3-2 



JOURNAL OF THE KOiAL ILOUTiC DLTUilAL iSOClETY. 



Tiie ]\leiuleli;m oxpocdailoii of iho four forms iu the second genera- 

 tion was, oi' c'e)iiLbo, 'J : 3 : o : 1. The actual nuoibers observed were 

 31: 11: 10: 3. 



Smiilarly, Professor Bateson, by crossing a red sweet pea with a 

 cream-coloured one, obtained ivhiies in the second generation, tlie 

 whites arising fiom the re-combination of the colourless plastids of tlie 

 red sweet pea with the colourless sap of the cream sweet pea. The 

 following diagram (fig. 18) will ihustrate the results obtained by 

 Professor Bateson in his experiment: — 



OWEET TEA 

 Red X Cream 



Ja r™ 1 ' 1 " 



9 Red 3 Red-Cream 3 White iCream 



lilAJZi 9>&isti:d3 ^Mffux 9ea£tkds 9£ajsm yeijUu/ 9iut^ 



Fig. 18. — Showing the origin of a White Sweet Pea by crossing a 

 Eed with a Cream. Re-combination following Mendelian Segrega- 

 tion. (After Bateson, Saunders, and Punnett.) 



An even more interesting result of the same nature has been 

 obtained by Professor Bateson and Mr. E. 0. Punnett by crossmg 

 the Bush and Gupid forms of sweet peas. 



In the first generation (Fi) all the crossbreds were, curiously 

 enough, tall in habit like the ordinary sweet pea. In the second genera- 

 tion (F2), however, there arose in Mendelian proportions tall, bush, 

 ordinary prostrate Gupid and a new variety called ' Erect Gupid ' with 

 a peculiar habit of growth something like box-edging. This result 

 has been shown to be due to the compound nature of these horti- 

 cultural characters, the crossing of which leads to various re-combina= 

 tions in accordance with Mendel's law. The diagram (fig. 19) on 

 page 33 will illustrate Professor Bateson's experiment and demon- 

 strates the true nature of the tall, bush, and Cupid forms of the sweet 

 pea. 



Professor Bateson, Mr. E. G. Punnett, and Miss Saunders 

 have also found that the red colour of sweet peas and ten-week stocks 

 is a compound character due to the presence of two unit-factors, in 

 the absence of one of which the flower is white or cream. They also 

 found that purple colour in sweet peas and stocks is due to the presence 



