236 



The Pedigree Families. 



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cies or as a variety. Our business is to test its constanc}- 

 by experiment. But tbe result of this will not help us 

 to decide between species and variety. 



^^j^gfy* ^v>»^ 



Fig. 45. Oenothera nanella. A thinly and a densely leaved 

 individual on one of the first days of the flowering pe- 

 riod. The plants were about 15 and 20 cm. high, whereas 

 annual plants of O. Lamar ckiana begin to flower when 

 they are about one meter high. 



If a form proves to be constant but is distinguished 

 from another form onlv bv a single character, it is re- 



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