Key to Codonopsis gongshanica and its allies

1. Corolla campanulate, 1.7–5.5 cm long; reticulate veins present on corolla surfaces ........................................................................2

– Corolla tubular, 0.9–2 cm long; veins absent on corolla surfaces......................................................................................................5

2. Vines; corolla campanulate, 3.3–5.5 cm long, ca. 3 cm wide; calyx lobe linear-lanceolate. ................................ Codonopsis farreri

– Herbs erect or scandent; corolla broadly campanulate, 1.7–4 cm long and 1–4 cm wide; calyx lobes ovate or ovate-triangular.....3

3. Leaf blade deltoid-ovate or broadly ovate......................................................................................................... Codonopsis deltoidea

– Leaf blade non-deltoid........................................................................................................................................................................4

4. Stem branched; leaves non-rosulate, 1.5–3.5(–5) cm long, 1.3–3 cm wide; leaf base slightly cordate or rounded. .......................... ......................................................................................................................................................................... Codonopsis viridiflora

– Stem simple; leaves sub-rosulate, 3–11 cm long, 1.5–3.8 cm wide; leaf base cuneate.................................... Codonopsis meleagris

5. Stems erect, mostly simple; leaves sub-rosulate; leaf base cuneate, margins entire to slightly sinuate; corolla grey or slightly pale purple, lobed to ca. 1/6, with a pale amaranthine ring below throat. .......................................................... Codonopsis gongshanica

– Stems procumbent, ascending or trailing, always branched at lower and middle parts; leaves non-rosulate; leaf base cordate, or rounded, margins crenate, dentate, or recurved; corolla pale yellow, yellow-green or pale blue, lobed to 1/4 or 1/3, without rings. ............................................................................................................................................................................................................6

6. Leaf base cordate, margins recurved; corolla lobed to ca. 1/3 ........................................................................ Codonopsis bhutanica

– Leaf base rounded or cuneate, margins crenate or dentate; corolla lobed to ca. 1/4 ..................................... Codonopsis subsimplex