 2011©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (soft fern, downy wood fern); sori. Sacred Garden of Maliko, Maui.  January 24, 2011
TitleClose-up of sori
CaptionChristella dentata (soft fern, downy wood fern); sori. Sacred Garden of Maliko, Maui. January 24, 2011
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Christella dentata (soft fern, downy wood fern); sori. Sacred Garden of Maliko, Maui.  January 24, 2011
Close-up of soriChristella dentata (soft fern, downy wood fern); sori. Sacred Garden of Maliko, Maui. January 24, 2011©Forest Starr & Kim Starr - CC BY 4.0
Cyclosorus x intermedia (hybrid christella); habit. Makawao Forest Reserve, Maui.  April 05, 2003
TitleHybrid habit
CaptionCyclosorus x intermedia (hybrid christella); habit. Makawao Forest Reserve, Maui. April 05, 2003
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Cyclosorus x intermedia (hybrid christella); habit. Makawao Forest Reserve, Maui.  April 05, 2003
Hybrid habitCyclosorus x intermedia (hybrid christella); habit. Makawao Forest Reserve, Maui. April 05, 2003©Forest Starr & Kim Starr - CC BY 4.0
Cyclosorus x intermedia (hybrid christella); pinnules and sori. Makawao Forest Reserve, Maui.  April 05, 2003
TitlePinnules and sori
CaptionCyclosorus x intermedia (hybrid christella); pinnules and sori. Makawao Forest Reserve, Maui. April 05, 2003
Copyright©Forest Starr & Kim Starr - CC BY 4.0
Cyclosorus x intermedia (hybrid christella); pinnules and sori. Makawao Forest Reserve, Maui.  April 05, 2003
Pinnules and soriCyclosorus x intermedia (hybrid christella); pinnules and sori. Makawao Forest Reserve, Maui. April 05, 2003©Forest Starr & Kim Starr - CC BY 4.0

Identity

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Preferred 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

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C. 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

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  • Domain: Eukaryota
  •     Kingdom: Plantae
  •         Phylum: Pteridophyta
  •             Class: Filicopsida
  •                 Family: Thelypteridaceae
  •                     Genus: Christella
  •                         Species: Christella dentata

Notes on Taxonomy and Nomenclature

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Christella 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

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Stems 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).

Plant Type

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Perennial

Distribution

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C. 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 2003Orchard, 1994; Meyer et al., 2009). It has also been recorded from New Caledonia, Vanuatu, Samoa and the Cook Islands.

Distribution Table

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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.

Continent/Country/RegionDistributionLast ReportedOriginFirst ReportedInvasiveReferenceNotes

Asia

ChinaPresentPresent based on regional distribution.
-YunnanPresentNative Not invasive GBIF, 2012
IndiaPresentPresent based on regional distribution.
-Himachal PradeshPresent, few occurrencesNative Not invasive Schelpe, 1954Growing in ditches in towns and farmland, Beas River.
-UttarakhandPresentNative Not invasive GBIF, 2012
IndonesiaWidespreadNative Not invasive GBIF, 2012
JapanLocalisedIntroduced1950s Invasive Murakami et al., 2007; GBIF, 2012Nara, Kochi, Wakayama, Kinki
MalaysiaPresentNative Not invasive GBIF, 2012
PhilippinesWidespreadNative Not invasive GBIF, 2012
SingaporePresentNative Not invasive GBIF, 2012
ThailandPresentNative Not invasive Tagawa and Iwatsuki, 1965; GBIF, 2012
YemenPresentNative Not invasive GBIF, 2012Also the type specimen for the species is from here.

