THE EVOLUTION AND VARIATION OF FRUIT PLANTS. 15 



species, it must not be inferred that others did not exist, as only 

 a few plants have external substances capable of resisting decom- 

 position. The loose vascular and cellular tissues of the earliest 

 vegetation readily decomposed and were therefore difficult of 

 fossilization. 



The story of the life of fruit plants has been interrupted by long 

 periods of time ; yet there is substantial evidence that fruit trees 

 have usually accompanied the migratory progress of civilization. 

 As long ago as the time of the Crusades, the Romans brought 

 fruit trees, that they did not previously possess, from western 

 Asia, and names were erroneously given. The peach was called 

 the Persian apple ; the cashew the mahogany apple ; the pome- 

 granate the apple of Cartharge. Dr. Lindley grew three rasp- 

 berry plants from seeds discovered buried thirty feet below the 

 surface of the ground and which, it is assumed, had retained their 

 vitality seventeen hundred years. Seeds of beach plums have 

 been found in Maine in a stratum of sand twenty feet from the 

 surface, and trees have sprouted from the earth upon which the 

 sand had been strewn. Fruit germs may have retained their 

 vitality buried beneath the glacial rubbish, as seeds are occasion- 

 all}' found thus reposing in a dormant condition. Wild species 

 sometimes appear in situations where they have been previously 

 unknown, but after a change has been produced in the physical 

 state of the soil. The drift deposits may have been the vast 

 granary in which Nature preserved her store of seeds through 

 the long rigors of a geological winter. 



Historical time is regarded as so small a fraction of the age of 

 the earth, as to make the date of the origin of fruit plants obscure ; 

 but an early development of flowers must have taken place in 

 order to perpetuate the species ; and Nature must have cared for 

 the pulp of the fruit sufficiently to protect the inner seed and 

 assist in its development and distribution. The long series of 

 fossiliferous deposits which form the connecting links between 

 the present and the remote past have demonstrated that different 

 specific and generic types of vegetable life followed one another 

 in successive periods ; that fruits with which we are familiar were 

 not always in existence but were preceded by numerous races 

 differing from them. At a certain definite period the life of a 

 fruit plant had a beginning. It is probable that its existence 

 depended on parental rather than spontaneous generation, yet the 



