Murdannia esculenta (Wall. ex C.B.Clarke) Abeyw., Ceylon J. Sci., Biol. Sci. 2: 82 (1959) (syn: Aneilema esculentum Wall. ex C.B.Clarke; Aneilema pulneyense Fyson; Aneilema pulneyense Fyson; Commelina esculenta B.Heyne ex Hook.f., not validly publ.; Phaeneilema pulneyense (Fyson) Raizada);
India, Sri Lanka as per WCSP;

Leaves oblong-elliptic, to 6.5 x 0.8 cm, plicate, recurved, base obtuse, apex acute; sheath 1.5 cm. Panicles to 5 cm; peduncle to 6 cm; bracts 1.5 mm; pedicel 5 mm. Perianth 3+3; outer lobes oblong, 5 mm; inner ones obovate, 6 mm, pink to violet. Stamens 3; filaments 3.5 mm; staminodes 2.5 mm. Ovary 2 mm; style 2.5 mm. Capsule 8.5 mm; seeds 1-seriate, a few per cell, 1.5 mm, tuberculate.
Flowering and fruiting: August-December
Paddy fields
(Attributions- Dr. N Sasidharan (Dr. B P Pal Fellow), Kerala Forest Research Institute, Peechi from India Biodiversity Portal)

Kodaikanal flora 020914 TBN 3 for id:: SEP TBN 3 : 6 posts by 3 authors. Attachments (2).
Please identify this plant details of which are as follows:
Date :16.08.14                                                            
Location :Mannavanur
Altitude :6500 ft
Habitat :wild grassland
Habit :herb
Height :less than a feet

Is it a trimerous flower? If so, is it a monocot?

Yes, a monocot, likely to be a Murdannia sp. ..Commelinaceae

Need more views to determine its proper ID, … is correct it is Murdannia species.

Thanks … Hope to take better photos next time. Did not want to uproot the plant.

Perhaps, Murdannia esculenta

I guess correct ID but image information is not sufficient.