Gomphostemma niveum Hook.f., Fl. Brit. India 4: 697 1885.;
Assam to Bangladesh as per POWO;

MS,Oct,2021/03 Undershrub for id: 3 images.
Location: Hmunpui
Date : 23-07-2015
Habit : Undershrub
Habitat : Wild

Please check Acanthaceae !

May I request you to post high res. images to check the details as per the following:
Two species found in India are very close as per keys in Flora of China:

8 (7) Bracts 1- or 3-veined; calyx teeth linear to triangular-lanceolate Gomphostemma parviflorum
+ Bracts inconspicuously 1- or 3-veined; calyx teeth linear Gomphostemma crinitum
Do you have the keys?

3 high res. images.

I think it should be Gomphostemma niveum as per GBIF specimens- one and two.
Looks different from images at Gomphostemma parviflorum




References: POWO  Catalogue of Life  The Plant List Ver.1.1  WCSP  IPNI  GBIF specimens- one and two (High resolution specimens) India Biodiversity Portal