Pine trees are popular. OF late years no class of trees has been so popular with the generality of those who plant for ornament as the Pine tree (or Conifera). They are so separated in their structure from other plants as to form a Class rather than an Order, and embrace, when the name is used in its more comprehensive sense, as is now usual, several very distinct types. In past ages in the history of the globe they formed a more predominant feature in the vegetation of all latitudes than at present; and it is probable that if our knowledge of these fossil forms were more complete there would be found to have been even greater variety among them than among those that remain to us, showing them to bridge over the gap between such flowerless plants as the club-mosses, and the ordinary fruit-bearing, or angiospermous, flowering plants, more completely than we can at present demonstrate.