The only tool absolutely necessary is a pair of forceps, although a hand-lens is often helpful.
This difference of the fibres is best observed with a hand-lens.
It is very small; but once studied may thereafter be easily recognized by a hand-lens.
In some large twigs the eye unaided will serve to find the tip-scar, but with the smaller twigs a hand-lens is necessary.
With the aid of a hand-lens, a whole series of most exquisite little hooks will be discovered.