I want to know the answer to the following question:
In wood from a willow tree, what would you need to use to see the tiny vessels?
All the background I'm provided with is that "The water conducting capability is mostly taken care of by vessels: in some cases (oak, chestnut, ash) these are quite large and distinct, in others (buckeye, poplar, willow) too small to be seen without a hand lens.". Is that enough to answer the question?