24 BULLETIN OF THE NATURAL HISTORY SOCIETY. 



VII. utilization of the Poioer of Gravitation. 



As already pointed out this force working in a vertical 

 instead of a lateral direction is of little use in dissemina- 

 tion. It causes seeds to roll down slopes, and undoubtedly 

 aids in the scattering of heavy nuts, which have their 

 outer walls so built that they are elastic, and, falling with 

 force they may strike stones or roots or lower branches 

 and bounce away considerable distances, and this may 

 be helped by wind, water currents, etc. 



III. Some Special Adaptations Connected with the 

 Locomotive Parts. 



In addition to the adaptations to locomotion proper, 

 there are various arrangements connected with the 

 locomotive parts which we cannot here more than 

 mention. Such are the power of planting themselves by 

 utilization of the movements of hygroscopic tissues which 

 bore them into the ground as in Erodiiun and Stipo. 

 jnnnata. In other cases the fruit stalk turns from the 

 light and places the seeds in clefts of rocks on which the 

 plant grows as in Linaria Cymbalaria of Europe. Some 

 plants place their seeds in protective positions while they 

 are ripening, as manj^ water plants which draw them by 

 spirally shortened stems under water. Some seeds have 

 modes of protection against germinating in the fruit, 

 others special arrangements for rapidly absorbing water 

 and perhaps even fastening themselves to the ground. 

 Some fruits open only in favorable weather, others, as in 

 cones of certain pines, appear to open only when scorched 

 by fire, and there are many other arrangements which 

 space does not allow us to mention. 



