Angewandte Botanik. 223 



the production of wheat combining heavy yield with "strength" of 

 flour. Although final proof of the segregation of the characters of 

 high and low yield has not yet been obtained, there are indications 

 that high yielding capacity is inherited, and that it may be a unit 

 character. The question of high yield is intimately connected with 

 the power of resisting parasitic disease, and in this connection 

 Biffen's well known experiments in breeding races relatively immune 

 to the attacks of Puccinia gliinianan are referred to. The evidence 

 with regard to immunity from the Black Rust, P. graminis, is 

 not yet complete, but it would seem reasonable to suppose that it 

 can also be brought under control. 



Dr. Saunders describes some of the experiments which have 

 been carried out at the Canadian Experimental Farms, and descri- 

 bes some of the new strains which have been produced. He is not 

 able to agree with the view which regards strength and weakness 

 of the flour as a pair of IVlendelian unit characters. 



Professor Zavitz and Mr. Klinck deal chiefly with the methods 

 and results of experiments in the selection of Wheats and other 

 cereals. 



Dr. Stapf deals with the history of the Wheats in the light of 

 Dr. Aaronsohn's discoveries in Palestine. The wheats are traced 

 to four primitive types: 1) the Einkorn to Triticimi aegüopoides , 

 with is original home in Asia Minor and the north-eastern 

 Balkans; 2) the Emmer and the Hard Wheats, to T. dicoccoides,. 

 in Palestine; 3) the Soft, and probably also the Dwarf Wheats to 

 a still unknown species; and 4) the Spelt, to T. cilindricurn , in an 

 area extending from Bulgaria through Roumania to Southern 

 Russia. Dr. Stapf points out the desirability of actively continuing 

 the search for new wild forms, and of tracing the distribution of 

 primitive wheats. There can now be no doubt where to look for the 

 former, while of the latter, many are no doubt still in cultivation, 

 as for instance in the Balkan Peninsula and in Asia Minor, 

 and if not secured in the near future may be lost forever. 



R. P. Gregory. 



Snell, K., Untersuchungen über das Vorkommen ge- 

 wisser Ackerunkräuter (Deutsche landw. Presse. XXXVII. 

 p. 226. 1910.) 



Die Beobachtung, dass Kornblumen {Centaurea Cymius) und 

 Kornrade {Agrostejnma Githago) im allgemeinen nur in Getreide- 

 feldern vorkommen, dagegen nur selten auf Rüben- und Kartoffel- 

 äckern, veranlasste Verf. den Ursachen dieser Bevorzugung der 

 Getreidefelder nachzugehen. Angestellte Aussaatversuche zur Prüfung 

 der Frage, ob die Keimung der Samen genannter Unkräuter durch 

 Rüben und Kartoffeln ungünstig beeinflusst würde, führte zu einem 

 negativen Resultat. Danach kann nur die verschiedenartige Bebau- 

 ung der verschiedenen Aecker als Ursache der beobachteten Er- 

 scheinung angesehen werden: Kornblume und Kornrade gehören 

 zu den reinen Samenunkräutern, die durch Schaufeln und Behacken 

 leicht völlig zu vernichten sind, wenn sie dagegen, wie in Getreide- 

 feldern ungestört wachsen können, kommen sie zur kräftigeren Ent- 

 wickelung und erhalten sich durch die grosse Menge der gebilde- 

 ten Samen. Beschattung wirkte auf dass Wachstum der Kornblumen 

 ungünstig ein, sie finden sich ja auch in der Tat am Rande eines 

 Kornfeldes in grösster Menge. 



