The little rose with five leaves gave the Rosaline lace its name. The bundles are another feature. They are the start and finish of each element.
Personally I always put the bundels at the backside. Traditionally these bundles can be seen both at the front and at the backside. Pull the green thread through the orange loop and knot them.
front
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back
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An advantage of the bundles is you don't need to wind the bobbins in pairs. Also very little material is lost.