They're full of a toxic sap called mucilage, so when the flowers are cut, sap flows from the stem.

里面充满了一种叫做粘液的有毒树液，因此当花朵被切开时，汁液就会从茎中流出。

These caused the tree to bleed or give off sap; all during the summer the trees were chipped regularly, the sap flowing down into the box, where it was collected.

这使树流血或流出汁液；整个夏天，树都定期被砍，汁液流到盒子里，在那里收集的。