Elytraria imbricata R. Br., Acanthaceae

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Present on Pacific Islands?  yes

Primarily a threat at high elevations?  no

Other Latin names:  Elytraria tridentata Vahl; Justicia imbricata Vahl

Common name(s): [more details]

English: purple scalystem

Habit:  herb

Description:  "Acaulescent, or if caulescent the leaves crowded at tips of glabrous or sparingly pilosulous stems to 60 cm long; leaf blades ovate to oblong or obovate, rarely linear-lanceolate, 1-18 cm long, 0.5-6 cm wide, blunt or subacute at apex, narrowed at base to a slender winged petiole, both surfaces appressed-pilose or glabrate, margins undulate; scapes numerous, axillary, 1-24 cm long, simple or branched (sometimes leafy at tip), covered by tightly appressed ovate to subulate scales; spikes 1 to several, to 6 cm long; bracts oblong or elliptic; 3-6 mm long, 1-2 mm wide, firm, awn-tipped and bearing a pair of triangular or rhombic hyaline teeth near apex; bractlets 3 mm long; calyx segments thin, the upper bidentate; corolla blue to lavender-purple, 5-8 mm long; capsule oblong, glabrous"  (Wiggins & Porter, 1971; p. 264).

Habitat/ecology:  "Usually growing on bushy slopes, in thickets, and in shrubby forests at low elevations" (Wiggins & Porter, 1971; p. 264).

Propagation:  Seed

Native range:  Southern USA, Mexico, Central and 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
Ecuador (Galápagos Islands) Isabela Group	Isabela Island	introduced invasive	Charles Darwin Foundation (2008) Observed in survey, no herbarium record.
Ecuador (Galápagos Islands) Santa Cruz Group	Santa Cruz Island	introduced invasive	Charles Darwin Foundation (2008)
Philippines Philippine Islands	Philippine Islands	introduced invasive	Merrill, Elmer D. (1923) (p. 468) In open waste places, dry thickets, etc., in and about towns at low altitudes.

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) Arizona, Texas

Comments:  Probably not native to the Galápagos Islands, possibly introduced, per Charles Darwin Research Station.

Control:  If you know of control methods for Elytraria imbricata, please let us know.