The reddish-brown color is due to the coating of fibrils that covers the cap.
If the coating has spiny hairs, as in the Chestnut and Beechnut, the whole is a bur.
The necessity for this coating of sulphur or paraffin you will understand by an experiment.
This is with the object of securing great uniformity in the coating.
She came down to them and found that the fur was a ...