Blechnum appendiculatum Willd., Blechnaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 17 (Go to the risk assessment).

Habit:  fern

Description:  "May be recognized by its 1-pinnate fronds with pinnae having two long sori close to and parallel with the midribs, and stolon-bearing rhizomes.

"Plants medium-sized.  Rhizomes erect, stoloniferous, stolons subterranean, long-creeping.  Fronds 20-60 cm long, clustered at tips of rhizomes, young fronds colored pink to rosy.  Stipes about 1/2 frond length, straw-colored, with scattered tan scales in lower parts, well clothed with very short, chainlike hairs.  Blades 1-pinnate, lanceolate to ovate-lanceolate, pinnae well separated in basal 2/3, gradually becoming pinnatifid at tips; rachises grooved, straw-colored, abaxial surfaces well covered with very small, inconspicuous, 0.1-mm glands, small, short glandular hairs and stubby round-tipped hairs, abaxial surface with fewer of these structures.  Pinnae 6-20 pairs before becoming pinnatifid near blade tips, short-stalked proximally to adnate distally, ovate-lanceolate, 2.5-8 cm long, basal pinnae smaller or not, margins entire, adaxial costal groove not continuous with rachis groove.  Veins joining to form continuous linear veins (commissures) close to and parallel to costae, forking distally.  Sori long-linear on pericostal vein commissures, 1-5.5 cm long, extending most of length of pinnae.  Indusia tan, scarious, opening inward"  (Palmer, 2003; pp. 79-81).

Note:  This fern has uniformly been called Blechnum occidentale L. since it was first reported in Hawaii; however, the rachises of B. occidentale are entirely glabrous but those of B. appendiculatum Willd. are minutely pubescent and glandular, as is the naturalized Hawaiian species (Palmer, 2003; p. 81).

Habitat/ecology:  In Hawai‘i, "Common as clones forming large colonies in closed-canopy mesic forests, especially on rock or rocky substrates, and occurring in all but the most extreme habitats 30-1,560 m"  (Palmer, 2003; pp. 79-81).  "Prefers a half shady to shady site. It grows best in soils that are moist"  (Hortipedia).

Propagation:  Spores

Native range:  United States (Florida and Texas), Trinidad and Tobago, through Central America, South America (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 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)

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)	El Salvador (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Guatemala (Republic of)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Central America Central America (Pacific rim)	Honduras (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)
Central America Central America (Pacific rim)	Panama (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)
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)

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)	United States (other states)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013) Texas
United States (continental except west coast) United States (other states)	USA (Florida)	native	U.S. Dept. Agr., Agr. Res. Serv. (2013)

Control: 

Chemical: "Probably susceptible to dicamba and glyphosate"  (Motooka et al., 2003).