SINGLE SEED SELECTION. 



7 



home-grown seed coincided with the serious outbreak of larch disease 

 which has been unhappily so prevalent. 



There are certain considerations also which seem to make it probable 

 that larch seed hardly has the chance of ripening properly in Scotland. 

 The natural home of the larch in Europe has been carefully described 

 in KiECHNEB, LoEW and Sciieoter's recent work. 



It extends from latitude 44^ 30' N. in French Dauphine to Kron- 

 stadt. The northernmost point is about Gabriz. 



In one important point the climate of all the area so outlined differs 

 very widely from that of Scotland. 



No part of Caledonia enjoys so much as 1,400 hours of sunshine in 

 the year, whilst in the larch's natural country there must be every- 

 where at least 1,700 hours and in many districts even 2,000, possibly 

 2,200, hours of sunshine. 



Without more exact information as to the sunshine conditions in 

 the critical period during which the larch seed is maturing and devel- 

 oping, it is impossible to be dogmatic on the subject. 



It would be interesting to compare a large series of samples of Scotch 

 and Continental seed in order to find whether there is a marked differ- 

 ence in respect of size and weight of seed. 



Certain Scotch samples which I have myself examined were un- 

 doubtedly lighter, smaller, and not so well developed as the Continental 

 ones selected for comparison, but, naturally, a very large series of obser- 

 vations are required before anything definite can be said on the 

 subject. 



I am afraid also that in many cases Scotch seed is neither collected 

 with the same care nor cleaned with the skill and method which pre- 

 vails in Germany. 



On the whole it certainly seems advisable now to choose the best 

 Continental larch seed. 



I have been able to compare the results for a few plantations in 

 which the origin of the seed has been recorded. 



These reports are unanimous regarding the greater prevalence of 

 disease in those woods which were grown from Scotch seed. In fact. 

 Continental and especially Tyrolese seed is preferred by all those 

 whom I have consulted, chiefly for this reason, but also because, in 

 their opinion, the germination results are much better and the seed is 

 much cleaner and better preserved. 



The Tyrolese seedlings in the nursery seem, however, to be more 

 affected by frost when in the nursery than home-grown seed. 



If this last observation is justified by further experience, it is an 

 interesting case of hereditary influence. Engler in the paper already 

 referred to mentions that the seedlings of those Sycamores which had 

 lived at very high altitudes in the Alps inherited their parents' periods 

 of coming into foliage and of shedding the leaves. 



But the main point which I wish to make is that there is an obvious 

 advantage in selecting the very finest, largest, and best seeds, especially 

 in the case of forest trees. It is almost certainly the case that, if this is 