Africa

AngolaPresentNative Not invasive GBIF, 2012
BeninPresentNative Not invasive GBIF, 2012Atacora
Burkina FasoPresentNative Not invasive GBIF, 2012
BurundiWidespreadNative Not invasive GBIF, 2012Bubanza Bururi
CameroonPresentNative Not invasive GBIF, 2012
Cape VerdePresentNative Not invasive Porter, 1987
Central African RepublicPresentNative Not invasive GBIF, 2012
ComorosPresentNative Not invasive GBIF, 2012
CongoPresentNative Not invasive Joncheere, 1960; GBIF, 2012
Congo Democratic RepublicPresentNative Not invasive Leonard, 1994; GBIF, 2012
Côte d'IvoireWidespreadNative Not invasive GBIF, 2012
Equatorial GuineaPresentNative Not invasive GBIF, 2012
EthiopiaPresentNative Not invasive GBIF, 2012
GabonWidespreadNative Not invasive GBIF, 2012
GhanaWidespreadNative Not invasive GBIF, 2012
KenyaWidespreadNative Not invasive GBIF, 2012
LiberiaPresentNative Not invasive GBIF, 2012
MadagascarWidespreadNative Not invasive GBIF, 2012
MayottePresentNative Not invasive GBIF, 2012
MoroccoPresentNative Not invasive GBIF, 2012
MozambiquePresentNative Not invasive Silva et al., 2004
RwandaPresentNative Not invasive GBIF, 2012
SenegalPresentNative Not invasive GBIF, 2012
Sierra LeonePresentNative Not invasive GBIF, 2012
South AfricaWidespreadNative Not invasive GBIF, 2012Eastern Cape
Spain
-Canary IslandsWidespreadNative Not invasive Velazquez, 2005; GBIF, 2012
SwazilandLocalisedNative Not invasive GBIF, 2012
TanzaniaWidespreadNative Not invasive GBIF, 2012
TogoLocalisedNative Not invasive GBIF, 2012
UgandaWidespreadNative Not invasive GBIF, 2012
ZambiaPresentNative Not invasive GBIF, 2012
ZimbabwePresentNative Not invasive GBIF, 2012

North America

MexicoLocalisedIntroducedGBIF, 2012
USAPresentPresent based on regional distribution.
-AlabamaLocalisedIntroducedGBIF, 2012
-ArkansasLocalisedIntroducedGBIF, 2012
-FloridaWidespreadIntroducedSt John, 1936; Bartsch and Lawrence, 1997; GBIF, 2012
-GeorgiaLocalisedIntroducedNorsworthy, 1966; Faircloth, 1975; GBIF, 2012
-KentuckyPresentIntroducedGBIF, 2012
-LouisianaLocalisedIntroducedGBIF, 2012
-MississippiLocalisedIntroducedGBIF, 2012
-South CarolinaAbsent, formerly presentIntroducedHill, 1992Reported as a native species
-TexasLocalisedIntroducedGBIF, 2012

Central America and Caribbean

Antigua and BarbudaPresentIntroducedGBIF, 2012
BelizeWidespreadIntroducedGBIF, 2012
Costa RicaWidespreadIntroducedGBIF, 2012
CubaPresentIntroduced Invasive GBIF, 2012; Oviedo Prieto et al., 2012
DominicaWidespreadIntroducedGBIF, 2012
Dominican RepublicWidespreadIntroducedGBIF, 2012
El SalvadorWidespreadIntroducedGBIF, 2012
GuatemalaWidespreadIntroducedGBIF, 2012
HondurasWidespreadIntroducedGBIF, 2012
NicaraguaWidespreadIntroducedGBIF, 2012
PanamaWidespreadIntroducedGBIF, 2012

South America

ArgentinaPresentIntroducedGBIF, 2012
BoliviaPresentIntroducedGBIF, 2012Chuquisaca, Cochabamba, La Paz, Santa Cruz
BrazilPresentPresent based on regional distribution.
-GoiasPresentIntroducedGBIF, 2012
-Mato Grosso do SulPresentIntroducedGBIF, 2012
-Minas GeraisPresentIntroducedGBIF, 2012
-ParanaPresentIntroducedGBIF, 2012
-Sao PauloPresentIntroducedGBIF, 2012
ChilePresentNativeGBIF, 2012
ColombiaWidespreadNativeGBIF, 2012
EcuadorWidespreadNativeGBIF, 2012
ParaguayWidespreadNativeGBIF, 2012
PeruLocalisedNativeGBIF, 2012
VenezuelaWidespreadIntroducedGBIF, 2012

