160 



A great variety of panicle types have been found in Orchard grass. 

 These are distinguished chiefly by: 



(a) Length. 



(b) .Length and position of the lower branches at time of maturity. 



(c) Stiffness both of rachis and branches. 



(d) Size of the spikelet clusters. 



As in the case of Timothy, ft long line of hereditary gradations are to be 

 found between the shortest and the longest panicled types as indeed between 

 types which are distinguished by other characters. Modifications, due to 

 such factors as soil and season, are also very much in evidence in the case of 



Photo by H. Witte. 

 FIG. L. Orchard Grass: Average panicles from different biotypes (82, Fig. 25). 



this grass, a fact which renders it difficult to always say with assurance 

 whether or not a given individual represents the peculiar characteristics of 

 a distinct biotype, or whether it is simply a temporary deviation (modifi- 

 cation) from the biotype to which it actually belongs. 



Variations, or more properly " gradations", are also to be found in the 

 character of the spikelets. The glumes may differ in form and color as well 

 as in the length and character of the awn which they bear. Different types 

 of seed, both as regards color and form, are likewise more or less abundant. 



B. Regarding Physiological Differences in Grasses. 



Most cultivated grasses are fully hardy at Svalof although at the 

 northern station at Lulea, Ulander has found marked differences to exist 

 between different lines within the same species (77, p. 41). Witte has also 

 made some interesting observations to the effect that different lines of Orchard 

 grass originating from different countries have displayed different degrees 

 of hardiness when tested at Svalof. Thus, types obtained from Denmark 

 were found to be almost universally more delicate than those originating 

 from Switzerland (82, p. 56). 



