SPECIES CROSSES IN THE GEXUS NICOTIANA. 221 



The oflfspring of self-fertilized F 1 plants appeared to show 

 clear signs of segregation in floral characters. The range in 

 shape was much more marked than that in size ; in fact the 

 12 plants showed a series ranging from almost the shape of N. 

 alata to almost the shape of N. langsdorfii. In 11 of the plants 

 the style projected very slightly beyond the throat of the 

 corolla ; in the twelfth it projected considerably — ^to an extent 

 varying from ^ to J of an inch. In habit the plants were all 

 very much alike. 



In the case of the cross with typical N. langsdorfii, the 

 recorded measurements of tube length agree fairly closely 

 with the observations of corolla shape. That is to say, the 

 majority of the plants had flowers which differed little from 

 those of N. langsdorfii , except in being somewhat larger, whilst 

 a minority showed a more marked influence from the alata 

 grand-parent. One plant, which flowered late, had a markedly 

 succulent winged stem — a habit unlike that of all its brethren. 

 The 16 plants obtained by crossing the hybrid with N. 

 alata were all practically alike in habit and in the shape of the 

 flowers, the latter being like those of N. alata, but having a 

 less spreading hmb. The segregation in colour, however, was 

 clearly marked (see Table II). 



B.— CROSSES BETWEEN SUPPOSED DIFFERENT 

 VARIETIES OF N. LANGSDORFII. 



The greatest interest relates to the crosses in which the 

 remarkable type E was concerned. 



No self-fertilized offspring have so far been obtained from 

 this variety. Seed was, however, obtained from other varieties 

 of N. langsdorfii when fertilized with pollen from this type. 

 The reciprocal crosses failed. Not much stress is to be laid 

 upon the last-named fact, since the experiments were confined 

 to a single small plant. 



Hybrids were raised between this plant and N. langsdorfii , 

 vars. A and Aa, and with 3 different plants of var. D. All the 

 plants thus obtained appeared perfectly fertile. 



The cross with var. A yielded 10 plants, all closely similar 

 and very near the typical N. langsdorfii. They had rather larger 

 paler yeUow flowers and paler blue pollen, bulged throats to 



