137 



0. Hairiness. 



7. Form, appearance and size of spike or panicle. 



8. Development of spikelets, glumes and spikelet clusters. 



B. Physiological Characters 



1. Hardiness 



2. Time of maturing. 



3. Resistance against disease 



4. Withering down of leaves. 



5. Aftergrowth. 



6. Stiffness of straw. 



A. Regarding Morphological Differences in Grasses 



Great differences are to be found between different types of Timothy in 

 regard to length of stem, even when such types are grown under essentially 

 the same conditions. Thus, careful measurements of a large number of 

 individuals made by Witte in the summer of 1908, revealed a variation in 

 this character of from 50 to 130 c.m. (82, p. 6). 



Investigations made with a view to determining the hereditary qualities 

 of different types has shown that while it is practically impossible to maintain 

 permanent constancy in such cross-fertilizing plants as grasses, hereditary 

 gradations in the length of stem in Timothy undoubtedly occur. One of 

 the most striking of these gradations studied at Svalof was a dwarf type 

 (No. 309, 1907), which maintained its dwarf habit in succeeding generations 

 in a striking manner. 



In certain other grasses such as Orchard grass and Tall Oat grass, 

 different types in regard to length of stem have also been noticed, although 

 the differences have not been so great as in the case of Timothy. 



It has been found difficult to determine whether or not there exist 

 hereditary differences between different forms of the same species in regard 

 to degree of stooling, although investigations seem to indicate that such 

 differences do exist. 