Europe

GreecePresentPresent based on regional distribution.
-CretePresentBrownsey and Jermy, 1973
PortugalPresentNative Not invasive GBIF, 2012
SpainPresentNative Not invasive GBIF, 2012

Oceania

American SamoaPresentNative Not invasive Whistler, 1998
AustraliaWidespreadNative Not invasive P Brownsey, Museum of New Zealand, personal communication; Rodd and Pickard, 1983Including Lord Howe Island
-Australian Northern TerritoryLocalisedNative Not invasive GBIF, 2012
-New South WalesWidespreadNative Not invasive GBIF, 2012
-QueenslandWidespreadNative Not invasive GBIF, 2012
-South AustraliaPresent, few occurrencesNative Not invasive GBIF, 2012
-VictoriaPresent, few occurrencesNative Not invasive GBIF, 2012
-Western AustraliaPresent, few occurrencesNative Not invasive GBIF, 2012
FijiPresentNativeBrownsey and Perrie, 2011
French PolynesiaPresentNative Not invasive Murdock and Smith, 2003Recent studies say it is native
GuamPresentNative Not invasive Stone, 1971; Fosberg and Sachet, 1981
New ZealandPresent, few occurrencesNative Not invasive P Brownsey, Museum of New Zealand, personal communication; Brownsey and Smith-Dodsworth, 1989; Lange et al., 1999; GBIF, 2012Raoul Islands, Northern North Island, Geothermal sites in the Waikato
Norfolk IslandPresentNative Not invasive GBIF, 2012
Papua New GuineaPresentNative Not invasive GBIF, 2012
TongaPresentNative Not invasive Iwatsuki, 1963

History of Introduction and Spread

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C. 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 2003Orchard, 1994; Meyer et al., 2009).

Risk of Introduction

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C. 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

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C. 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

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CategorySub-CategoryHabitatPresenceStatus
Terrestrial
Terrestrial – ManagedCultivated / agricultural land Present, no further details
Protected agriculture (e.g. glasshouse production) Present, no further details Harmful (pest or invasive)
Managed forests, plantations and orchards Present, no further details Natural
Disturbed areas Principal habitat
Urban / peri-urban areas Principal habitat Harmful (pest or invasive)
Terrestrial ‑ Natural / Semi-naturalNatural forests Principal habitat Harmful (pest or invasive)
Wetlands Principal habitat Harmful (pest or invasive)

Host Plants and Other Plants Affected

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Plant nameFamilyContext
Ananas comosus (pineapple)BromeliaceaeMain

Biology and Ecology

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Genetics

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

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ClimateStatusDescriptionRemark
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

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Latitude North (°N)Latitude South (°S)Altitude Lower (m)Altitude Upper (m)
35 38

Air Temperature

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Parameter Lower limit Upper limit
Mean annual temperature (ºC) 0

Soil Tolerances

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Soil drainage

  • free
  • impeded
  • seasonally waterlogged

Soil reaction

  • alkaline
  • neutral

Soil texture

  • light
  • medium

Means of Movement and Dispersal

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Occasional 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

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CauseNotesLong DistanceLocalReferences
DisturbanceColonizes disturbed gullies, trailsides and areas frequented by pigs. For references, please see te Yes
Escape from confinement or garden escapeThis is not an example of an escape but the planting of it as an ornamental Yes Drummond, 1959
Flooding and other natural disastersAs a facultative wetland plant one could imagine its spread by this means. Yes USDA-NRCS, 2012
Garden waste disposalWeed of urban areas Yes CSIRO, 1998; Randall, 2002; Randall, 2009
HitchhikerSpores and gametophytes could be easily transported Yes
HorticultureAssociated with greenhouse cultivation Yes Drummond, 1959; Murakami et al., 2007; Strother and Smith, 1970; Wagner, 1950
Ornamental purposesAttractive ferns such as this could be spread intentionally in some cases. Yes Drummond, 1959

Pathway Vectors

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VectorNotesLong DistanceLocalReferences
Plants or parts of plantsUnknown speculated about in the literature. Yes Yes Murakami et al., 2007; Strother and Smith, 1970; Wagner, 1950; Wagner, 1972

