286 



STUDIES IN SEEDS AND FRUITS 



water when full-grown and before dehiscence on the plant, 

 as dehiscing fruits they give up the greater part of it to the 

 air, only retaining what is common to both dead and living 

 organised vegetable substances, the water of hygroscopicity. 

 All dehiscing capsules, whether they originally possessed in 

 the full-grown, unopened condition on the plant as much 

 as 94 or 95 per cent, of water, as in Scilla and Momordica^ or 

 as little as 62 or 66 per cent., as in Ravenala and Mahogany, 

 should be classed with dry fruits when they present themselves 

 in the act of freeing their seeds on the plant. It is very 

 questionable whether the expression " dry fruit " has any 

 significance except for the herbarium. Consistently applied, 

 it has no biological value, since the living connection with 

 the parent plant has been severed. 



Let us take the dry, dehiscing fruits of Canna^ Iris, and 

 Datura, which, as we observe them on the plant, certainly 

 deserve that appellation, though they have lost their vitality. 

 When full-grown on the parent and ready to dehisce, they 

 contain (excluding the seeds) from 80 to 90 per cent, of 

 water ; and their soft seeds, as shown by actual experiment 

 on those of Iris Pseudacorus, are able to proceed at once with 

 germination without the interruption of a rest-period. Such 

 are the fruits with which the student of the living plant is 

 chiefly concerned. The dry, dehiscing capsule belongs only 

 to his herbarium. So it is with legumes, as will subsequently 

 be shown, and so it is with the shrivelling berry. All that 

 is purposive ends when a fruit has passed its prime. The 

 fruit dies, let it be a capsule, a legume, or a berry ; and 

 the mode of liberation of its seeds depends on structural 

 characters that were developed when it was a part of a 

 living plant, and could have had no possible concern with 

 the escape of the seeds from a dead fruit. All appear- 

 ances of adaptation to seed-dispersal in fruit-dehiscence are 

 delusive and based on a one-sided view of the subject. 

 We observe all those cases where Nature seems to give 

 her aid and ignore the multitude of others that she seems 



