CHAP. IV. CROSS WITH A FRESH STOCK. 113 



ment were crossed -with pollen from another grandchild, and 

 produced five capsules. These contained on an average 31*6 

 seeds, with a maximum in one of forty-nine seeds. The seedlings 

 raised from these seeds may be called the Intercrossed. 



Lastly, eight other flowers on the crossed plants of the last 

 experiment were fertilised with pollen from a plant of the 

 English stock, growing in my garden, and which must have 

 been exposed during many previous generations to very different 

 conditions from those to which the Brazilian progenitors of the 

 mother-plant had been subjected. These eight flowers produced 

 only four capsules, containing on an average 63 '2 seeds, with a 

 maximum in one of ninety. The plants raised from these seeds 

 may be called the English-crossed. As far as the above averages 

 can be trusted from so few capsules, the English-crossed capsules 

 contained twice as many seeds as the intercrossed, and rather 

 more than twice as many as the self-fertilised capsules. The 

 plants which yielded these capsules were grown in pots in the 

 greenhouse, so that their absolute productiveness must not be 

 compared with that of plants growing out of doors. 



The above three lots of seeds, viz., the self- fertilised, inter- 

 crossed, and English-crossed, were planted in an equal state of 

 germination (having been as usual sown on bare sand) in nine 

 large pots, each divided into three parts by superficial partitions. 

 Many of the self-fertilised seeds germinated before those of the 

 two crossed lots, and these were of course rejected. The 

 seedlings thus raised are the great-grandchildren of the plants 

 which grew in Brazil. When they were from 2 to 4 inches 

 in height, the three lots were equal. They were measured when 

 four-fifths grown, and again when fully grown, and as their 

 relative heights were almost exactly the same at these two 

 ages, I will give only the last measurements. The average 

 height of the nineteen English-crossed plants was 45 -92 inches; 

 that of the eighteen intercrossed plants (for one died), 43 '38; 

 and that of the nineteen self-fertilised plants, 50 '3 inches. So 

 that we have the following ratios in height : 



The English-crossed to the self-fertilised plants, as 100 to 109 

 The English-crossed to the intercrossed plants, as 100 to 94. 

 The intercrossed to the self-fertilised plants, as 100 to 116 



After the seed-capsules had been gathered, all these plants 

 were cut down close to the ground and weighed. The nineteen 

 English-crossed plants weighed 18*25 ounces; the intercrossed 



I 