Impact Summary

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CategoryImpact
Environment (generally) Negative

Threatened Species

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Threatened SpeciesConservation StatusWhere ThreatenedMechanismReferencesNotes
Poa mannii (Mann's bluegrass)CR (IUCN red list: Critically endangered) CR (IUCN red list: Critically endangered); USA ESA listing as endangered species USA ESA listing as endangered speciesHawaiiCompetitionUS Fish and Wildlife Service, 2010b
Pritchardia napaliensisCR (IUCN red list: Critically endangered) CR (IUCN red list: Critically endangered); USA ESA listing as endangered species USA ESA listing as endangered speciesHawaiiCompetitionUS Fish and Wildlife Service, 2010a
Remya montgomeryi (Kalalau Valley remya)CR (IUCN red list: Critically endangered) CR (IUCN red list: Critically endangered); USA ESA listing as endangered species USA ESA listing as endangered speciesHawaiiCompetitionUS Fish and Wildlife Service, 2010d
Schiedea apokremnos (Kauai schiedea)CR (IUCN red list: Critically endangered) CR (IUCN red list: Critically endangered); USA ESA listing as endangered species USA ESA listing as endangered speciesHawaiiCompetitionUS Fish and Wildlife Service, 2010c

Risk and Impact Factors

Top of page Invasiveness
  • 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
Impact outcomes
  • 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
Impact mechanisms
  • Competition - monopolizing resources
  • Competition - shading
  • Competition - smothering
  • Hybridization
  • Interaction with other invasive species
Likelihood of entry/control
  • Highly likely to be transported internationally accidentally
  • Difficult to identify/detect as a commodity contaminant
  • Difficult to identify/detect in the field

Uses List

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General

  • Botanical garden/zoo

Detection and Inspection

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This 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

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This 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

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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

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More 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

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Bartsch 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.

Brownsey PJ; Smith-Dodsworth JC, 1989. New Zealand ferns and allied plants. Auckland, New Zealand: David Bateman Ltd., viii + 168 pp.

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.

Durand LZ; Goldstein G, 2001. Growth, leaf characteristics, and spore production in native and invasive tree ferns in Hawaii. American Fern Journal, 91(1):25-35.

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.

Ko MP; Schmitt DP; Saxby M, 1997. Effects of container bases on the spread of Meloidogyne incognita in a Hawaiian ornamental nursery. Plant Disease, 81(6):607-613.

Kraus F; Duffy DC, 2010. A successful model from Hawaii for rapid response to invasive species. Journal for Nature Conservation, 18(2):135-141.

Lange PJ de; Heenan PB; Given DR; Norton DA; Ogle CC; Johnson PN; Cameron EK, 1999. Threatened and uncommon plants of New Zealand. New Zealand Journal of Botany, 37(4):603-628.

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.

Li ZY; He ZR; Zhang XC, 2013. A taxonomic revision of Cyclosorus subgenus Cyclosoriopsis (Thelypteridaceae) from China. Journal of Systematics and Evolution, 51(5):609-638. http://dx.doi.org/10.1111/jse.12013

Love A; Love D; Pichi Sermolli REG, 1977. Cytotaxonomical atlas of the Pteridophyta. J Cramer Publishing, 398 pp.

MacCaughey V, 1918. An Ecological Survey of the Hawaiian Pteridophytes. Journal of Ecology 6(3):199-219.

Mascaro J; Becklund KK; Hughes RF; Schnitzer SA, 2008. Limited native plant regeneration in novel, exotic-dominated forests on Hawai'i. Forest Ecology and Management, 256(4):593-606. http://www.sciencedirect.com/science/journal/03781127

McCarthy PM, 1998. Flora of Australia. Volume 48: Ferns, gymnosperms and allied groups. Flora of Australia. Volume 48: Ferns, gymnosperms and allied groups. Melbourne, Australia: ABRS/CSIRO Australia, xxi + 766 pp.

