192 
SELF-PRUNING OF TREES. 
Agriculture in advising the publication of the whole of their interest¬ 
ing notes in a separate form. As the writers are both good practical 
botanists, they cannot fail to elicit some information either of the 
habits or culture of North American plants which may be generally 
useful. 
The Sweet Lemon. —It is said, that in the Azores, and particu¬ 
larly in the neighbourhood of St. Michael’s, the sweet lemon is produced 
by grafting the sour lemon on the orange. If this be a fact, but of 
which we have strong doubts, it is the only instance known that the 
qualities of the fruit of the graft can be altered by those of the stock. 
That sweet lemons are grown in the Western Islands, as well as in 
Italy, and that they are much used in the former country, is true ; but 
we must venture to deny that they are originated by the above men¬ 
tioned means. 
Premiums offered by the Highland and Agricultural 
Society of Scotland. —For planting not less than one hundred and 
fifty acres within a period of five years successfully.—For collecting 
the seeds of the Pinus sylvestris (Scotch fir) from native trees.—For 
raising larch from native seed.—For the introduction of new forest 
trees.—For the introduction of seeds of forest or ornamental trees 
likely to succeed in Scotland.—For the more extended introduction of 
known species of the fir tribe already in Britain. Under the last head 
attention is particularly directed to Araucaria imbricata , Pinus pon- 
derosa, Lambertiana, and Sabiniana; to Abies Douglasii nobilis, 
grandis, and Menziesii; and to Taxodium sempervirens, which last 
is abundant in the vicinity of St. Francisco and throughout the low 
sandy plains of California. The Society also offers premiums for col¬ 
lecting the seeds of the following native leguminous plants, viz. Vicia 
sepium, V. cracca , V. sylvatica, Lathyruspratensis, and Lotus major; 
also for saving the seeds of Italian rye-grass. 
The premiums vary from twenty-five to four sovereigns ; or medals, 
or pieces of plate of equal value. 
November 6th , 1834 . 
On the self-pruning of Trees. —According to promise, I herewith 
send you some specimens of self-pruning; they are sprays from the black 
poplar. Mr. Ballard, who has written a treatise on self-pruning, says, 
“ Trees have the power of pruning themselves; all useless branches die 
and drop off.” Now, with regard to the black poplar, living branches are 
detached annually, in October, in considerable quantities; their attach- 
