Principles of Heredity 161 



The peas were selected for their colours, &c., from the third 

 year's sowing in 1869 of the produce of a cross in 1866 of the 

 early round white-seeded and white-flowered garden variety 

 " Ringleader," which is about 2^ ft. in height, fertilised by the 

 pollen of the common purple-flowered "maple" pea, which is 

 taller than " Ringleader," and has slightly indented seeds. 

 I effected impregnation by removing the anthers of the seed- 

 bearer, and applying the pollen at an early stage. This cross 

 produced a pod containing five round white peas, exactly like 

 the ordinary "Ringleader" seeds" 55 '. 



In 1867 I sow T ed these seeds, and all five produced tall 

 purple- flowered purplish-stemmed plants t, and the seeds, with 

 few exceptions, had all maple or brownish-streaked envelopes 

 of various shades ; the remainder had entirely violet or deep 

 purple-coloured envelopes |: in shape the peas were partly in- 



' Around white ? x grey a giving the usual result, round, "white" 

 (yellow) seeds. 



t Tall heterozygotes, with normal dominance of purple flowers. 



Here we see dominance of the piymented seed-coat as a maternal 

 character over white seed-coat. The colours of the seed-coats are 

 described as essentially two : maple or brown-streaked, and violet, the 

 latter being a small minority. As the sequel shows, tbe latter are 

 heterozygotes, not breeding true. Now Mendel found, and the fact 

 has been confirmed both by Correns and myself, that crossing a grey 

 pea which is capable of producing purple leads to such production as 

 a form of xenia. 



We have here therefore in the purple seeds the union of dissimilar 

 gametes, with production of xeuia. But as the brown-streaked seeds 

 are also in part heterozygous, the splitting of a compound allelomorph 

 has probably taken place, though without precise statistics and 

 allotment of offspring among the several seeds the point is uncertain. 

 The colour of seed-coats in " grey " peas and probably " maples " also 

 is, as was stated on p. 150, sensitive to conditions, but the whole 

 difference between "maples" and purple is too much to attribute 

 safely to such irregularity. " Maple " is the word used to describe 

 certain seed-coats which are pigmented with intricate brown mottliugs 

 on a paler buff ground. In French they are perdnx. 



B. 11 



