Key for Justicia L.

1Inflorescence slender, with few to numerous axillary and terminal spikes, bracts and bracteoles small, less than 2 x 1 mm (except in J. potarensis and J. prevostiae, whose bracts and bracteoles are 3.5-8 x 0.5-1.5 mm); corollas usually less than 15 mm long
1'Inflorescence dense, stout; bracts and bracteoles usually conspicuous, more than 2 x 1 mm; corollas usually more than 15 mm long (except in J. cayennensis, J. coppenamensis, J. oldemanii, J. polystachia, and J. wilhelminensis)
2Corolla 3-7 mm long; inflorescence axillary and terminal with 3-7 branches in whorls
2'Corolla 7.5-15 mm long; inflorescence mostly terminal, simple or with alternate branches
3Flowers secund in spikes of 3.5-7 cm long
3'Flowers in rather loose panicles of 7.5-17 cm long
4Plant rooting at lower nodes; leaf blades linear or narrowly lanceolate, 1-2.3 cm wide; capsule 14-17 mm long; seeds suborbicular, 5 x 5.5 mm, gray or flecked brown; in swampy regions
4'Plant rooting at base; leaf blades elliptic to broadly lanceolate to narrowly ovate to oblong, more than 2 cm wide; capsule 7-8.5 mm long; seeds lenticular, 2-2.3 x 1.75-2 mm, brownish, not flecked; in submontane forests, white sand river banks and terra firma at edge of streams
5Bract brownish when dry, narrowly linear to spathulate, 5-8 x 0.6-1.5 mm, glandular hirtellous; leaf blade elliptic to oblong, 10-13 x 3.5 cm; calyx subequally 5-lobed, lobes narrowly triangular, 4.5-5 x 0.3 mm, hirtellous
5'Bract green, narrowly lanceolate, 3.5-4 x 0.75 mm, glabrate to sparingly puberulous; leaf blade elliptic to broadly lanceolate to narrowly ovate, 4-7 x 2-2.7cm; calyx unequally 5-lobed, 4 lobes narrowly lanceolate, 4 x 0.5-0.75 mm, fifth lobe reduced, filiform, 2.5-3 mm long.
6Leaf blade ovate, decurrent on petiole from a rounded base; panicles 17 x15 cm; corolla completely yellow or with faint rose on lower lip, 9-10 mm long
6'Leaf blade ovate to lanceolate, acute at base, not decurrent on petiole; panicles 5-16 x 6 cm; corollas white, lilac, or purplish, 7.5-10 cm long
7Inflorescence compound, composed of spicate units that are usually secund and arranged along one main axis
7'Inflorescence a simple spike (sometimes terminal and axillary forming a cluster of spikes or a thyrse) with 2 flowers per node, a 2-3-flowered cyme, or reduced to 1 or 2 sessile, axillary flowers
8Erect herb, 0.8-1 m tall; corolla 50-60 mm long, brick red; calyx lobes linear, 15-17 x 1mm, tapering into a long, slender point
8'Herb or scandent shrub, 0.5-3 m tall; corolla 30-38(-40) mm long, pale red to dull crimson; calyx lobes oblong-lanceolate, 5-7 x 0.8-1.25 mm
9Bracts imbricate, conspicuously white with green venation, ovate-lanceolate, 10-15 x 8 mm; cultivated
9'Bracts otherwise, not white with green venation, obovate to suborbicular or spathulate or ovate (if ovate then green), membranous, asymmetrical, 6.5-10 x 7.5 mm, not cultivated
10Inflorescence a dense cluster of spikes forming a capitulum
10'Inflorescence otherwise, short spikes, cymes or clusters of spikes or thyrse
11Calyx 4-lobed; spikes 1.5-2.5 cm long
11'Calyx 5-lobed; spikes or thyrse 2-15 cm long
12Corollas 9-14 mm long, white to pinkish, pale lavender or light purple with dark lines or violet marked with lighter streaks on lower lip
12'Corollas 14.5-45 mm long, color otherwise, not marked with darker lines or with streaks on lower lip
13Floral bracts conspicuous, subopposite, membranous, obovate to ovate to suborbicular, 5-9 mm wide
13'Floral bracts not conspicuous decussate, firm, lanceolate to narrowly ovate to spathulate, 1.5-2.5 mm wide
14Weak herb, 60-150 cm tall; leaf blade oblong-lanceolate to broadly lanceolate, 7-13 x 1-3 cm; bract green; asymmetrically ovate, acute to obtuse apically, glabrous
14'Herb a creeping herb, 10-30 cm tall; leaf blade elliptic to narrowly ovate, 10-15 x 2.8-5.6 cm; bract heteromorphic, larger bract apically purplish, obovate to suborbicular, apiculate at apex, conspicously pubsecent
15Bract green, lanceolate to narrowly ovate, 4-5 x 1.5-2 mm, glabrous or minutely puberulous; calyx unequally 5-lobed, 4 lobes linear, 5th (posterior) lobe reduced; corolla violet, marked with lighter streaks on lower lips, 10-12 mm long
15'Bract reddish-brown when dry, spathulate, 9-11 x 2-2.25 mm, densely hirtellous with both eglandular and glandular trichomes; calyx subequally 5-lobed, lobes narrowly triangular, corolla pale lavender, soon falling, 9-10 mm long
16Bracts and bracteoles similar, narrowly triangular, 2-3 mm long, carinate, apically mucronulate, firm
16'Bracts and bracteoles otherwise, linear lanceolate, narrowly lanceolate to obovate to spathulate to suborbicular, 5-20 mm long, not carinate and apically not mucronulate
17Calyx distinctly white margined; corollas red, pink, pink-salmon, light pinkish-red or violet to reddish to purple, rarely white, (14-)17-45 mm long
17'Calyx not white margined; corolla white, violet, lavender or purple, 14.5-22.5 mm long
18Bracts conspicuous, elliptic to obovate to spathulate, 2.5-6.5 mm wide; corolla (14-)17-35 mm long, pubescent, tube (6-)8-18 mm long
18'Bracts inconspicuous, not readily distinguished from bracteoles and calyx lobes, linear lanceolate or narrowly lanceolate, 0.75-1.5 mm wide; corolla 30-45 mm long, glabrous or veins sparingly and minutely hirtellous, tube 20 mm long
19Inflorescence spike-like thryse, moderately dense, terminal, 2.5-6.5 cm long; peduncle 1.8-8.8 cm long; bract linear-lanceolate, 5-7.4 mm long; corolla violet, lavender or purple, 14.5 mm long
19'Inflorescence a spike, usually in pairs, terminal, 8-15 cm long; peduncle 7-16 cm long; bract heteromorphic, larger bract obovate to suboribicular, 8-9 mm long; corolla white, 22-22.5 mm long