Asystasia Blume, 1826

Kumar, Anant, Krishna, Gopal & Bhattacharjee, Avishek, 2023, Asystasia venui (Justicieae: Acanthaceae): A new species from West Bengal, India, Phytotaxa 600 (4), pp. 239-247 : 245

Key to the Indian species of Asystasia Blume

1. Corolla with long cylindrical tube and indistinct ventricose or expanded above..............................................................................2.

- Corolla with short tube and distinctly ventricose above ...................................................................................................................4.

2. Flowers in elongated lax terminal racemes; corolla bright mauve with violet tinge at corolla mouth ................. Asystasia neesiana

- Flowers in condensed racemes; corolla rose-pink, or white with light blue tinge at corolla mouth .................................................3.

3. Leaves gradually attenuate at base, long acuminate at apex; calyx lobes sublinear; corolla rose-pink, ca. 5 cm long; corolla lobes rose-pink, reflexed at maturity ............................................................................................................................ Asystasia atroviridis

- Leaves abruptly attenuate at base, short acuminate at apex; calyx lobes linear-lanceolate; corolla white, ca. 2.8 cm long; lobes white with one lobe light blue tinge at mouth, not reflexed at maturity .................................................................... Asystasia venui

4. Branches and leaves grey-puberulous ...............................................................................................................................................5.

- Branches and leaves glabrous or slightly pubescent .........................................................................................................................6.

5. Corolla 2–3 cm across, white, purple, cream to yellow; stamens included; ovary densely villose with non-glandular hairs ............. .............................................................................................................................................................................. Asystasia gangetica

- Corolla 1–1.5 cm across, white with purple-violet-spotted; stamens exserted; ovary densely covered with short glandular and simple hairs................................................................................................................................................................. Asystasia indica

6. Leaves entire at margins....................................................................................................................................................................7.

- Leaves crenulate or crispate at margins.................................................................................................................. Asystasia crispata

7. Leaves linear-lanceolate, lanceolate or elliptic-oblong .....................................................................................................................8.

- Leaves ovate or ovate-elliptic..........................................................................................................................................................12.

8. Inflorescences a lax, paired panicle........................................................................................................................... Asystasia pusilla

- Inflorescences terminal/subterminal solitary raceme or spike, rarely racemes up to 3, subpaniculate.............................................9.

9. Leaves linear-lanceolate or linear-elliptic, 10–20 × 1.5–3 cm; corolla 1–2 cm long ......................................................................10.

- Leaves lanceolate or elliptic to oblong, 2.5–12 × 1.2–4 cm; corolla 1.2–3.5 cm long....................................................................11.

10. Plant erect; racemes 1–3, subpaniculate; flowers distinctly pedicellate.......................................................... Asystasia travancorica

- Plant semi-scandent; raceme solitary; flowers sessile or subsessile .................................................................... Asystasia variabilis

11. Corolla 1.2–1.8 cm long, white .......................................................................................................................... Asystasia mysorensis

- Corolla 2.5–3.5 cm long, mauve ...................................................................................................................... Asystasia macrocarpa

12. Leaves ovate-elliptic, 1.5–3 × 1–2 cm; corolla purple or pinkish (or rarely white as in var. alba only) ........... Asystasia dalzelliana

- Leaves ovate to broadly ovate-elliptic, 5–18 × 2.5–4.5 cm; corolla white to pale purple ............................... Asystasia chelonoides