R. N. Salaman 43 



2. Length of tuber is dominant to " roundness." 



3. Depth of " eye " is dominant to " shallowness." 



4. Purple is dominant to red in the tubers. 



5. Red is dominant to white, but is dependent on the presence of 

 two factors in addition to a chromogen. 



6. S. etuherosum is not subject to the same laws of dominance as 

 the domestic varieties of potatoes. 



7. That amongst the seedlings of S. etuherosum occur some which 

 are at present immune to the attacks of Phytojihthora infestans. 



8. That immunity to the attacks of Phytophthora infestans is in 

 S. etuherosum a recessive character. 



9. S. etuherosum may be a hybrid and, if so, its parents are possibly 

 native species. 



I take this opportunity of tendering my thanks to my head gardener, 

 Mr E. Jones, for the assistance he has rendered, and the great care he 

 has shown in the raising of the seedlings. 



DESCRIPTION OF PLATES. 



PLATE I. 



Tubers of seedlings of Sutton's "Flourball" selfed. "Rounds" are — Nos. 40, 89, 92, 

 118, 132, 138, 155, 156, 162, 185. 



PLATE II. 



Family of seedlings of parent A selfed. The majority of the tubers are normal "rounds"; 

 the least typical "round" has been chosen to represent each individual root. On 

 Plates IV. and V. can be seen the sister tubers of the more abnormally shaped 

 "round" tubers. 



PLATE III. 

 A family continued. 



PLATE IV. 



All the available tubers of each root crop are shown of those individuals who vary from 

 the typical " round." In all cases one or more typical " rounds " occur in each 

 root crop. 



PLATE V. 



Same as Plate IV. No. 100 is probably a stray plant and not a member of this family. 



