Lepidagathis, WILLD. FROM

Dhatchanamoorthy, Narayanasamy, Karthikeyan, Chinnasamy, Raja, Prakasam, Soosairaj, Sebastian & Balachandran, Natesan, 2022, Lepidagathis decumbens N. Dhatchan. & S. Soosairaj, sp. nov. (Acanthaceae), a new species from Tamil Nadu, India, Adansonia (3) 44 (24), pp. 321-329 : 328

KEY TO THE GENUS LEPIDAGATHIS WILLD. FROM TAMIL NADU

1. Prostrate-decumbent herb, capsule 2-seeded ................................................................................................ 2

— Erect subshrub, capsule 4-seeded ................................................................................................................. 8

2. Leaf margin or apex spinous tipped ............................................................................................................. 3 Leaf margin entire or toothed, apex mucronate ........................................................................................... 4

3. Leaves lanceolate, margin entire, one spine only at apex .......................................... L. spinosa Wight ex Nees

— Leaves ovate-oblong, margin and apex spinous tipped ....................................................... L. barberi Gamble

4. Spike aggregated only at lower nodes ........................................................................................................... 5

— Spike at axils of leafy and leafless stem ......................................................................................................... 7

5. Leaves> 3 cm long, lateral nerves 5-7 pairs .................................................................. L. hamiltoniana Wall.

— Leaves <3 cm long, lateral nerves 3-5 pairs ................................................................................................. 6

6. Leaves scabrous along the nerves beneath, margin ciliate ........................................................ L. mitis Dalzell

— Leaves glabrous on both sides, margin entire to toothed ....................................................... L. cristata Willd.

7. Spike globose-ovoid, internodes long to 3 cm ................................................................ L.diffusa C.B. Clarke

— Spike elongate and unilateral, internodes short to 1 cm ......... L. decumbens N. Dhatchan. & S. Soosairaj , sp. nov.

8. Bract and calyx lobes single nerved, bract margin hyaline ....................................................... L. hyalina Nees

— Bract and calyx lobes 3-7 nerved, bract scarious or coriaceous ..................................................................... 9

9. Bract scarious, lower calyx lobes 3-ribbed, upper 7-ribbed ...................................................... L. scariosa Nees

— Bract coriaceous, calyx lobes 3-ribbed ........................................................................................................ 10

10. Flowers in soft, condensed spike, leaves crenate-serrate ........................................... L. fasciculata (Retz.) Nees

— Flowers in elongate spike, villous, leaves entire or undulate ................................................. L. cuspidata Nees