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WRIGHT : FOLIAR PERIODICITY 
3. —Glimate in Ceylon and Java 
4. —The Leafless Phase in the Tropics. 
General characteristics. 
Variation in different climates. 
Parts of Ceylon. 
Ceylon and Java ; Peradeniya, Buiten- 
zorg, and East Java. 
Ceylon and Ursprung’s species. 
Variation in the same climate. 
Variation in successive years. 
5. —Transpiration in Ceylon. 
General. 
Periodicity and transpiration. 
6. —The relative importance of the physical factors: 
temperature, rainfall, humidity, and light. 
7. —External and Internal Factors. 
8. —Advantages of Periodical Phenomena. 
9. —Relation of Foliar, Floral, and Fruit Periodi¬ 
cities. 
10. —Foliar Periodicity of Fossil Plants. 
11. —Foliar Periodicity of Endemic Species. 
12. —Foliar Periodicity of Indigenous Species. 
13. —Ceylon Indigenous Species in India. 
Sachs in his “ Lectures on the Physiology of Plants,” in 
1887, stated that, from a study of plants in European 
climates, one is led to infer that foliar periodicity depends 
upon the alternation of seasons and therefore chiefly 
upon temperature and moisture, and, without wishing to 
deny the co-operation of these factors, he suggested that 
periodicity may depend chiefly upon changes which take 
place in the plant, independently of external influences or 
only indirectly affected by them. Haberlandt in his book 
“ Botanische Tropenenreise ” in 1893 draws attention to the 
fact that botanists are inclined, from their knowledge of 
European floras, to connect the periodicity of leaf-fail and 
