18 "■ Rofjues" in Ctdiiuuij Pais 



all types. In 1913 from these were raised 15 families. Some of them 

 contained rogues, but one large family was free from them. From that 

 family in 1914 we raised 29 families, of which 22, aggregating 1122 

 plants, were all types. The remaining 7 families each contained a 

 single aberrant jjlant, the total being 357 types and 7 aberrants; or 

 51 : 1. This is the strain of E. G. which has thrown fewest rogues. 

 Where the proportion of aberrants is so small it is evidently impossible 

 to be confident that plants which give even 100 offspring all typical 

 were incapable of throwing rogues. 



In the case of D. A. a much nearer approximation to purity was 

 made. From selected type plants in 1911 about 3300 plants were 

 raised in 1912, all typiciil. From selected plants among these about 

 12,000 were raised in 1913, and no abeiTant individual was found among 

 them. In dealing with these large numbers of plants it will be under- 

 stood that the characters of evei-y single plant cannot be positively 

 guaranteed under the conditions of the experiment, for in all such crops 

 there are some plants that have not grown well and might conceivably 

 be aberrant, but we have conlidence that no well-grown jjlant departed 

 from that type, and only the finest plants were used as parents. From 

 eight well-grown families in 1913 (containing, as we have said, no 

 rogues) the seeds were sown in 1914, giving about 39,000 plants, and 

 among them again no rogue was seen. 



One family however had the following history. A type plant in 

 1911 gave a family in 1912, about 60 plants, all types (except two 

 doubtful, which gave only types in 1913). A typical plant in this 

 family gave about 60 in 1913. The best grown of these, all strictly 

 typical, were harvested en masse, and their seed was sown in 1914. 

 The crop consi.sted of about 5100 plants of which six were rogues of an 

 extremely low grade, being moreover sterile^. 



Plants of a similarly very low rogue were seen as great i-arities in a 

 crop of Gradus growing for seed in Essex. They, also, were apparently 

 sterile. A leaf of one of them is figured on Plate XI, fig. 9, together with 

 a leaf of the type of Gradus, and one of the ordinary rogues in the crop. 



The whole course of the evidence is thus cpiite inconsistent with 

 the supposition that the rogues appear as regular recessives in the 

 ordinary sense, and we are convinced that the commercial growers are 

 perfectly right in asserting that a strain may breed true for a while 

 and then throw rogues. The question arises, can such rogues have been 

 introduced by insect-fertilisation ? As a very gi-eat rarity accidental 



1 See p. 29. 



