Professor Sargent enumerates eleven species of poplar as indigenous to North America, some of which, such as the Balsam poplar (_P. balsamifera_), the Ontario poplar (_P. candicans_), and the Carolina poplar (_P. angulata_), have risen to large dimensions in British woodland; but to follow out these, and their constantly recurring hybrids, would far exceed the limits of this paper. There are many Asiatic species also, one of which (_P. euphratica_) we are now taught to recognise as the "arabim" whereon the captive Jews hung their harps (Psalm cxxxvii. 2). The weeping willow, named by Linnæus _babylonica_, is not found in the valley of the Euphrates. It is time that British planters should recognise the importance of the more vigorous species of poplar as rapid timber-producers, thriving in cold, wet ground where no other crop could be raised so successfully. A useful example is set in this matter by French cultivators, who plant more poplars than any other tree. Moreover, all the species are most easily propagated and handled in planting. They should be grown from cuttings; it is futile to attempt raising them from seed--a most uncertain process, and unsatisfactory when it succeeds, cutting-grown plants being far more vigorous than seedlings. The Birch Bentham and Hooker recognised only two species of birch as indigenous to the British Isles--namely, _Betula alba_, the common birch, and _B. nana_, an insignificant shrub which grows in the Scottish Highlands. Messrs. Elwes and Henry, however, in their great work give specific rank to each of the two forms of the common birch prevailing in this country. It is certainly strange that the difference between them has not received more attention from foresters, seeing that one is a far more valuable tree than the other. Whether they be permanent species or merely racial varieties matters not for practical purposes; but it matters much that the better kind be planted where conditions are favourable for it. The commoner and less desirable of the two forms has been named _B. pubescens_, owing to the young shoots being clothed with down, sometimes so minute as to require a lens to show it. This and the habit of the tree are the only constant marks of distinction from the other form, which is named _B. verrucosa_, because the shoots, though shining and perfectly free from down, are studded with minute _verrucæ_, or warts, easily discernible by the naked eye. I have found in southern Norway, where the two reputed species grow together, intermediate forms which are no doubt natural hybrids.