Cyperus difformis
[Smallflower Umbrella Sedge]
Close-up views:
Below is the inflorescence (flower cluster) of a plant that grew from my pot in January 2015. The fruits, matured over a period of 2 months, were tiny nut-liked structure and greenish-yellow in colour with a length of about 0.5 millimetre. The dark brown objects among the fruits were likely to be the husks.