NILSSON'S DISCOVERY 89 



to the trade under the name of Zapfenweizen or egg- wheat, 

 alkiding to the curious egg-shape of its heads. The parent 

 form which produced this mutation sported twice afterward, 

 but in both cases its products were muhiple in the beginning 

 and could be brought to uniformity only after some split- 

 tings. 



Besides wheat, the cultures of oats, peas and vetches are 

 seen to produce sports, from time to time, at Svalof. Here, 

 also, the sports are sudden and without preparation or inter- 

 mediates, each of them at once constituting a new type which 

 is as distinct from its allies as any new form found in the 

 fields. Not rarely these changes are found to relate to the 

 very marks on account of which the parent strain had origin- 

 ally been selected, thus constituting a distinct progression 

 of mutability in a previously determined direction. 

 Among oats one of the most prominent novelties of Svalof 

 has originated as a mutation in a pedigree-culture which had 

 remained quite uniform during the 8 or 10 preceding years. 

 It is one of the best black kinds and has, curiously enough, 

 been produced by a white variety. 



In contrast with wheat and oats, the barley has, until now, 

 remained devoid of novelties. This fact is very important 

 from a theoretical point of view. For accidental crosses may 

 be produced as easily in barley as in wheat and oats. Direct 

 extensive experiments, made at Svalof, have estabhshed this 

 fact beyond all doubt. Hence we may conclude that on 

 the experimental fields, with their pure pedigree-cultures, 

 accidental crosses must be extraordinarily rare, even when 

 compared with the rare occurrences in ordinary fields. Evi- 

 dently the conclusion must hold good for wheat and oats as 

 well as for barley, and it speaks for the recognition of their 

 sports as mutations rather than as crosses. In other words, 

 it seems probable that wheat and oats are still in a mutative 

 period, Hke so many of our garden plants, but that barley is 



