Oxalis Triangularis Purpurea also known as the Purple Shamrock.  Pretty pale lilac flowers above purple black leaves...the leaves start off a reddish colour, darkening to dark purple depending on amount of light.  Leaves close up at night!

Can be grown as a beautiful houseplant or planted outside in borders, rockeries, baskets and containers.

Grow in best light possible to achieve the darkest leaf colour.

Plants grown as house plants tend to be slightly taller than outdoors, and plants have a dormant period once a year, usually in the winter, but start to grow again quite soon.