Gday Dug,
I can probably clarify that term for you a bit. Imagine that the gumleaf in your photo is the surrounding rock and the vein that runs down the centre is quartz, now see all the small veins that run off it - these are like stringers. Small veins of quartz that have spread into cracks from the main source of the quartz. This main vein like the one in the centre of a leaf is called a leader. Unfortunately quartz is only an indicator and can form in many places for different reasons and in different forms. Its worth studying the ways in which these minerals form to be able to identify the formations that have the best possibility of carrying gold.
The outcrop in your photo looks promising, it would be worth sampling around it and directly below where its been weathered as well as further downstream/ downhill to see if more colour can be found.
Best of luck, TGW