The group of evergreen conifers, then, collectively known as silver firs, consists of about thirty species comprised in the genus _Abies_; and these are most easily recognised by the position of the mature cones, which stand erect on the branches, whereas in the other group of true firs, the spruces (_Picea_), they are pendulous in all except two or three Asiatic species. Another mark of distinction is the circular base of the needle or leaf, which, when it falls or is pulled from the branch, leaves a perfectly circular scar; while in the spruces the leaves are set upon little pegs which remain on the twig when the leaves fall. The grey or silvery bands on the under side of the leaf, although it is from these that the tree is called the silver fir, are not an exclusive badge of the genus; for some of the other firs, notably the Manchurian spruce, display similar colouring. The tree known in this country as the silver fir _par excellence_ (_Abies pectinata_) is the loftiest European tree. Probably the extreme height had been attained by one grown in a Bosnian virgin forest, measured by Mr. Elwes after it had fallen, "over 180 feet long, whose decayed top must have been at least 15 or 20 feet more." The silver fir is not a native of Britain, having been introduced about the beginning of the seventeenth century. Its range extends over southern and central Europe, from the Pyrenees on the west to the borders of Wallachia on the east. Nevertheless, it has found a congenial home in these islands, where, if it had ever received scientific handling, it would have been far more highly esteemed for its timber than it now is. Such handling we have never given it; the silver fir has been used indiscriminately in mixed plantation, where, outstripping every other tree in stature, it loses its leader, and sends up a number of heads which get battered by the wind, becoming ragged and unsightly.