Casuarina glauca Sieber ex Spreng., Casuarinaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Risk assessment results:  High risk, score: 20 (Go to the risk assessment)

Common name(s): [more details]

Chinese: cu zhi mu ma huang

English: gray sheoak, grey bull-oak, long-leaf ironwood, longleaf ironwood, marsh she-oak, saltmarsh ironwood, scaly-bark beefwood, suckering Australian pine, swamp oak, swamp she-oak

French: filao multipliant

Habit:  tree

Description:  "Trees usually 15-18 m tall; branches long, coarse, usually glaucous.  Leaf sheaths with 9-18 teeth.  Staminate spikes densely flowered, ca. 2.5 cm long, bracts pubescent, especially at base.  Cones subglobose, flat-topped, ca. 0.7-1.3 cm in diameter, the valves prominent, protruding ca. 1-1.5 mm, pubescent, apex obtuse.  Nuts ca. 4.7-5 mm long (including wing)" (Wagner et al., 1999; p. 529).

"Trees dioecious, to 20 m tall. Trunk to 35 cm d.b.h.; bark grayish brown or grayish black, finely fissured and scaly, pale yellow adaxially. Ultimate branchlets ascending to pendulous, grayish green or glaucous green, rather long, to 1 m, 0.9-1.4 mm in diameter; articles 1-1.8 cm, slightly swollen at apex. Leaves erect but those of new shoots strongly recurved, 12-17 per whorl, narrowly lanceolate. Male inflorescences 1-3 cm. Cones broadly ellipsoid to subglobose, 1.2-2 cm, truncate at both ends; apex of bracteoles broadly acute to obtuse. Samaras 4-6 mm including wing"  (Flora of China online).

Habitat/ecology:  This species is very similar to Casuarina equisetifolia. However, it forms suckers prolifically, producing dense stands. It is the most aggressive ironwood in Hawai‘i (Smith, 1985; p. 187).  "Coastal beaches, sandy banks.  In the native range, this tree occurs on saline swamp flats, on estuarine floodplains, wetland forests and along salt marshes.  The tree is nitrogen-fixing and not as salt tolerant as [Casuarina equisetifolia].  The tree produces large amounts of litter that prevent the growth and establishment of native species"  (Weber, 2003; p. 89).

Propagation:  Wind-borne seed; suckers profusely.

Native range:  New South Wales and Queensland, Australia; 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
American Samoa Tutuila Islands	Tutuila Island	introduced cultivated	Space, James C./Flynn, Tim (2000) (p. 33)
Australia (Pacific offshore islands) Lord Howe Island	Lord Howe Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 19) "A native of Australia (eastern N.S.W. and Qld) which has been introduced on the Islands and, with its tendency to sucker, has become naturalised". Vouchers cited: I. Hutton 592 (K), I. Hutton 593 (K)
Australia (Pacific offshore islands) Norfolk Islands	Norfolk Island	introduced invasive	Orchard, Anthony E., ed. (1994) (p. 8) "A native of Australia (eastern N.S.W. and Qld) which has been introduced on the Islands and, with its tendency to sucker, has become naturalised. The plants on Norfolk Is. are reported to be male only". Voucher cited: G. Uhe 1229 (K)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 529)
State of Hawaii Hawaiian Islands	Hawai‘i (Big) Island	introduced invasive	Oppenheimer, Hank L./Bartlett, R. T. (2000) (p. 3) Voucher cited: P.M. Burch L107 (BISH 579940) Spreading by root sprouts.
State of Hawaii Hawaiian Islands	Kaho‘olawe Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 529)
State of Hawaii Hawaiian Islands	Kaho‘olawe Island	introduced invasive cultivated	Starr, Forest/Starr, Kim (2011) (pp. 24-25) Voucher cited: Starr, Starr & Higashino 080208-02 (BISH)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 529)
State of Hawaii Hawaiian Islands	Kaua‘i Island	introduced invasive cultivated	Oppenheimer, Hank (2011) (p. 7) Voucher cited: Oppenheimer H110818 (BISH, PTBG)
State of Hawaii Hawaiian Islands	Lāna‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 529)
State of Hawaii Hawaiian Islands	Maui Island	introduced cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 529)
State of Hawaii Hawaiian Islands	Maui Island	introduced invasive	Oppenheimer, Hank L./Bartlett, R. T. (2000) (p. 3) West Maui. Vouchers cited: W.L. Wagner, C. Imada & W. Takeuchi 5856 (BISH 529839), Oppenheimer H99906 (BISH) Spreading vegetatively.
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 529)
State of Hawaii Hawaiian Islands	Moloka‘i Island	introduced invasive	Oppenheimer, Hank (2008) (p. 26) Voucher cited: Oppenheimer H110608 (BISH, PTBG)
State of Hawaii Hawaiian Islands	O‘ahu Island	introduced invasive cultivated	Wagner, Warren L./Herbst, Derral R./Sohmer, S. H. (1999) (p. 529)
Kiribati Phoenix Islands	Kanton Island	introduced cultivated	Fosberg, F. R./Stoddart, D. R. (1994) (pp. 16-17) Vouchers cited: Degener 21372, Fosberg 30876 (US), Clapp P-71-11 (US), Fosberg & Stoddart 54777 (US, HAW, K)
Kiribati Phoenix Islands	Kanton Island	introduced	Luomala, Katharine (1951) (p. 172) Voucher cited: Luomala 37
United States (other Pacific offshore islands) Midway Atoll	Midway Atoll	introduced invasive cultivated	Starr, Forest/Martz, Kim/Loope, Lloyd L. (2002) (p. 19) Voucher cited: Starr & Martz 990511-1 (BISH)
United States (other Pacific offshore islands) Midway Atoll	Sand Island	introduced invasive	Starr, Forest/Starr, Kim/Loope, Lloyd (2008) (pp. B-5)

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)	New South Wales	native	Australian Biological Resources Study (2013)
Australia Australia (continental)	Queensland	native	Australian Biological Resources Study (2013)
China China	China (People's Republic of)	introduced cultivated	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
New Zealand New Zealand	New Zealand (country)	introduced invasive	Webb, C. J./Sykes, W. R./Garnock-Jones, P. J. (1988) (p. 512) "Shingle pits and sandy banks, cemeteries". Known from only 3 collections.

Indian Ocean
Country/Terr./St. & Island group	Location	Cited status & Cited as invasive & Cited as cultivated & Cited as aboriginal introduction?	Reference & Comments
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Lavergne, Christophe (2006) "Naturalisé/±envahissant"
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Kueffer, C./Lavergne, C. (2004) (p. 5)
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Baret, Stephane/Rouget, Mathieu/Richardson, David M./Lavergne, Christophe/Egoh, Benis/Dupont, Joel/Strasberg, Dominique (2006) (p. 758)

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)

Comments:  A non-native Casuarina that is a pest in Hawai‘i.

Planting of this species in the State of Florida (U.S.) is prohibited by Florida Department of Environmental Protection (Hunsberger, 2001).

Control:  See control methods for Casuarina equisetifolia.