Adiantum raddianum C.Presl, Pteridaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 15 (Go to the risk assessment).

Other Latin names:  Adiantum cuneatum Langsd. & Fischer

Common name(s): [more details]

English: delta maidenhair fern

Habit:  fern

Description:  "Rhizome short-creeping, branched, clothed with dark brown, lance-attenuate, entire scales to 0.8 mm long. Fronds close, erect-arching, glabrous, mostly 15-45 cm long, stipes dark reddish-brown to blackish, naked, equalling or exceeding the blades. Blades deltate or lance-ovate to broadly ovate, to 30 cm broad (usually less), 3- to 4-pinnate; pinnae and pinnules stalked; ultimate divisions cuneate-flabellate, symmetrical or not, not articulate, the sterile margins with each vein ending in a small notch or sinus. Sori solitary or few on each ultimate pinnule; indusoid flap pale or whitish, more or less orbicular-reniform." (Howard, 1977; pp. 189-190).

"Rather small terrestrial fern. Stipes dark, polished, persistently hairy, about equaling upper foliar part, blades pedate, lowest pinnules flabellate, upper ones obliquely rhomboidal, white-pubescent, outer margin dentate, sori small, marginal." (Plants of Tonga, pp. 35-36)

Habitat/ecology:  In the Lesser Antilles, "roadside banks and paths at middle elevations, naturalized" (Howard, 1977; pp. 189-190). In Hawai‘i, "it grows on moist and shaded rocks, slopes, and river and roadside banks" (Wilson, 1996).

Propagation:  Spores

Native range:  South America. "This species has escaped from cultivation at many localities in the American tropics, so that its true natural range is difficult to ascertain" (Howard, 1977; pp. 189-190).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
French Polynesia Gambier Islands	Mangareva (Gambier) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Naturalisée
French Polynesia Marquesas Islands	Nuku Hiva (Nukahiva) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Naturalisée
French Polynesia Society Islands	Bora Bora Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Voucher cited: J. Florence 12085 (PAP) Naturalisée
French Polynesia Society Islands	Maupiti (Maurua) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Voucher cited: J.-F. Butaud & F.A. Jacq 73 (PAP) Naturalisée
French Polynesia Society Islands	Moorea Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Vouchers cited: J. Florence 2232 (PAP), J. Florence 4797 (PAP), F.A. Jacq, J.-F. Butaud, F. Laure & V. Gaidou FJ 277 (PAP) Naturalisée
French Polynesia Society Islands	Tahiti Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Vouchers cited: P. Birnbaum 6 (PAP), M. Chaine 9 (PAP), J. Florence 2909 (PAP), J. Florence 3151 (PAP), J. Florence 3212 (PAP), J. Florence 7646 (PAP), J. Florence 8664 (PAP), J. Florence 8745 (PAP) Naturalisée
French Polynesia Society Islands	Tahiti Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1982) (voucher ID: PTBG 2786) Taxon name on voucher: Adiantum raddianum
French Polynesia Society Islands	Tahiti Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1981) (voucher ID: PTBG 2794) Taxon name on voucher: Adiantum raddianum
French Polynesia Society Islands	Tahiti Island		National Tropical Botanical Garden (U.S.A. Hawaii. Kalaheo.) (1982) (voucher ID: PTBG 2795) Taxon name on voucher: Adiantum raddianum
French Polynesia Tuamotu Archipelago	Makatea (Ma‘atea) Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Naturalisée
French Polynesia Austral (Tubuai) Islands	Rurutu Island	introduced invasive	Florence, J./Chevillotte, H./Ollier, C./Meyer, J.-Y. (2013) Naturalisée
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Wagner, W. L./Herbst, D. R./Lorence, D. H. (2013)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive	Wagner, W. L./Herbst, D. R./Lorence, D. H. (2013)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive	Wagner, W. L./Herbst, D. R./Lorence, D. H. (2013)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Wagner, W. L./Herbst, D. R./Lorence, D. H. (2013)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Wagner, W. L./Herbst, D. R./Lorence, D. H. (2013)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive	Wagner, W. L./Herbst, D. R./Lorence, D. H. (2013)
Kiribati Kiribati	Kiribati (Republic of)	introduced cultivated	Thaman, R. R. (1987) (p. 40)
Kiribati Tungaru (Gilbert) Islands	Tarawa Atoll	introduced	Fosberg, F. R./Sachet, M.-H. (1987) (p. 2)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Central America Central America (Pacific rim)	Costa Rica (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Nicaragua (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Mexico Mexico	Mexico (United Mexican States)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore Singapore	Singapore (Republic of)	introduced cultivated	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 10) Cultivated only
South America (Pacific rim) South America (Pacific rim)	Colombia	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Ecuador (Republic of) (continental)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
South America (Pacific rim) South America (Pacific rim)	Perú (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Mascarene Islands Mascarene Islands (Mauritius, La Reunion, Rodrigues)	Mascarene Islands	introduced	Lorence, David (year unknown)

Comments:  Reported to be invasive in the Mascarene Islands (David Lorence, pers. com.) and in Africa (Rejmánek, 1996).

Control:  If you know of control methods for Adiantum raddianum, please let us know.