216 lock: 



We find, then, both in crosses between varieties of Niootiana 

 langsdorfii, and in those between N. langsdorfii and N. alata, 

 three pairs of characters — one of shape and two of colour — 

 whieh show marked segregation. And we find moreover in 

 F2 ratios, which at least suggest that this segregation is taking 

 place in characteristic Mendelian fashion numerically. The 

 characters segregate independently, and all possible combina- 

 tions of them have been seen. 



IV.— GENERAL FEATURES OF N. LANGSDORFII 



CROSSES. 



A.— CROSSES WITH OTHER SPECIES. 



These are of special interest as affording evidence with 

 regard to the behaviour of the progeny of crosses between 

 forms of unquestionable specific distinctness, in whiclx the 

 hybrids appear to be almost perfectly fertile. 



Evidence with regard to the segregation of certain characters 

 has already been given. 



(1) N. alata x N. langsdorfli, var. C. (No. 76/07.) 



Except that one plant had white pollen (the remainder 

 pale-blue), all the 10 hybrids reared were closely similar to one 

 another. They were decidedly intermediate in general habit 

 and appearance, but considerably taller than either parent. 

 The corollas showed a marked bulge, but were otherwise 

 intermediate in shape and size. 



In F 2 the following were grown to the flowering stage :— 



No. 76/07 self -fertilized = No. 74/08, 11 plants. 



No. 76/07 X N. langsd. var. C = No. 102/08, 28 plants. 



N. alata X No. 76/07 = No. 104/08, 38 plants. 



No. 76/07 X N. alata = No. 105/08, 40 plants. 



No. 76/07 X N. langsd. (A) = No. 101/08, 36 plants. 



[For Table VI., see p. 219.] 



In the accompanyitig Table (VI.) the length of the tube of a 

 typical flower of each of the above plants is recorded. The 

 thoroughly intermediate character of the cross-bred type is 

 here clearly indicated. There is cet'tainly no evidence of 

 segregation in this table. We may go further, and point out 



