630 Varietäten, Descendenz, Hybriden. 



twothirds with D (mostly Single), and about one-third without D; 



2. Three-sixteenths, downy plants, all with B, and nearly all 

 with D (mostly double); 



3. Three-sixteenths, plants with long tomentum, all with C, 

 about two thirds (long black) with D (mostly Single) and about one- 

 third ("Velvet") without D; 



4. Nearly one-sixteenth, smooth black plants, without B or C, 

 all with D (mostly double); 



5. A very few, recessive downy plants, without B, C or D. 

 This hypothesis needs confirmation, especially by crossing and 



back-crossing the constant lines in Fg. M. J. Sirks (Haarlem). 



Chapin, W. S., Heredity in chimeras. (Journ. of Heredity. V. 

 p. 533-546. 1914.) 



Besides a review of current litterature about the interesting 

 Problem of heredity in chimeras, the writer publishes some results 

 of researches in pollinating a pigweed, Atnarantlms retroßexus, 

 that had variegated leaves. The plant was evidently a sectorial 

 chimera composed of green and white tissue. Its offspring consisted 

 of green, white and a few variegated seedlings like the mother 

 plant. Green seedlings and green branches from variegated plants 

 produced only green offspring. White branches produced only 

 white offspring when seif fertilized. Gross fertilization was not 

 attempted. It is likely that the variegated plants which do appear 

 come from a cross between green and white gametes. Probably the 

 heredity of this plant belongs to the type of variegated chimeras 

 of Pelargonium sonale described by Baur. M. J. Sirks (Haarlem). 



Collins, G. N., Nature of mendelian units. (Journ. of Here- 

 dity. V. p. 425—430. 1914.) 



Extensive researches in heredit}'' have indicated that there are 

 many alternative characters which show by the more complicated 

 hybrid ratios that the original characters must be represented by 

 three, four or even more factors. With more than three factors, it 

 has seldom been possible to conduct experiments on a sufticiently 

 large scale to determine whether the ratios are followed with exact- 

 ness or not. The fact that individuals occur in the later generations 

 of the cross which reproduce the character in its original form, 

 and that some of these breed true, at least for several generations, 

 affords evidence that we are still dealing with a complicated form 

 ot the originally simple law. From characters composed of only 

 three or four sub characters, there is now perfect gradation to cha- 

 racters, such as height and weight, where the different stages, if 

 they exist, are completely masked by fluctuations. That we have 

 passed the limit of analysis is certainly no reason to assume that 

 we have passed outside the realm of law. Exemples of coherence 

 and the factoring or subdivision of characters are constant!}' being 

 reported. That typical Mendelian characters are emenable to change 

 through selection is held by some authors (Gastle) to prove that 

 Unit characters are variable, but the author thinks, that these expe- 

 riments may be brought into closer harmony with those of other 

 investigators if the granted "main factor" is looked upon as a rather 

 tenacious group of minute factors similar in nature to the detached, 



