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. (2011)
Philippines Philippine Islands	Philippine Islands	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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 (2011) "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. (2011)
China China	China (People's Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Indonesia Indonesia	Indonesia (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Japan Japan	Japan (country)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Malaysia Malaysia	Malaysia (country of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Singapore Singapore	Singapore (Republic of)	native	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 35)
Taiwan Taiwan	Taiwan Island	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Thailand Thailand	Thailand (Kingdom of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)
Vietnam Vietnam	Vietnam (Socialist Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2011)

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. (2011)

Additional information:
Additional online information about Diplazium esculentum is available from the Hawaiian Ecosystems at Risk project (HEAR).

Information about Diplazium esculentum as a weed (worldwide references) may be available from the Global Compendium of Weeds (GCW).

Taxonomic information about Diplazium esculentum may be available from the Germplasm Resources Information Network (GRIN).

References:

Australian Biological Resources Study. 2011. Flora of Australia Online. Australian Biological Resources Study, Canberra.

Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. 2009. A checklist of the total vascular plant flora of Singapore: native, naturalised and cultivated species. Raffles Museum of Biodiversity Research, National University of Singapore. 273 pp.

Oppenheimer, Hank. 2007. New plant records from Moloka‘i, Lāna‘i, Maui, and Hawai‘i for 2006. In: Evenhuis, Neal L. and Eldredge, Lucias G., eds. Records of the Hawaii Biological Survey for 2006. Part 2: Notes. Bishop Museum Occasional Papers 96:17-34.

Staples, George W./Herbst, Derral R. 2005. A tropical garden flora: plants cultivated in the Hawaiian Islands and other tropical places. Bishop Museum Press, Honolulu. 908 pp.

Staples, George W./Herbst, Derral/Imada, Clyde T. 2000. Survey of invasive or potentially invasive cultivated plants in Hawai‘i. Bishop Museum Occasional Papers No. 65. 35 pp.

U.S. Dept. Agr., Agr. Res. Serv. 2011. National Genetic Resources Program. Germplasm Resources Information Network (GRIN). Online searchable database.

U.S. Dept. Agr., Nat. Res. Cons. Serv. 2011. The PLANTS Database. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.