crossing of the orange and lemon, i. 399, ii. [365];
effect of foreign pollen on maize, i. 400;
spontaneous crossing of oranges, ii. [91];
monstrosities a cause of sterility in plants, ii. [166];
seeding of ordinarily seedless fruits, ii. [168];
sterility of the sugar cane, ii. [169];
tendency of male flowers to become double, ii. [171];
effects of selection in enlarging fruit, &c., ii. [217];
variation of the orange tree in North Italy, ii. [256];
naturalisation of the orange in Italy, ii. [309].