1 8 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



SO many sports and hybrids have been raised, told me that 

 there existed in 1868 a Hne of female trees of Populus nigra var. 

 betulifolia, alongside some Lombardy poplars, and that fifteen 

 seedlings of fastigiate habit were found, which constituted the 

 original stock (both sexes occurring). One of the original trees, 

 which is a male, measured 74 feet high by 5 feet in girth in 1908. 

 This tree can only be distinguished from the ordinary Lombardy 

 poplar by its hairy twigs and petioles. It is doubtful if it is more 

 vigorous, but its growth can be seen at Kew and at Glasnevin, 

 where there are excellent specimens of this and most of the other 

 remarkable poplars. 



The fastigiate habit may occur as a sport in any species of 

 tree. Some are still very rare in cultivation, as the fastigiate 

 beech, which is only known as a single tree at Dawyck, and 

 the fastigiate Scots pine, the original example of which is at 

 Dryburgh. Amongst the cypresses and junipers, fastigiate 

 seedlings are more numerous than in other genera, and appear 

 to breed true to the habit. Lord Selborne gathered from an 

 upright Mediterranean cypress at Scutari in 1884 two or three 

 cones, which lay forgotten in a drawer till 1895, when their seeds 

 were sown. Seventeen seedlings resulted, all like the parent in 

 habit. These were about 6 to 15 feet in height at Blackmoor 

 in 1910. With an increase from seed in the number of fastigiate 

 individuals, as occurs in the cypress, we see the transformation 

 from a sport to a constant form, which, if more suitable than the 

 spreading ordinary form in some environment, might become by 

 selection a geographical variety. 



In North America, east of the Rocky Mountains, there occurs 

 one species of black poplar, divisible, like the European species, 

 into distinct geographical varieties. This widely-distributed 

 American poplar has been identified by American botanists with 

 Populus deltoidea, Marshall, an old name to which is attached 

 a vague description. The first certain description of any form 

 of the species was given under the name Populus monilifera, 

 Alton, a type specimen of which can be seen in the British 

 Museum ; and I adhered to this name in Trees oj Great Britain, 

 vii., 1807 (19 13) ; but as the business of nomenclature is to get 

 some name fixed to a species, I think it now better to adopt 

 the name favoured by American botanists. 



There are three distinct forms of the American black poplar 

 in the wild state, all of which have identical floral characters. 



