THE POPLAR. 317 
Ttalian ; P. balsamifera (L.), the balsam ; P. candicans (Aiton), 
the Ontario poplar. 
The three species first-named are propagated by layers, as 
they do not successfully strike root by slips or cuttings. The 
last-named four species strike readily from cuttings. 
Plants grown from layers are necessarily three or four 
times the price of the kinds that grow from cuttings, and 
plants in general raised from cuttings are dearer than those 
produced from seed, 
An idea is common that all plants that are produced from 
layers or slips are apt to become dwarfed or stunted by this 
mode of continuous propagation. However correct this theory 
may be with regard to some plants that are apt to form tap- 
roots, and derive their support from far underneath the sur- 
face, I believe that respecting such trees as poplar, willow, 
lime, etc, their vigour is reduced in no perceptible degree 
by their propagation from layers or cuttings for any length 
of time. 
The mode of propagation by layers is very simple, and is 
detailed under Limz-TrEE. The shoots on a young stool 
commonly double in number every year till about four years 
of age, when a vigorous stool should yield three or four dozen 
plants yearly. After the young layers are removed, it is the 
usual practice to prune and equalize their roots, and place 
them in nursery lines two feet apart, and the plants one foot 
distant, for one year at least, before inserting them into the 
forest. As poplar plants are very apt to overgrow, they are un- 
profitable for nurserymen when there is not a constant demand. 
Poplar Cuitings——The kinds adapted for this mode of pro- 
pagation strike very freely in any ordinary soil, but a sharp 
sandy soil is that which yields the most fibrous roots. Strong 
one-year shoots are commonly employed for cuttings when 
they can be obtained, but two-year-old wood will suit. Cut- 
tings are formed ten to twelve inches long, and are inserted 
in winter or early in spring, about two-thirds into the ground, 
in lines eighteen inches apart, and at the distance of six or 
eight inches in the lines. In summer, when they have sprung 
