"This is a very young birch," continued their governess, "and you see how slender and graceful it is; also that the bark, or 'skin,' is very dark. For this reason it is called the black, or cherry, birch, and also because the tree is very much like the black cherry. It is also called sweet birch and mahogany birch; the _sweet_ part you can probably understand, and it gets its other name from the color of the wood, which often resembles mahogany and at one time was much used for furniture. There are larger trees of the same kind all around us, and I should like to know if anything else has been noticed besides the twigs of this little one."