XIV 



CONTENTS 



2.62. Mobility .... 

 263. Organs for dissemination 



Contrivances for dissemination 



Position of disseminules 



Seed production . 



Agents of migration . 



264, 

 265, 

 266. 

 267, 



268. The direction of migration 

 Ecesis 



269. Concept 



270. Germination of the seed 



271. Adjustment to the habitat 

 *^rrierss 



272. Concept 



273. Physical barriers 



274. Biological barriers 



275. Influence of barriers . 

 Endemism 



2^6. Concept . . 



277. Causes 



278. Signiticance 

 Polyphylesis and Polygenesis 



279. Concept 



280. Proofs of polygenesis 



281. Origin by polyphylesis 

 Kinds of Invasion 



282. Continuous and intermittent invasion 



283. Complete and partial invasion 



284. Permanent and temporary invasion 

 Manner of Invasion 



285. Entrance into the habitat 



286. Influence of levels 

 Investigation of Invasion 



287 



Succession 



288. Concept 



289. Kinds of succession . . . 

 Primary Successions 



290 



291. Succession through elevation 



292. Succession through volcanic action 



293. Weathering .... 



