52 



European "White Alder" sample contained twice as much Black 

 Alder as White Alder. When the tests were continued in the fol- 

 lowing year the same conditions were repeated, and this was con- 

 firmed each year, for far the greater part of the trade white alder 

 seed is more or less admixed with black alder. 



THE HEART-LEAVED ALDER ALNUS CORDATA. Repeated 

 tests often give a very good idea of the reliability of the collector 

 and the quality of the seed. In a number of years I received the 

 very rare seed of A. cordata from a French collector, and the seed 

 was always of only moderate real value and often quite worthless. 



In three successive years the germination tests proceeded as 

 follows: 



Germination in per cent after 5 10 30 60 100 days 



1905... 8 20 30 

 1906... 8 19 56 



1907... 2 9 12 



That the seed of each of the three years was furnished from 

 the seed of the same year, is proved especially by the gradually 

 falling germinating energy; indeed the seed was apparently already 

 one year old in 1905, for I received for the first time in the year 

 1910 11 from an Italian collector a small lot of A. cordata which 

 germinated fast and well and showed what this seed can and ought 

 to be, since the test proceeded as follows: 28 %, 62 %, 72 / and 

 72 %, in 5, 10, 20 and 30 days respectively. 



BIRCH BETULA VERRUCOSA and BETULA ODORATA. The 

 trade in these seeds has also received much benefit from my co- 

 operation with the Seed Testing Institution. During the earlier 

 years one was pleased with a germinating capacity of 10 % or 

 even less, as the mean germinating capacity of Betula verrucosa 

 amounted in the first 15 years to 16 %, in the last 10 years to 29 % 

 and in the last 5 years to 44 %. 



Of B. ODORATA I have always had only northern seed, of Fin- 

 nish, Norwegian or Swedish origin, and it was really always of 

 good quality, since the lowest found germinating capacity was 

 1 1 % against 2 % for the Mid-European seed, and only 4 out of 23 

 Scandinavian samples gave but 11 to 15 / . The mean germinating 

 capacity for the whole period of years was 37 / against 23 % for 

 the Mid-European seed. 



