4 Descendenz und Hybriden. — Morphologie und Teratologie. 



fixirten) und aitionomen (variablen, nicht fixirten) Merkmalen, 

 wie ihn Pfeffer konstruirt, fällt demnach ganz fort. Die Ge- 

 sammtheit der Veränderungen alier Merkmale (die als Potenzen 

 der spezifischen Struktur vorauszusetzen sind) unter dem noth- 

 wendigen Einfluss der wechselnden äusseren Bedingungen heisst 

 Variation. Die Aufgabe der experimentellen Variationslehre 

 liegt darin, den gesamten Umfang der Variation für jede Spe- 

 cies festzustellen und jede Variation als nothwendige Folge 

 äusserer Einflüsse nachzuweisen. O. Damm. 



Lock, R. H., Plant Breeding. (Circulars and Agricultural 

 Journal, Royal Botanic Gardens, Ceylon. Vol. II. 1904. 

 No. 22. p. 357 -365. No. 26. p. 415—421 and No. 27. 

 p. 423—430.) 



These three circulars are devoted to a brief description of 

 the work on plant breeding in Ceylon, on which the author 

 was engaged for two years. Part 1 gives an account of some 

 of the theoretical principles of the subject and cites instances 

 of „individual" and „definite" difierences. Mendel's obser- 

 vations on inheritance in peas are summarized. 



In the second part the practica! processes in plant breeding 

 are discussed, selection, manuring and cross-breeding being 

 successively dealt with. Under the latter head practical notes 

 on methods are included founded on the results of the author's 

 experience in Ceylon. The value of accurate records is in- 

 sisted upon. 



An account of the actual results obtained with peas forms 

 the subject of the third part. Peas were selected for experi- 

 ment because they form a typical garden crop already repre- 

 sented in Ceylon by an inferior variety, which it was hoped 

 might be improved by crossing with imported strains, although 

 the latter are not by themselves well suited to the ciimate. 

 After giving Vilmorin and Andrieux's Classification of peas 

 and summarizing the behaviour of characters on crossing, brief 

 notes are recorded of the Ceylon experiments followed by 

 an account of the new forms obtained, some of which appcar 

 likcly to be of greater economic value than the parent forms. 

 The paper closes with practical remarks on the cultivation of 

 peas at the elevation of the Botanic Garden at Peradeniya, 

 about 1,500 feet. W. G. Freeman. 



BiTTNER, K., Ueber Chlorophyllbildung im Finstern 

 bei Krvptogamen. (Oesterreichische bot. Zeitschrift. 

 1905. p.' 302 ff.) 



Die Verfasserin stützt sich in ihren Angaben zum Theil 

 auf eigene Untersuchungen, die sie in dem pflanzenphysiologi- 

 schen Institut an der deutschen Universität in Prag angestellt 

 hat, zum Theil hat sie das, was in der Litteratur über das ge- 

 nannte Thema zerstreut vorhanden ist, gesammelt und über- 



