114 Selection Docs Not Lead to Origin of Species. 



sequently extended over Germany and the north of 

 France/ and is now admitted to be one of the best Euro- 

 pean cereals.^ Ears and grains are about twice the size 

 of those of other sorts of rye; they ripen earher and, 

 what is far more important, give a much larger return 

 per acre.'^ 



In this case as in the previous ones, incessant selec- 

 tion and plenty of manure are the conditions which are 

 necessary to keep the race at the level which it has 

 reached. Avidity for manure is, according to Risler- 

 RiMPAU, a feature which distinguishes improved races 

 from constant varieties.^ 



This improvement of races, ^ as now practised in 

 agriculture, has, however, of late appeared in a wholly 

 different light through the practical researches of Dr. 

 HjALMAR NiLSSON of the Swedish Agricultural Experi- 

 ment Station at Svalof.^ 



He discovered that cereals and other agricultural 

 crops consist of far larger numbers of elementary spe- 

 cies, than was hitherto supposed. Out of every so-called 

 variety hundreds of such minor types can be isolated, 

 which as a rule prove constant at once after such isola- 

 tion. Exceptions are offered by casual hybrids, which 

 may split up, after which the products may, however, 



* ScHRiBAUX, Seigle de Schlanstedt, Almanach du Cultivateur, 

 1892, p. 66. 



^ See, e. g., the seed catalogue of Vilmorin-Andrieux in Paris. 



^ The rye of Rimpau has since been surpassed by that of Pctkus, 

 produced by Von Lochow (Note of 1908). 



* Weizenhaii, p. 80. 



^ The following paragraphs were added to the translation, 1908. 



* Cf. Sveriges Utsddes forcnings Tidskriff, Years 1892-1907, Vol. 

 T-XVI, and Die Svalofcr Mcthodc zur Veredlitng landivirthschaft- 

 licher Kiiltiirgewdchse und ihrc Bedeutung fiir die Selektionstheovie, 

 Archiv fiir Rassen- und Gesellschafts-Biologie. Jahrg. 3, pp. 325-358. 

 1906. 



