Diplazium esculentum (Retz.) Sw., Woodsiaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 8 (Go to the risk assessment).

Common name(s): [more details]

English: edible fern, vegetable fern

Hawaiian: hō‘i‘o

Japanese: kuware-shida

Habit:  fern

Description:  "Rhizome erect, often forming a slender leaning black trunk to 1 m tall, scaly at the apex. Scales c. 1 cm long, dark brown; margins finely toothed; apex long-acuminate. Fronds 1-2 m long, 0.5-1 m wide, erect to arcuate. Stipe black and scaly at the base, paler above. Lamina 2-3-pinnate, 0.5-1.5 m long, 0.5-1 m wide, dark green. Secondary pinnae variable in size, commonly 5-8 cm long, 1.5-2.5 cm wide; margins very shallowly lobed; lobes toothed; basal lobes longer than the rest, glabrous beneath; veins simple or forked; lowest 3-5 pairs of adjacent vein groups anastomosing. Sori spreading along most veins; indusium thin, dark brown; margins becoming uneven with age"  (Flora of Australia online).

"Stems erect; scales brown, linear-lanceolate, margins dentate. Petiole 30-60 cm. Blade ovate, 2-pinnate to 2-pinnate-pinnatifid, 50-100 x 15-50 cm, base ± narrowed, apex abruptly acuminate. Pinnae 1-pinnate to 1-pinnate-pinnatifid. Pinnules oblong, base ± truncate, ± auriculate, apex acuminate, incised or lobed halfway to costule. Veins pinnate, anastomosing. Sori elongate, single or double, indusiate; indusia vaulted, thin, erose"  (Flora of North America online).

Habitat/ecology:  In Hawai‘i, "grows abundantly in wet valleys and can even thrive in sheltered spots with adequate moisture on the dry leeward sides of the Islands.  It is a frequent volunteer in gardens, making it difficult to ascertain how often it is cultivated deliberately"  (Staples & Herbs, 2005; p. 29).

Propagation:  "Easily propagated by spores.  Older plants bear runners that produce plantlets"  (Staples & Herbs, 2005; p. 29).  "Forms clonal colonies by vegetative increase from root buds"  (Flora of Australia online).

Native range:  Eastern and southeastern Asia to the Philippines; also cultivated (GRIN).

Presence:

Pacific
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced	Oppenheimer, Hank (2007) (p. 21)
State of Hawaii Hawaiian Islands	Hawaiian Islands	introduced invasive cultivated	Staples, George W./Herbst, Derral R. (2005) (p. 21)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced	Oppenheimer, Hank (2007) (p. 21)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced	Oppenheimer, Hank (2007) (p. 21)
State of Hawaii Hawaiian Islands	Maui Island	introduced	Oppenheimer, Hank (2007) (p. 21)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced	Oppenheimer, Hank (2007) (p. 21) Voucher cited: Oppenheimer H80503 (BISH)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced	Oppenheimer, Hank (2007) (p. 21)
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Pacific Rim
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
Australia Australia (continental)	Queensland	introduced invasive cultivated	Australian Biological Resources Study (2013) "Naturalised in a couple of swampy areas of south-eastern Queensland. Widely cultivated as an ornamental and for culinary purposes".
Cambodia Cambodia	Cambodia (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Japan Japan	Japan	native	U.S. Dept. Agr., Agr. Res. Serv. (2013) Kyushu
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Singapore Singapore	Singapore (Republic of)	native	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 35)
Taiwan Taiwan Island	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Also reported from
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
United States (continental except west coast) United States (other states)	USA (Florida)	introduced	U.S. Dept. Agr., Nat. Res. Cons. Serv. (2013)

Control:  If you know of control methods for Diplazium esculentum, please let us know.