THE HOMOLOGIES OF FRUITS 269 



such as are represented in the following two tables. The story 

 of the Acorn, viewed from the standpoint offered by the role 

 taken by the water-contents, seems to be particularly suggestive, 

 especially in connection with the tendency to vivipary at times 

 displayed, a subject discussed in Chapter XIX. Some of the 

 most fascinating problems bound up with plant-life lie behind 

 the phenomena of the drying fruit ; and none are more 

 important than that connected with germination on the plant. 



In this respect the story of the decrease in the water- 

 contents of the Ivy berry {Hedera Helix)^ as it grows steadily 

 from the autumn through the winter, finally dropping to the 

 ground in the spring, and often with one or more of its seeds 

 germinating, is particularly interesting. This progressive 

 decrease is clearly shown in one of the following tables. But 



Table showing the Difference in the Water-Contents of Im- 

 mature AND Mature Fruits, as indicated by their Loss of 

 Weight when dried in Air under ordinary Conditions. 

 (By mature fruits are meant those that are full-grown and moist, contain ripe seeds, 

 and show no signs of drying. By immature fruits are usually meant those that have attained 

 nearly the full size and weight, but have seeds with contents not set or incompletely 

 developed. For the berries of Sambucus nigra another explanation is required, as is 

 given below. ) 



* The browning acorn is taken as the mature stage (see Chapters XIV and XIX). 

 t In the case of Elder berries the difiference is due to the formation of sugars in the 

 ripening fruit, as explained in an earlier page of this chapter. 



