Identificaciones de zngow

A serious weed in a community garden--spreading more vigorously than kikuyu. I don't recognise it. It has small tuber-like nodules at the roots and spreads aggressively through underground rhizomes. Has emerged through a quarter metre of cardboard and mulch.

A shiny-leaved plant that spreads vigorously through rhizomes. It has not flowered in the 2 years I've lived here, but has increased in area by 10x. Any ideas? I will be digging it up and burning it to prevent spread as it's come up through my compost.