McGlone MS; Duncan RP; Heenan PB, 2001. Endemism, species selection and the origin and distribution of the vascular plant flora of New Zealand. Journal of Biogeography [Historical biogeography and patterns of diversity. XVI International Botanical Congress, St Louis, USA, August 1999.], 28(2):199-216.

Meyer JY; Fourdrigniez M; Taputuarai R, 2009. Evaluation of terrestrial biodiversity of the island of Me'eti'a (Society archipelago) (Evaluation de la biodiversite terrestre de l'ile de Me'eti'a (archipel de la Societe). Contribution a la Biodiversite de Polynesie francaise N18. Sites Naturels d'Interet Ecologique et Patrimonial VII). Paris, France: Ministry of Education, Higher Education, Research and Culture.

Murakami K; Matsui R; Morimoto Y, 2007. Northward invasion and range expansion of the invasive fern Thelypteris dentata (Forssk.) St. John into the urban matrix of three prefectures in Kinki District, Japan. American Fern Journal, 97(4):186-198. http://www.bioone.org/bioone/?request=get-archive&issn=0002-8444

Murdock AG; Smith AR, 2003. Pteridophytes of Moorea, French Polynesia, with a new species, Tmesipteris gracilis (Psilotaceae). Pacific Science, 57(3):253-265.

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.

North America Flora of North America Editorial Committee, 1993. Flora of North America north of Mexico. Volume 2: Pteridophytes and Gymnosperms. New York, USA: Oxford University Press, xvi + 475 pp.

Orchard AE, 1994. Flora of Australia. Vol. 49, Oceanic islands 1. Canberra, Australia: Australian Government Publishing Service.

Oviedo Prieto R; Herrera Oliver P; Caluff MG, et al. , 2012. National list of invasive and potentially invasive plants in the Republic of Cuba - 2011. (Lista nacional de especies de plantas invasoras y potencialmente invasoras en la República de Cuba - 2011). Bissea: Boletín sobre Conservación de Plantas del Jardín Botánico Nacional de Cuba, 6(Special Issue 1):22-96.

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.

Randall RP, 2002. A Global Compendium of Weeds. Melbourne, Australia: RG & FJ Richardson.

Randall RP, 2009. The introduced flora of Australia and its weed status. CRC for Australian Weed Management. Glen Osmond, Australia: University of Adelaide. http://www.weedscrc.org.au/documents/intro_flora_australia.pdf

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.

Smith AR; Pryer KM; Schuettpelz E; Korall P; Schneider H; Wolf PG, 2006. A Classification for Extant Ferns. Taxon 55(3):705-731.

Smith CW, 1985. Impact of alien plants on Hawaii's native biota. In: Hawaii's terrestrial ecosystems: preservation and management. Proceedings of a symposium held June 5-6, 1984, at Hawaii Volcanoes National Park. [ed. by Stone CP, Scott JM] Honolulu, HI, USA: University of Hawaii Press, 180-250.

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.

The Plant List, 2013. The Plant List: a working list of all plant species. Version 1.1. London, UK: Royal Botanic Gardens, Kew. http://www.theplantlist.org

US Fish and Wildlife Service, 2010. 5-Year review. Short Form Summary Species Reviewed: Poa mannii (Mann's bluegrass). 5-Year review. Short Form Summary Species Reviewed: Poa mannii (Mann's bluegrass). 10 pp. http://ecos.fws.gov/docs/five_year_review/doc3296.pdf

USDA-NRCS, 2012. The PLANTS Database. Baton Rouge, USA: National Plant Data Center. http://plants.usda.gov/

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.

Wolf PG; Schneider H; Ranker TA, 2001. Geographic Distributions of Homosporous Ferns: Does Dispersal Obscure Evidence of Vicariance? Geographic Distributions of Homosporous Ferns. Journal of Biogeography, 28(2):263-270.

Organizations

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USA: University of Hawaii UH, Manoa, Honolulu, http://www.hawaii.edu

USA: US Fish and Wildlife Service, http://www.fws.gov/

Contributors

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14/11/12 Original text by:

Buddenhagen CE, Florida State University, USA

Distribution Maps

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