Isoglossa laxiflora, Lindau, 1911

Champluvier, Dominique & Fischer, Eberhard, 2020, Isoglossa darbyshirei (Acanthaceae), a new plietesial species from the Albertine Rift (Rwanda, Burundi), Phytotaxa 438 (5), pp. 276-288 : 284-285

Key to the species of the Isoglossa laxiflora -group

1 Corolla cream with purple spots, tube 11.0– 13.5 mm long and 6–11 mm in diameter at mouth, upper lip 9 × 6 mm, lower lip 9 × 8 mm; leaves oblong, 5 (–13) × 2.0–2.5(–4) cm, long acuminate at apex; montane forest and bamboo in Eastern D.R. Congo, Rwanda............................................................................................................................................................................... I. laxiflora

1’ Corolla wine-red; leaves narrowly elliptic-obovate to broadly ovate ................................................................................................2

2 Corolla (23–) 28–32 mm long, tube(14–) 18–20 mm long and 4.0– 7.5 mm in diameter at mouth, upper lip 9.5–12.0 mm long, lower lip 9.0– 13.5 mm long; leaves narrowly elliptic to obovate, 8.0(–14.5) × 2.0–3.0(–6.5) cm; upper montane forest and bamboo, 2250–2750 m, Eastern D.R. Congo, Uganda.................................................................................................................... I. humbertii

2’ Corolla 40–43 mm long, tube 25–28 mm long and 10 mm in diameter at mouth, upper lip 14 x 10 mm, lower lip 15 x 10 mm; leaves broadly ovate, up to 14.0–14.5 × 6.5–8.0 cm, with short acuminate apex; dense montane forest, 1900–2000 m, Rwanda, Burundi.......................................................................................................................................................................... I. darbyshirei