Justicia gendarussa Burm. f., Acanthaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Gendarussa vulgaris Nees

Common name(s): [more details]

Chinese: qin qiu, xiao bo gu

English: black malabar nut, water willow, willow-leaved justicia

French: ayapana marron, laliapana marron, natchouli, nitchoulli, yapana malgache, yapana marron

Tagalog: kapanitulot

Thai: chiang phraa mon

Habit:  herb

Description:  "Subshrubs 0.7-1.5 cm tall, much branched. Stems subterete, swollen at nodes, glabrous. Petiole 3-10 mm; leaf blade narrowly lanceolate, 6-10 x 1-1.5 cm, glabrous, secondary veins 5-8 on each side of midvein, base cuneate to attenuate, margin subsinuate, apex acute to shortly acuminate. Spikes terminal or axillary, 3-12 cm, interrupted, usually in a leafy panicle; peduncle 0.5-1.5 cm; bracts triangular, 2-6 x 1-2.5 mm, basal ones longer than calyx then gradually smaller with apicalmost ones shorter than calyx, margin ciliate, apex acute; bracteoles elliptic to linear-lanceolate, ca. 3 x 1 mm, margin ciliate, apex acute. Calyx ca. 5 mm, 5-lobed; lobes linear-lanceolate, 3-4 x ca. 0.5 mm, subequal, apex acuminate. Corolla creamy white, 1.2-1.5 cm; tube basally cylindric and ca. 2 mm wide for 8-9 mm; lower lip violet dotted basally, cuneate-obovate, 6-10 mm broad, 3-lobed, lobes oblanceolate and 3-5 x ca. 3.5 mm; upper lip violet blotched, triangular, ca. 7 x 3.5 mm, 2-cleft. Stamens exserted; filaments 3-6 mm, glabrous; anther thecae oblong, ca. 1.2 mm, superposed, lower one spurred at base, upper one muticous. Ovary glabrous; style ca. 1 cm, glabrous; stigma capitate, shortly 2-lobed. Capsule clavate, ca. 1.2 cm"  (Flora of China online).

Habitat/ecology:  "Locally naturalized in Mauritius and La Réunion in moist forest understorey or near rivers up to 850 m elevation.  The species is widely naturalized in the forest understoreys of Rodrigues where it is considered as invasive.  It is also sparingly naturalized in the Seychelles, especially in montane rain forests along rivers at about 720 m elevation"  (Meyer & Lavergne; 2004; p. 338).

Propagation:  Seed (rarely).  "The plant is rarely found in fruit in the Mascarenes"  (Meyer & Lavergne; 2004; pp. 338, 345).

Native range:  China and possibly other southeast Asia countries; exact native range obscure; naturalized elsewhere (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	O‘ahu Island		Bishop Museum (U.S.A. Hawaii. Honolulu.) (2000) (voucher ID: BISH 664557) Taxon name on voucher: Justicia gendarussa Burm.f.
Papua New Guinea Papua New Guinea (eastern New Guinea Island)	Papua New Guinea (eastern New Guinea Island)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
Philippines Philippine Islands	Philippine Islands	uncertain if 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
Cambodia Cambodia	Cambodia (Kingdom of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013)
China China	China (People's Republic of)	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Roadsides, thickets. Naturalized or cultivated in Guangdong, Guangxi, Hainan, Yunnan.
Indonesia Indonesia	Indonesia (Republic of)	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Java; possibly native to the Moluccas Naturalized
Malaysia Malaysia	Malaysia (country of)	uncertain if native	U.S. Dept. Agr., Agr. Res. Serv. (2013) Malaya
Singapore Singapore	Singapore (Republic of)	introduced cultivated	Chong, Kwek Yan/Tan, Hugh T. W./Corlett, Richard T. (2009) (p. 52)
Taiwan Taiwan Island	Taiwan Island	native	Zhengyi, Wu/Raven, Peter H./Deyuan, Hong (2013) Roadsides, thickets.
Thailand Thailand	Thailand (Kingdom of)	uncertain if native	U.S. Dept. Agr., Agr. Res. Serv. (2013)
Vietnam Vietnam	Vietnam (Socialist Republic of)	uncertain if 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
Australia (Indian Ocean offshore islands) Christmas Island Group	Christmas Island	introduced cultivated	Swarbrick, J. T. (1997) (p. 117) Garden remnant.
Australia (Indian Ocean offshore islands) Christmas Island Group	Christmas Island	introduced invasive	Australian Biological Resources Study (2013) Probably introduced in cultivation by the Chinese, now naturalised at South Point. Vouchers cited: D.A. Powell 536 (K), D.A. Powell 793 (K).
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
La Réunion (France) La Réunion Island	La Réunion Island	introduced invasive	Meyer, Jean-Yves/Lavergne, Christophe (2004) (p. 338)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Mauritius Island	introduced invasive	Meyer, Jean-Yves/Lavergne, Christophe (2004) (p. 338)
Mauritius Mautitius Islands (Mauritius and Rodrigues)	Rodrigues Island	introduced invasive	Meyer, Jean-Yves/Lavergne, Christophe (2004) (p. 338)
Seychelles Seychelles Islands	Seychelles Islands	introduced invasive	U.S. Dept. Agr., Agr. Res. Serv. (2013) Naturalized
Seychelles Seychelles Islands	Seychelles Islands	introduced	Invasive Species Specialist Group (2017)

Control:  If you know of control methods for Justicia gendarussa, please let us know.