78 Richard H. Boerker 



Black Hills 



Arizona and New Mexico 



Colorado and Wyoming 



Idaho and Montana 



Washington, Oregon, and California. 



It is a striking fact in the case of Pinus ponderosa that the 

 size and weight of the seed and their manner of germination 

 follow exactly this same order. The smallest seeds come from 

 the Black Hills and New Mexico and the largest from California ; 

 the total weight of 500 seeds is least in the case of the Black 

 Hills variety and greatest in the California variety, hence the 

 number of seeds per pound is greatest in the former and smallest 

 in the latter variety. Furthermore, germination begins sooner, 

 the germination period is shorter and the germination curve rises 

 more rapidly in the case of the South Dakota and New Mexico 

 variety than in the case of the Pacific coast variety. Some of 

 these striking relations between seeds and site are also shown by 

 Pseudotsuga taxifolia. This species shows all these relations 

 except those of weight of seed and number of seeds per pound. 

 There seems to be no definite relation in this respect. 



On page 79 the germination curves of the climatic varieties of 

 Pinus ponderosa and Pseudotsuga taxifolia are given and they 

 illustrate very forcibly what has been said above concerning the 

 behavior of these curves. 



In order to determine the effect of the size of the seed upon 

 the size of the seedling shortly after germination, the seedlings 

 were dug up very carefully as they were counted and taken to the 

 laboratory and measured. The total length of the hypocotyl and 

 tap root was taken in each case, the seed being excluded from the 

 measurement. These measurements were kept separate for the 

 small and large seeds and the results are given below : 



Pinus ponderosa {Idaho) Age, 2 Days 



200 seedlings from small seeds averaged 3.07 cm. 



200 seedlings from large seeds averaged 3.90 cm. 



These 400 seedlings were classified according to their total length 

 as follows : 



